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34 results on '"Bonfils, X."'

1. Bright Opportunities for Atmospheric Characterization of Small Planets: Masses and Radii of K2-3 b, c, and d and GJ3470 b from Radial Velocity Measurements and Spitzer Transits

Author

Kosiarek, Molly R, Crossfield, Ian JM, Hardegree-Ullman, Kevin K, Livingston, John H, Benneke, Björn, Henry, Gregory W, Howard, Ward S, Berardo, David, Blunt, Sarah, Fulton, Benjamin J, Hirsch, Lea A, Howard, Andrew W, Isaacson, Howard, Petigura, Erik A, Sinukoff, Evan, Weiss, Lauren, Bonfils, X, Dressing, Courtney D, Knutson, Heather A, Schlieder, Joshua E, Werner, Michael, Gorjian, Varoujan, Krick, Jessica, Morales, Farisa Y, Astudillo-Defru, Nicola, Almenara, J-M, Delfosse, X, Forveille, T, Lovis, C, Mayor, M, Murgas, F, Pepe, F, Santos, NC, Udry, S, Corbett, HT, Fors, Octavi, Law, Nicholas M, Ratzloff, Jeffrey K, and del Ser, Daniel

Subjects
planets and satellites: composition, techniques: photometric, techniques: radial velocities, astro-ph.EP, Astronomical and Space Sciences, Astronomy & Astrophysics
Abstract

We report improved masses, radii, and densities for four planets in two bright M-dwarf systems, K2-3 and GJ3470, derived from a combination of new radial velocity and transit observations. Supplementing K2 photometry with follow-up Spitzer transit observations refined the transit ephemerides of K2-3 b, c, and d by over a factor of 10. We analyze ground-based photometry from the Evryscope and Fairborn Observatory to determine the characteristic stellar activity timescales for our Gaussian Process fit, including the stellar rotation period and activity region decay timescale. The stellar rotation signals for both stars are evident in the radial velocity data and is included in our fit using a Gaussian process trained on the photometry. We find the masses of K2-3 b, K2-3 c, and GJ3470 b to be 6.48, 2.14, and 12.58 M ⊕, respectively. K2-3 d was not significantly detected and has a 3σ upper limit of 2.80 M ⊕ . These two systems are training cases for future TESS systems; due to the low planet densities (ρ < 3.7 g cm -3 ) and bright host stars (K < 9 mag), they are among the best candidates for transmission spectroscopy in order to characterize the atmospheric compositions of small planets.

Published
2019

2. TOI-3568 b: A super-Neptune in the sub-Jovian desert.

Author

Martioli, E., Petrucci, R. P., Jofré, E., Hébrard, G., Ghezzi, L., Gómez Maqueo Chew, Y., Díaz, R. F., Perottoni, H. D., Garcia, L. H., Rapetti, D., Lecavelier des Etangs, A., de Almeida, L., Arnold, L., Artigau, É., Basant, R., Bean, J. L., Bieryla, A., Boisse, I., Bonfils, X., and Brady, M.

Subjects
PLANETARY systems, PLANETARY mass, HOT Jupiters, GAS giants, PLANETARY orbits, ASTRONOMICAL photometry
Abstract

The sub-Jovian desert is a region in the mass-period and radius-period parameter space that typically encompasses short-period ranges between super-Earths and hot Jupiters, and exhibits an intrinsic dearth of planets. This scarcity is likely shaped by photoevaporation caused by the stellar irradiation received by giant planets that have migrated inward. We report the detection and characterization of TOI-3568 b, a transiting super-Neptune with a mass of 26.4 ± 1.0 M⊕, a radius of 5.30 ± 0.27 R⊕, a bulk density of 0.98 ± 0.15 g cm−3, and an orbital period of 4.417965 (5) d situated in the vicinity of the sub-Jovian desert. This planet orbiting a K dwarf star with solar metallicity was identified photometrically by the Transiting Exoplanet Survey Satellite (TESS). It was characterized as a planet by our high-precision radial-velocity (RV) monitoring program using MAROON-X at Gemini North, supplemented with additional observations from the SPICE large program with SPIRou at CFHT. We performed a Bayesian MCMC joint analysis of the TESS and ground-based photometry, and MAROON-X and SPIRou RVs, to measure the orbit, radius, and mass of the planet, as well as a detailed analysis of the high-resolution flux and polarimetric spectra to determine the physical parameters and elemental abundances of the host star. Our results reveal TOI-3568 b to be a hot super-Neptune rich in hydrogen and helium, with a core of heavier elements of between 10 and 25 M⊕ in mass. We analyzed the photoevaporation status of TOI-3568 b and find that it experiences one of the highest extreme-ultraviolet (EUV) luminosities among planets with a mass of Mp < 2 MNep, yet it has an evaporation lifetime exceeding 5 Gyr. Positioned in the transition between two significant populations of exoplanets on the mass-period and energy diagrams, this planet presents an opportunity to test theories concerning the origin of the sub-Jovian desert. [ABSTRACT FROM AUTHOR]

Published
2024
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3. A global analysis of Spitzer and new HARPS data confirms the loneliness and metal-richness of GJ 436 b⋆⋆⋆

Author

Lanotte, AA, Gillon, M, Demory, B-O, Fortney, JJ, Astudillo, N, Bonfils, X, Magain, P, Delfosse, X, Forveille, T, Lovis, C, Mayor, M, Neves, V, Pepe, F, Queloz, D, Santos, N, and Udry, S

Subjects
techniques: photometric, techniques: radial velocities, planetary systems, infrared: general, stars: individual: GJ436, astro-ph.EP, Astronomical and Space Sciences, Astronomy & Astrophysics
Abstract

Context. GJ 436b is one of the few transiting warm Neptunes for which a detailed characterisation of the atmosphere is possible, whereas its non-negligible orbital eccentricity calls for further investigation. Independent analyses of several individual datasets obtained with Spitzer have led to contradicting results attributed to the different techniques used to treat the instrumental effects.

Published
2014

4. TOI-663: A newly discovered multi-planet system with three transiting mini-Neptunes orbiting an early M star.

Author

Cointepas, M., Bouchy, F., Almenara, J. M., Bonfils, X., Astudillo-Defru, N., Knierim, H., Stalport, M., Mignon, L., Grieves, N., Bean, J., Brady, M., Burt, J., Canto Martins, B. L., Collins, K. A., Collins, K. I., Delfosse, X., de Medeiros, J. R., Demory, B.-O., Dorn, C., and Forveille, T.

Subjects
ORBITS (Astronomy), STELLAR orbits, GAUSSIAN processes, PLANETS, INTEGRATED software, EXTRASOLAR planets
Abstract

We present the detection of three exoplanets orbiting the early M dwarf TOI-663 (TIC 54962195; V = 13.7 mag, J = 10.4 mag, R★ = 0.512 ± 0.015 R⊙, M★ = 0.514 ± 0.012 M⊙, d = 64 pc). TOI-663 b, c, and d, with respective radii of 2.27 ± 0.10 R⊕, 2.26 ± 0.10 R⊕, and 1.92 ± 0.13 R⊕ and masses of 4.45 ± 0.65 M⊕, 3.65 ± 0.97 M⊕, and <5.2 M⊕ at 99%, are located just above the radius valley that separates rocky and volatile-rich exoplanets. The planet candidates are identified in two TESS sectors and are validated with ground-based photometric follow-up, precise radial-velocity measurements, and high-resolution imaging. We used the software package juliet to jointly model the photometric and radial-velocity datasets, with Gaussian processes applied to correct for systematics. The three planets discovered in the TOI-663 system are low-mass mini-Neptunes with radii significantly larger than those of rocky analogs, implying that volatiles, such as water, must predominate. In addition to this internal structure analysis, we also performed a dynamical analysis that confirmed the stability of the system. The three exoplanets in the TOI-663 system, similarly to other sub-Neptunes orbiting M dwarfs, have been found to have lower densities than planets of similar sizes orbiting stars of different spectral types. [ABSTRACT FROM AUTHOR]

Published
2024
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5. Connecting photometric and spectroscopic granulation signals with CHEOPS and ESPRESSO

Author

Sulis, S., Lendl, M., Cegla, H. M., Rodriguez Diaz, L. F., Bigot, L., Van Grootel, V., Bekkelien, A., Collier Cameron, A., Maxted, P. F. L., Simon, A. E., Lovis, C., Scandariato, G., Bruno, G., Nardiello, D., Bonfanti, A., Fridlund, M., Persson, C. M., Salmon, S., Sousa, S. G., Wilson, T. G., Krenn, A., Hoyer, S., Santerne, A., Ehrenreich, D., Alibert, Y., Alonso, R., Anglada Escudé, G., Bàrczy, T., Barrado y Navascués, D., Barros, S. C. C., Baumjohann, W., Beck, M., Beck, T., Benz, W., Billot, N., Bonfils, X., Borsato, L., Brandeker, A., Broeg, C., Cabrera, J., Charnoz, S., Corral Van Damme, C., Csizmadia, Sz., Davies, M. B., Deleuil, M., Deline, A., Delrez, L., Demangeon, O. D. S., Demory, B. -O., Erikson, A., Fortier, A., Fossati, L., Gandolfi, D., Gillon, M., Güdel, M., Heng, K., Isaak, K. G., Kiss, L. L., Laskar, J., Lecavelier des Etangs, A., Magrin, D., Munari, M., Nascimbeni, V., Olofsson, G., Ottensamer, R., Pagano, I., Palle, E., Peter, G., Piotto, G., Pollacco, D., Queloz, D., Ragazzoni, R., Rando, N., Rauer, H., Ribas, I., Rieder, M., Santos, N. C., Segransan, D., Smith, A. M. S., Steinberger, M., Steller, M., Szabó, Gy. M., Thomas, N., Udry, S., Walton, N. A., Wolter, D., Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France, Institut de Physique du Globe de Paris (IPGP (UMR_7154)), Institut national des sciences de l'Univers (INSU - CNRS)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut d'Astrophysique de Paris (IAP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Science & Technology Facilities Council, University of St Andrews. School of Physics and Astronomy, University of St Andrews. St Andrews Centre for Exoplanet Science, University of St Andrews. School of Economics and Finance, and University of St Andrews. University of St Andrews

Subjects
radial velocities and photometric [Techniques], FOS: Physical sciences, Sun: granulation, techniques: photometric, stars: atmospheres, techniques: radial velocities, QB Astronomy, atmospheres [Stars], data analysis [Methods], QC, Solar and Stellar Astrophysics (astro-ph.SR), QB, MCC, Earth and Planetary Astrophysics (astro-ph.EP), radial velocities [Techniques], photometric [Techniques], 500 Naturwissenschaften und Mathematik::520 Astronomie::520 Astronomie und zugeordnete Wissenschaften, DAS, Astronomy and Astrophysics, methods: data analysis, QC Physics, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, [SDU]Sciences of the Universe [physics], granulation [Sun], Astrophysics - Earth and Planetary Astrophysics
Abstract

Context. Stellar granulation generates fluctuations in photometric and spectroscopic data whose properties depend on the stellar type, composition, and evolutionary state. Characterizing granulation is key for understanding stellar atmospheres and detecting planets. Aims. We aim to detect the signatures of stellar granulation, link spectroscopic and photometric signatures of convection for mainsequence stars, and test predictions from 3D hydrodynamic models. Methods. For the first time, we observed two bright stars (Teff = 5833 and 6205 K) with high-precision observations taken simultaneously with CHEOPS and ESPRESSO. We analyzed the properties of the stellar granulation signal in each individual dataset. We compared them to Kepler observations and 3D hydrodynamic models. While isolating the granulation-induced changes by attenuating and filtering the p-mode oscillation signals, we studied the relationship between photometric and spectroscopic observables. Results. The signature of stellar granulation is detected and precisely characterized for the hotter F star in the CHEOPS and ESPRESSO observations. For the cooler G star, we obtain a clear detection in the CHEOPS dataset only. The TESS observations are blind to this stellar signal. Based on CHEOPS observations, we show that the inferred properties of stellar granulation are in agreement with both Kepler observations and hydrodynamic models. Comparing their periodograms, we observe a strong link between spectroscopic and photometric observables. Correlations of this stellar signal in the time domain (flux versus radial velocities, RV) and with specific spectroscopic observables (shape of the cross-correlation functions) are however difficult to isolate due to S/N dependent variations. Conclusions. In the context of the upcoming PLATO mission and the extreme precision RV surveys, a thorough understanding of the properties of the stellar granulation signal is needed. The CHEOPS and ESPRESSO observations pave the way for detailed analyses of this stellar process., Astronomy & Astrophysics, 670, ISSN:0004-6361, ISSN:1432-0746

Published
2023
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6. Investigating the architecture and internal structure of the TOI-561 system planets with CHEOPS, HARPS-N and TESS

Author

Lacedelli, G, Wilson, T G, Malavolta, L, Hooton, M. J., Collier Cameron, A, Alibert, Y., Mortier, A, Bonfanti, A, Haywood, R D, Hoyer, S, Piotto, G, Bekkelien, A, Vanderburg, A M, Benz, W., Dumusque, X, Deline, A, L��pez-Morales, M, Borsato, L, Rice, K, Fossati, L, Latham, D W, Brandeker, A, Poretti, E, Sousa, S G, Sozzetti, A, Salmon, S, Burke, C J, Van Grootel, V, Fausnaugh, M M, Adibekyan, V, Huang, C X, Osborn, H. P., Mustill, A J, Pall��, E, Bourrier, V, Nascimbeni, V, Alonso, R, Anglada, G, B��rczy, T, Barrado y Navascues, D, Barros, S C C, Baumjohann, W, Beck, M, Beck, T., Billot, N, Bonfils, X, Broeg, C., Buchhave, L A, Cabrera, J, Charnoz, S, Cosentino, R, Csizmadia, Sz, Davies, M B, Deleuil, M, Delrez, L, Demangeon, O, Demory, B.-O., Ehrenreich, D, Erikson, A, Esparza-Borges, E, Flor��n, H G, Fortier, A., Fridlund, M, Futyan, D, Gandolfi, D, Ghedina, A, Gillon, M, G��del, M, Guterman, P, Harutyunyan, A, Heng, K., Isaak, K G, Jenkins, J M, Kiss, L, Laskar, J, Lecavelier des Etangs, A, Lendl, M, Lovis, C, Magrin, D, Marafatto, L, Martinez Fiorenzano, A F, Maxted, P F L, Mayor, M, Micela, G, Molinari, E, Murgas, F, Narita, N, Olofsson, G, Ottensamer, R, Pagano, I, Pasetti, A, Pedani, M, Pepe, F A, Peter, G, Phillips, D F, Pollacco, D, Queloz, D, Ragazzoni, R, Rando, N, Ratti, F, Rauer, H, Ribas, I, Santos, N C, Sasselov, D, Scandariato, G, Seager, S, S��gransan, D, Serrano, L M, Simon, A E, Smith, A M S, Steinberger, M, Steller, M, Szab��, Gy, Thomas, N., Twicken, J D, Udry, S, Walton, N, Winn, J N, National Science Foundation (US), National Aeronautics and Space Administration (US), European Space Agency, European Research Council, European Commission, Agencia Estatal de Investigación (España), Ministerio de Ciencia, Innovación y Universidades (España), Ministerio de Economía y Competitividad (España), Generalitat de Catalunya, Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France, Institut de Physique du Globe de Paris (IPGP (UMR_7154)), Institut national des sciences de l'Univers (INSU - CNRS)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut d'Astrophysique de Paris (IAP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Science & Technology Facilities Council, University of St Andrews. School of Physics and Astronomy, and University of St Andrews. St Andrews Centre for Exoplanet Science

Subjects
stars, stars: individual: TOI-561 (TIC 377064495, individual: TOI-561 (TIC 377064495 [Stars], fundamental parameters [Planets and satellites], TOI-561 TIC 377064495, Planets and satellites: interiors, stars: individual: TOI-561 (TIC 377064495. Gaia EDR3 3850421005290172416), FOS: Physical sciences, techniques radial velocities, QB460, QB Astronomy, Gaia EDR3 3850421005290172416), individual, QA, QB600, QC, Gaia EDR3 3850421005290172416, QB, Earth and Planetary Astrophysics (astro-ph.EP), radial velocities [Techniques], [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 520 Astronomy, planets and satellites interiors, photometric [Techniques], Astronomy and Astrophysics, DAS, 620 Engineering, interiors [Planets and satellites], Planets and satellites: fundamental parameters, techniques photometric, QC Physics, Space and Planetary Science, [SDU]Sciences of the Universe [physics], planets and satellites fundamental parameters, MCP, Techniques: radial velocities, astro-ph.EP, Techniques: photometric, Astrophysics - Earth and Planetary Astrophysics
Abstract

G. Lacedelli et al., We present a precise characterization of the TOI-561 planetary system obtained by combining previously published data with TESS and CHEOPS photometry, and a new set of 62 HARPS-N radial velocities (RVs). Our joint analysis confirms the presence of four transiting planets, namely TOI-561 b (P = 0.45 d, R = 1.42 R⊕, M = 2.0 M⊕), c (P = 10.78 d, R = 2.91 R⊕, M = 5.4 M⊕), d (P = 25.7 d, R = 2.82 R⊕, M = 13.2 M⊕), and e (P = 77 d, R = 2.55 R⊕, M = 12.6 R⊕). Moreover, we identify an additional, long-period signal (>450 d) in the RVs, which could be due to either an external planetary companion or to stellar magnetic activity. The precise masses and radii obtained for the four planets allowed us to conduct interior structure and atmospheric escape modelling. TOI-561 b is confirmed to be the lowest density (ρb = 3.8 ± 0.5 g cm−3) ultra-short period (USP) planet known to date, and the low metallicity of the host star makes it consistent with the general bulk density-stellar metallicity trend. According to our interior structure modelling, planet b has basically no gas envelope, and it could host a certain amount of water. In contrast, TOI-561 c, d, and e likely retained an H/He envelope, in addition to a possibly large water layer. The inferred planetary compositions suggest different atmospheric evolutionary paths, with planets b and c having experienced significant gas loss, and planets d and e showing an atmospheric content consistent with the original one. The uniqueness of the USP planet, the presence of the long-period planet TOI-561 e, and the complex architecture make this system an appealing target for follow-up studies., CHEOPS is an ESA mission in partnership with Switzerland with important contributions to the payload and the ground segment from Austria, Belgium, France, Germany, Hungary, Italy, Portugal, Spain, Sweden, and the United Kingdom. The CHEOPS Consortium gratefully acknowledge the support received by all the agencies, offices, universities, and industries involved. Their flexibility and willingness to explore new approaches were essential to the success of the mission. This work is based on observations made with the Italian Telescopio Nazionale Galileo (TNG) operated on the island of La Palma by the Fundación Galileo Galilei of the INAF at the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias (GTO program, and A40TAC_23 program from INAF-TAC). The HARPS-N project was funded by the Prodex Program of the Swiss Space Office (SSO), the Harvard University Origin of Life Initiative (HUOLI), the Scottish Universities Physics Alliance (SUPA), the University of Geneva, the Smithsonian Astrophysical Observatory (SAO), and the Italian National Astrophysical Institute (INAF), University of St. Andrews, Queen’s University Belfast and University of Edinburgh. This paper includes data collected by the TESS mission, which are publicly available from the Mikulski Archive for Space Telescopes (MAST). Funding for the TESS mission is provided by the NASA Explorer Program. Resources supporting this work were provided by the NASA High-End Computing (HEC) Program through the NASA Advanced Supercomputing (NAS) Division at Ames Research Center for the production of the SPOC data products. This research has made use of the NASA Exoplanet Archive, which is operated by the California Institute of Technology, under contract with the National Aeronautics and Space Administration under the Exoplanet Exploration Program. This research has made use of data obtained from the portal http://www.exoplanet.eu/ of The Extrasolar Planets Encyclopaedia. This work has made use of data from the European Space Agency (ESA) mission Gaia (https://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC, https://www.cosmos.esa.int/web/gaia/dpac/consortium). Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. This publication makes use of data products from the Two Micron All Sky Survey, which is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center/California Institute of Technology, funded by the National Aeronautics and Space Administration and the National Science Foundation. GL acknowledges support by CARIPARO Foundation, according to the agreement CARIPARO-Università degli Studi di Padova (Pratica n. 2018/0098). TW and ACC acknowledge support from STFC consolidated grant numbers ST/R000824/1 and ST/V000861/1, and UKSA grant number ST/R003203/1. YA, MJH, B-OD, and ML acknowledge the support of the Swiss National Fundation under grant numbers 200020_172746, PP00P2-190080, and PCEFP2_194576. SH gratefully acknowledges CNES funding through the grant number 837319. GPi, VNa, GSs, IPa, LBo, and RRa acknowledge the funding support from Italian Space Agency (ASI) regulated by ‘Accordo ASI-INAF n. 2013-016-R.0 del 9 luglio 2013 e integrazione del 9 luglio 2015 CHEOPS Fasi A/B/C’. ADe acknowledges support from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (project FOUR ACES, grant agreement No. 724427), and from the National Centre for Competence in Research ‘PlanetS’ supported by the Swiss National Science Foundation (SNSF). KR is grateful for support from the UK STFC via grant number ST/V000594/1. This work has been supported by the National Aeronautics and Space Administration under grant number NNX17AB59G, issued through the Exoplanets Research Program. S.S. has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement no. 833925, project STAREX). MG is an F.R.S.-FNRS Senior Research Associate. VVG is an F.R.S-FNRS Research Associate. LD is an F.R.S.-FNRS Postdoctoral Researcher. This work has been carried out within the framework of the NCCR PlanetS supported by the Swiss National Science Foundation. AMu and MF acknowledge support from the Swedish National Space Agency (career grant numbers 120/19C, DNR 65/19, 174/18). ABr was supported by the SNSA. We acknowledge support from the Spanish Ministry of Science and Innovation and the European Regional Development Fund through grant numbers ESP2016-80435-C2-1-R, ESP2016-80435-C2-2-R, PGC2018-098153-B-C33, PGC2018-098153-B-C31, ESP2017-87676-C5-1-R,MDM-2017-0737 Unidad de Excelencia Maria de Maeztu-Centro de Astrobiología (INTA-CSIC), as well as the support of the Generalitat de Catalunya/CERCA programme. The MOC activities have been supported by the ESA contract no. 4000124370. SGS, SCCB, and VA acknowledge support from FCT through FCT contract nr. CEECIND/00826/2018, POPH/FSE (EC), nr. IF/01312/2014/CP1215/CT0004, and IF/00650/2015/CP1273/CT0001, respectively. ODSD is supported in the form of work contract (DL 57/2016/CP1364/CT0004) funded by national funds through FCT. XB, SC, DG, MF, and JL acknowledge their role as ESA-appointed CHEOPS science team members. The Belgian participation to CHEOPS has been supported by the Belgian Federal Science Policy Office (BELSPO) in the framework of the PRODEX Program, and by the University of Liège through an ARC grant for Concerted Research Actions financed by the Wallonia-Brussels Federation. This work was supported by FCT – Fundação para a Ciência e a Tecnologia through national funds and by FEDER through COMPETE2020 – Programa Operacional Competitividade e Internacionalizacão by these grants UID/FIS/04434/2019, UIDB/04434/2020, UIDP/04434/2020, PTDC/FIS-AST/32113/2017 & POCI-01-0145-FEDER-032113,PTDC/FIS-AST/28953/2017 & POCI-01-0145-FEDER-028953,PTDC/FIS-AST/28987/2017 & POCI-01-0145-FEDER-028987. This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (project FOUR ACES, grant agreement no. 724427). DG and LMS gratefully acknowledge financial support from the CRT foundation under grant number 2018.2323 ‘Gaseousor rocky? Unveiling the nature of small worlds’. KGI is the ESA CHEOPS Project Scientist and is responsible for the ESA CHEOPS Guest Observers Programme. She does not participate in, or contribute to, the definition of the Guaranteed Time Programme of the CHEOPS mission through which observations described in this paper have been taken, nor to any aspect of target selection for the programme. This work was granted access to the HPC resources of MesoPSL financed by the Region Ile de France and the project Equip@Meso (reference ANR-10-EQPX-29-01) of the programme Investissements d’Avenir supervised by the Agence Nationale pour la Recherche. PM acknowledges support from STFC research grant number ST/M001040/1. This work was also partially supported by a grant from the Simons Foundation (PI: Queloz, grant number 327127). GyMSz acknowledges the support of the Hungarian National Research, Development and Innovation Office (NKFIH) grant K-125015, a PRODEX Institute Agreement between the ELTE Eötvös Loránd University and the European Space Agency (ESA-D/SCI-LE-2021-0025), the Lendület LP2018-7/2021 grant of the Hungarian Academy of Science and the support of the city of Szombathely. This work is partly supported by JSPS KAKENHI grant number JP18H05439, JST CREST grant number JPMJCR1761, the Astrobiology Center of National Institutes of Natural Sciences (NINS) (grant number AB031010). EE-B acknowledges financial support from the European Union and the State Agency of Investigation of the Spanish Ministry of Science and Innovation (MICINN) under the grant number PRE2020-093107 of the Pre-Doc Program for the Training of Doctors (FPI-SO) through FSE funds.

Published
2022
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7. A CHEOPS-enhanced view of the HD 3167 system

Author

Bourrier, V., Deline, A., Krenn, A., Egger, J. A., Petit, A. C., Malavolta, L., Cretignier, M., Billot, N., Broeg, C., Florén, H.-G., Queloz, D., Alibert, Y., Bonfanti, A., Bonomo, A. S., Delisle, J.-B., Demangeon, O. D. S., Demory, B.-O., Dumusque, X., Ehrenreich, D., Haywood, R. D., Howell, S. B., Lendl, M., Mortier, A., Nigro, G., Salmon, S., Sousa, S. G., Wilson, T. G., Adibekyan, V., Alonso, R., Anglada, G., Bárczy, T., Barrado y Navascues, D., Barros, S. C. C., Baumjohann, W., Beck, M., Benz, W., Biondi, F., Bonfils, X., Brandeker, A., Cabrera, J., Charnoz, S., Csizmadia, Sz., Collier Cameron, A., Damasso, M., Davies, M. B., Deleuil, M., Delrez, L., Di Fabrizio, L., Erikson, A., Fortier, A., Fossati, L., Fridlund, M., Gandolfi, D., Gillon, M., Güdel, M., Heng, K., Hoyer, S., Isaak, K. G., Kiss, L. L., Laskar, J., Lecavelier des Etangs, A., Lorenzi, V., Lovis, C., Magrin, D., Massa, A., Maxted, P. F. L., Nascimbeni, V., Olofsson, G., Ottensamer, R., Pagano, I., Pallé, E., Peter, G., Piotto, G., Pollacco, D., Ragazzoni, R., Rando, N., Rauer, H., Ribas, I., Santos, N. C., Scandariato, G., Ségransan, D., Simon, A., Smith, A. M. S., Steller, M., Szabó, Gy. M., Thomas, N., Udry, S., Van Grootel, V., Verrecchia, F., Walton, N., Beck, T., Buder, M., Ratti, F., Ulmer, B., Viotto, V., Observatoire Astronomique de l'Université de Genève (ObsGE), Université de Genève = University of Geneva (UNIGE), Austrian Academy of Sciences (OeAW), University of Bern, University of Copenhagen = Københavns Universitet (UCPH), INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), AlbaNova University Center, Stockholm University, Departement Physik [ETH Zürich] (D-PHYS), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Cavendish Laboratory, University of Cambridge [UK] (CAM), INAF - Osservatorio Astrofisico di Torino (OATo), Instituto de Astrofísica e Ciências do Espaço (IASTRO), Center for Space and Habitability (CSH), University of Exeter, NASA Ames Research Center (ARC), Università degli Studi di Padova = University of Padua (Unipd), University of St Andrews [Scotland], Faculdade de Ciências [Lisboa], Universidade de Lisboa = University of Lisbon (ULISBOA), Instituto de Astrofisica de Canarias (IAC), Universidad de La Laguna [Tenerife - SP] (ULL), Institut de Ciencies de l'Espai [Barcelona] (ICE-CSIC), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Institut d'Estudis Espacials de Catalunya (IEEC-CSIC), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Faculdade de Ciências da Universidade do Porto (FCUP), Universidade do Porto = University of Porto, Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France, German Aerospace Center (DLR), Institut de Physique du Globe de Paris (IPGP (UMR_7154)), Institut national des sciences de l'Univers (INSU - CNRS)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Lund University [Lund], Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Université de Liège, Fundación Galileo Galilei - INAF, Leiden Observatory [Leiden], Universiteit Leiden, Università degli studi di Torino = University of Turin (UNITO), University of Vienna [Vienna], European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut d'Astrophysique de Paris (IAP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Keele University [Keele], INAF - Osservatorio Astrofisico di Catania (OACT), University of Warwick [Coventry], ESA - ESTEC (Netherlands), Gothard Astrophysical Observatory, Space Sciences, Technologies and Astrophysics Research Institute (STAR), INAF - Osservatorio Astronomico di Roma (OAR), Swiss National Science Foundation, European Research Council, European Commission, European Space Agency, Ministerio de Economía y Competitividad (España), Fundação para a Ciência e a Tecnologia (Portugal), Agencia Estatal de Investigación (España), Ministerio de Ciencia, Innovación y Universidades (España), Generalitat de Catalunya, Science & Technology Facilities Council, University of St Andrews. School of Physics and Astronomy, and University of St Andrews. St Andrews Centre for Exoplanet Science

Subjects
Planet-star interactions, planets and satellites: physical evolution, planets and satellites: dynamical evolution and stability, 530 Physics, FOS: Physical sciences, individual: HD 3167 [Planets and satellites], techniques: photometric, techniques: radial velocities, planet-star interactions, QB Astronomy, planets and satellites: individual: HD 3167, Solar and Stellar Astrophysics (astro-ph.SR), physical evolution [Planets and satellites], QB, Earth and Planetary Astrophysics (astro-ph.EP), MCC, radial velocities [Techniques], 520 Astronomy, photometric [Techniques], 500 Naturwissenschaften und Mathematik::520 Astronomie::520 Astronomie und zugeordnete Wissenschaften, Astronomy and Astrophysics, 3rd-DAS, 500 Science, 620 Engineering, dynamical evolution and stability [Planets and satellites], Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Astrophysics - Earth and Planetary Astrophysics
Abstract

CHEOPS Consortium: V. Bourrier et al., Much remains to be understood about the nature of exoplanets smaller than Neptune, most of which have been discovered in compact multi-planet systems. With its inner ultra-short period planet b aligned with the star and two larger outer planets d-c on polar orbits, the multi-planet system HD 3167 features a peculiar architecture and offers the possibility to investigate both dynamical and atmospheric evolution processes. To this purpose we combined multiple datasets of transit photometry and radial velocimetry (RV) to revise the properties of the system and inform models of its planets. This effort was spearheaded by CHEOPS observations of HD 3167b, which appear inconsistent with a purely rocky composition despite its extreme irradiation. Overall the precision on the planetary orbital periods are improved by an order of magnitude, and the uncertainties on the densities of the transiting planets b and c are decreased by a factor of 3. Internal structure and atmospheric simulations draw a contrasting picture between HD 3167d, likely a rocky super-Earth that lost its atmosphere through photo-evaporation, and HD 3167c, a mini-Neptune that kept a substantial primordial gaseous envelope. We detect a fourth, more massive planet on a larger orbit, likely coplanar with HD 3167d-c. Dynamical simulations indeed show that the outer planetary system d-c-e was tilted, as a whole, early in the system history, when HD 3167b was still dominated by the star influence and maintained its aligned orbit. RV data and direct imaging rule out that the companion that could be responsible for the present-day architecture is still bound to the HD 3167 system. Similar global studies of multi-planet systems will tell how many share the peculiar properties of the HD 3167 system, which remains a target of choice for follow-up observations and simulations., This work has been carried out in the frame of the National Centre for Competence in Research PlanetS supported by the Swiss National Science Foundation (SNSF). D. E. acknowledges financial support from the Swiss National Science Foundation for project 200021_200726. This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (project SPICE DUNE, grant agreement No 947634; project FOUR ACES, grant agreement 724427; project SCORE, grant agreement No 851555). CHEOPS is an ESA mission in partnership with Switzerland with important contributions to the payload and the ground segment from Austria, Belgium, France, Germany, Hungary, Italy, Portugal, Spain, Sweden, and the United Kingdom. The CHEOPS Consortium would like to gratefully acknowledge the support received by all the agencies, offices, universities, and industries involved. Their flexibility and willingness to explore new approaches were essential to the success of this mission. A. C. C. acknowledges support from STFC consolidated grant numbers ST/R000824/1 and ST/V000861/1, and UKSA grant number ST/R003203/1. S. G. S. acknowledges support from FCT through FCT contract nr. CEECIND/00826/2018 and POPH/FSE (EC). A. C. C. and T. G. W. acknowledge support from STFC consolidated grant numbers ST/R000824/1 and ST/V000861/1, and UKSA grant number ST/R003203/1. Y. A., M. J. H. and J. A. E. acknowledge the support of the Swiss National Fund under grant 200020_172746. We acknowledge support from the Spanish Ministry of Science and Innovation and the European Regional Development Fund through grants ESP2016-80435-C2-1-R, ESP2016-80435-C2-2-R, PGC2018-098153-B-C33, PGC2018-098153-B-C31, ESP2017-87676-C5-1-R, MDM-2017-0737 Unidad de Excelencia Maria de Maeztu-Centro de Astrobiología (INTA-CSIC), as well as the support of the Generalitat de Catalunya/CERCA programme. The MOC activities have been supported by the ESA contract No. 4000124370. S. C. C. B. acknowledges support from FCT through FCT contracts nr. IF/01312/2014/CP1215/CT0004. X. B., S. C., D. G., M. F. and J. L. acknowledge their role as ESA-appointed CHEOPS science team members. A. Br. was supported by the SNSA. This project was supported by the CNES. The Belgian participation to CHEOPS has been supported by the Belgian Federal Science Policy Office (BELSPO) in the framework of the PRODEX Program, and by the University of Liège through an ARC grant for Concerted Research Actions financed by the Wallonia-Brussels Federation. L. D. is an F. R. S.-FNRS Postdoctoral Researcher. This work was supported by FCT - Fundação para a Ciência e a Tecnologia through national funds and by FEDER through COMPETE2020 - Programa Operacional Competitividade e Internacionalizacão by these grants: UID/FIS/04434/2019, UIDB/04434/2020, UIDP/04434/2020, PTDC/FIS-AST/32113/2017 & POCI-01-0145-FEDER-032113, PTDC/FIS-AST/28953/2017 & POCI-01-0145-FEDER-028953, PTDC/FIS-AST/28987/2017 & POCI-01-0145-FEDER-028987, O. D. S. D. is supported in the form of work contract (DL 57/2016/CP1364/CT0004) funded by national funds through FCT. B. -O. D. acknowledges support from the Swiss National Science Foundation (PP00P2-190080). R. D. H. is funded by the UK Science and Technology Facilities Council (STFC)’s Ernest Rutherford Fellowship (grant number ST/V004735/1). M. F. and C. M. P. gratefully acknowledge the support of the Swedish National Space Agency (DNR 65/19, 174/18). D. G. gratefully acknowledges financial support from the CRT foundation under Grant No. 2018.2323 “Gaseous or rocky? Unveiling the nature of small worlds”. M. G. is an F.R.S.-FNRS Senior Research Associate. S. H. gratefully acknowledges CNES funding through the grant 837319. K. G. I. is the ESA CHEOPS Project Scientist and is responsible for the ESA CHEOPS Guest Observers Programme. She does not participate in, or contribute to, the definition of the Guaranteed Time Programme of the CHEOPS mission through which observations described in this paper have been taken, nor to any aspect of target selection for the programme. This work was granted access to the HPC resources of MesoPSL financed by the Region Île-de-France and the project Equip@Meso (reference ANR-10-EQPX-29-01) of the programme Investissements d’Avenir supervized by the Agence Nationale pour la Recherche. M. L. acknowledges support of the Swiss National Science Foundation under grant number PCEFP2_194576. PM acknowledges support from STFC research grant number ST/M001040/1. GSc, GPi, IPa, LBo, VNa and RRa acknowledge the funding support from Italian Space Agency (ASI) regulated by “Accordo ASI-INAF n. 2013-016-R.0 del 9 luglio 2013 e integrazione del 9 luglio 2015 CHEOPS Fasi A/B/C”. This work was also partially supported by a grant from the Simons Foundation (PI Queloz, grant number 327127). I. R. I. acknowledges support from the Spanish Ministry of Science and Innovation and the European Regional Development Fund through grant PGC2018-098153-B- C33, as well as the support of the Generalitat de Catalunya/CERCA programme. Gy. M. Sz. acknowledges the support of the Hungarian National Research, Development and Innovation Office (NKFIH) grant K-125015, a PRODEX Institute Agreement between the ELTE Eötvös Loránd University and the European Space Agency (ESA-D/SCI-LE-2021-0025), the Lendület LP2018-7/2021 grant of the Hungarian Academy of Science and the support of the city of Szombathely. V.V.G. is an F.R.S-FNRS Research Associate. This work has made use of data from the European Space Agency (ESA) mission Gaia (https://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC, https://www.cosmos.esa.int/web/gaia/dpac/consortium). Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. Some of the observations in the paper made use of the High-Resolution Imaging instrument ‘Alopeke obtained under Gemini LLP Proposal Number: GN/S-2021A-LP-105. ‘Alopeke was funded by the NASA Exoplanet Exploration Program and built at the NASA Ames Research Center by Steve B. Howell, Nic Scott, Elliott P. Horch, and Emmett Quigley. Alopeke was mounted on the Gemini North (and/or South) telescope of the international Gemini Observatory, a program of NSF’s OIR Lab, which is managed by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with the National Science Foundation. on behalf of the Gemini partnership: the National Science Foundation (United States), National Research Council (Canada), Agencia Nacional de Investigación y Desarrollo (Chile), Ministerio de Ciencia, Tecnología e Innovación (Argentina), Ministério da Ciência, Tecnologia, Inovações e Comunicações (Brazil), and Korea Astronomy and Space Science Institute (Republic of Korea).

Published
2022
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8. TOI-1055 b: Neptunian planet characterised with HARPS, TESS, and CHEOPS

Author

Bonfanti, A., Gandolfi, D., Egger, J. A., Fossati, L., Cabrera, J., Krenn, A., Alibert, Y., Benz, W., Billot, N., Florén, H.-G., Lendl, M., Adibekyan, V., Salmon, S., Santos, N. C., Sousa, S. G., Wilson, T. G., Barragán, O., Collier Cameron, A., Delrez, L., Esposito, M., Goffo, E., Osborne, H., Osborn, H. P., Serrano, L. M., Van Eylen, V., Alarcon, J., Alonso, R., Anglada, G., Bárczy, T., Barrado Navascues, D., Barros, S. C. C., Baumjohann, W., Beck, M., Beck, T., Bedell, M., Bonfils, X., Borsato, L., Brandeker, A., Broeg, C., Charnoz, S., Corral Van Damme, C., Csizmadia, Sz., Cubillos, P. E., Davies, M. B., Deleuil, M., Demangeon, O. D. S., Demory, B.-O., Ehrenreich, D., Erikson, A., Fortier, A., Fridlund, M., Gillon, M., Güdel, M., Hoyer, S., Isaak, K. G., Kerschbaum, F., Kiss, L. L., Laskar, J., Lecavelier des Etangs, A., Lorenzo-Oliveira, D., Lovis, C., Magrin, D., Marafatto, L., Maxted, P. F. L., Meléndez, J., Mordasini, C., Nascimbeni, V., Olofsson, G., Ottensamer, R., Pagano, I., Pallé, E., Peter, G., Piazza, D., Piotto, G., Pollacco, D., Queloz, D., Ragazzoni, R., Rando, N., Rauer, H., Ribas, I., Scandariato, G., Ségransan, D., Simon, A. E., Smith, A. M. S., Steller, M., Szabó, Gy. M., Thomas, N., Udry, S., Ulmer, B., Van Grootel, V., Venturini, J., Walton, N. A., Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France, Institut de Physique du Globe de Paris (IPGP (UMR_7154)), Institut national des sciences de l'Univers (INSU - CNRS)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut d'Astrophysique de Paris (IAP), and Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Earth and Planetary Astrophysics (astro-ph.EP), 530 Physics, 520 Astronomy, 500 Naturwissenschaften und Mathematik::520 Astronomie::520 Astronomie und zugeordnete Wissenschaften, FOS: Physical sciences, 610 Medicine & health, Astronomy and Astrophysics, 620 Engineering, techniques: photometric, [SDU]Sciences of the Universe [physics], Space and Planetary Science, techniques: radial velocities, 570 Life sciences, biology, stars: fundamental parameters, planets and satellites: fundamental parameters, Astrophysics - Earth and Planetary Astrophysics
Abstract

TOI-1055 is a Sun-like star known to host a transiting Neptune-sized planet on a 17.5-day orbit (TOI-1055 b). Radial velocity (RV) analyses carried out by two independent groups using nearly the same set of HARPS spectra have provided measurements of planetary masses that differ by $\sim$ 2$\sigma$. Our aim in this work is to solve the inconsistency in the published planetary masses by significantly extending the set of HARPS RV measurements and employing a new analysis tool that is able to account and correct for stellar activity. Our further aim was to improve the precision on measurements of the planetary radius by observing two transits of the planet with the CHEOPS space telescope. We fit a skew normal (SN) function to each cross correlation function extracted from the HARPS spectra to obtain RV measurements and hyperparameters to be used for the detrending. We evaluated the correlation changes of the hyperparameters along the RV time series using the breakpoint technique. We performed a joint photometric and RV analysis using a Markov chain Monte Carlo (MCMC) scheme to simultaneously detrend the light curves and the RV time series. We firmly detected the Keplerian signal of TOI-1055 b, deriving a planetary mass of $M_b=20.4_{-2.5}^{+2.6} M_{\oplus}$ ($\sim$12%). This value is in agreement with one of the two estimates in the literature, but it is significantly more precise. Thanks to the TESS transit light curves combined with exquisite CHEOPS photometry, we also derived a planetary radius of $R_b=3.490_{-0.064}^{+0.070} R_{\oplus}$ ($\sim$1.9%). Our mass and radius measurements imply a mean density of $\rho_b=2.65_{-0.35}^{+0.37}$ g cm$^{-3}$ ($\sim$14%). We further inferred the planetary structure and found that TOI-1055 b is very likely to host a substantial gas envelope with a mass of $0.41^{+0.34}_{-0.20}$ M$_\oplus$ and a thickness of $1.05^{+0.30}_{-0.29}$ R$_\oplus$., Comment: 13 pages, 6 figures, 5 tables. Accepted for publication in A&A

Published
2023
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9. XIII. Two planets around M-dwarfs Gl617A and Gl96

Author

Hobson, M. J., Díaz, R. F., Delfosse, X., Astudillo-Defru, N., Boisse, I., Bouchy, F., Bonfils, X., Forveille, T., Hara, N., Arnold, L., Borgniet, S., Bourrier, V., Brugger, B., Cabrera, N., Courcol, B., Dalal, S., Deleuil, M., Demangeon, O., Dumusque, X., Ehrenreich, D., Hébrard, G., Kiefer, F., Lopez, T., Mignon, L., Montagnier, G., Mousis, O., Moutou, C., Pepe, F., Rey, J., Santerne, A., Santos, N., Stalport, M., Ségransan, D., Udry, S., Wilson, P. A., Institut d'Astrophysique de Paris (IAP), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Observatoire Astronomique de l'Université de Genève (ObsGE), Université de Genève (UNIGE), Laboratoire d'Astrophysique de Marseille (LAM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Centre National de la Recherche Scientifique (CNRS)-Université de Lille-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Institut Pythéas (OSU PYTHEAS), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut de Recherche pour le Développement (IRD), Departamento de Matemática y Fı́sica Aplicadas [Concepcion] (DMFA), Universidad Católica de la Santísima Concepción (UCSC), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Universidad de Concepción - University of Concepcion [Chile], Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Centre National de la Recherche Scientifique (CNRS), Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213) (UTINAM), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud - Paris 11 (UP11), Université de Genève = University of Geneva (UNIGE), Laboratoire de Génie de la Conception (LGeco), Institut National des Sciences Appliquées - Strasbourg (INSA Strasbourg), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA), Centro de Astrofísica da Universidade do Porto (CAUP), Universidade do Porto = University of Porto, University of Warwick [Coventry], Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Universidad de Concepción [Chile], Universidade do Porto [Porto], Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France, Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), and Universidade do Porto

Subjects
[SDU]Sciences of the Universe [physics], stars: late-type, techniques: radial velocities, stars: individual: Gl617A, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], planetary systems, stars: individual: Gl96
Abstract

International audience; Aims. Since 2011, the SOPHIE spectrograph has been used to search for Neptunes and super-Earths in the northern hemisphere. As part of this observational program, 290 radial velocity measurements of the 6.4 V magnitude star HD 158259 were obtained. Additionally, TESS photometric measurements of this target are available. We present an analysis of the SOPHIE data and compare our results with the output of the TESS pipeline.Methods. The radial velocity data, ancillary spectroscopic indices, and ground-based photometric measurements were analyzed with classical and ℓ1 periodograms. The stellar activity was modeled as a correlated Gaussian noise and its impact on the planet detection was measured with a new technique.Results. The SOPHIE data support the detection of five planets, each with m sin i ≈ 6 M⊕, orbiting HD 158259 in 3.4, 5.2, 7.9, 12, and 17.4 days. Though a planetary origin is strongly favored, the 17.4 d signal is classified as a planet candidate due to a slightly lower statistical significance and to its proximity to the expected stellar rotation period. The data also present low frequency variations, most likely originating from a magnetic cycle and instrument systematics. Furthermore, the TESS pipeline reports a significant signal at 2.17 days corresponding to a planet of radius ≈1.2 R⊕. A compatible signal is seen in the radial velocities, which confirms the detection of an additional planet and yields a ≈2 M⊕ mass estimate.Conclusions. We find a system of five planets and a strong candidate near a 3:2 mean motion resonance chain orbiting HD 158259. The planets are found to be outside of the two and three body resonances.

Published
2020
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10. Seven new brown dwarfs and constraints on the brown dwarf desert

Author

Kiefer, F., Hébrard, G., Sahlmann, J., Sousa, S. G., Forveille, T., Santos, N., Mayor, M., Deleuil, M., Wilson, P. A., Dalal, S., Díaz, R. F., Henry, G. W., Hagelberg, J., Hobson, M. J., Demangeon, O., Bourrier, V., Delfosse, X., Arnold, L., Astudillo-Defru, N., Beuzit, J.-L., Boisse, I., Bonfils, X., Borgniet, S., Bouchy, F., Courcol, B., Ehrenreich, D., Hara, N., Lagrange, A.-M., Lovis, C., Montagnier, G., Moutou, C., Pepe, F., Perrier, C., Rey, J., Santerne, A., Ségransan, D., Udry, S., Vidal-Madjar, A., Laboratoire de Génie de la Conception (LGeco), Institut National des Sciences Appliquées - Strasbourg (INSA Strasbourg), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA), Institut d'Astrophysique de Paris (IAP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Centro de Astrofísica da Universidade do Porto (CAUP), Universidade do Porto, Observatoire Astronomique de l'Université de Genève (ObsGE), Université de Genève (UNIGE), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Universidade do Porto = University of Porto, Université de Genève = University of Geneva (UNIGE), Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Universidade de Sao Paulo, Instituto Ocenografico, Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Universidade do Porto [Porto], University of Warwick [Coventry], Center of Excellence in Information Systems, Université Paris-Sud - Paris 11 (UP11), Institut Pythéas (OSU PYTHEAS), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Centre National de la Recherche Scientifique (CNRS), Universidad de Concepción [Chile], Tri ionique par les Systèmes Moléculaires auto-assemblés (LTSM), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Université de Montpellier (UM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Université de Montpellier (UM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), and Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut de Recherche pour le Développement (IRD)

Subjects
[PHYS]Physics [physics], observational -methods, numerical, [SDU]Sciences of the Universe [physics], radial velocities -methods, techniques: radial velocities, brown dwarfs -binaries, methods: observational, spectroscopic -techniques, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], binaries: spectroscopic, methods: numerical, brown dwarfs
Abstract

International audience; Context. Brown dwarfs (BD) are substellar objects intermediate between planets and stars with masses of 13-80 MJ. While isolated BDs are most likely produced by gravitational collapse in molecular clouds down to masses of a few MJ, a non-negligible fraction of low-mass companions might be formed through the planet-formation channel in protoplanetary discs. The upper mass limit of objects formed within discs is still observationally unknown, the main reason being the strong dearth of BD companions at orbital periods shorter than 10 yr, also known as the BD desert. Aims: To address this question, we aim at determining the best statistics of companions within the 10-100 MJ mass regime and located closer than 10 au to the primary star, while minimising observation and selection bias. Methods: We made extensive use of the radial velocity (RV) surveys of northern hemisphere FGK stars within 60 pc of the Sun, performed with the SOPHIE spectrograph at the Observatoire de Haute-Provence. We derived the Keplerian solutions of the RV variations of 54 sources. Public astrometric data of the HIPPARCOS and Gaia missions allowed us to constrain the masses of the companions for most sources. We introduce GASTON, a new method to derive inclination combining RVs and Keplerian and astrometric excess noise from Gaia DR1. Results: We report the discovery of 12 new BD candidates. For five of them, additional astrometric data led to a revision of their mass in the M-dwarf regime. Among the seven remaining objects, four are confirmed BD companions, and three others are likely also in this mass regime. Moreover, we report the detection of 42 M-dwarfs within the range of 90 MJ-0.52 M⊙. The resulting M sin i-P distribution of BD candidates shows a clear drop in the detection rate below 80-day orbital period. Above that limit, the BD desert appears rather wet, with a uniform distribution of the M sin i. We derive a minimum BD-detection frequency around Solar-like stars of 2.0 ± 0.5%. RV data are only available at the CDS and Tables B.1, B.3-B.7 are also available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/631/A125

Published
2019
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11. Characterization of the L 98-59 multi-planetary system with HARPS

Author

Cloutier, R., Astudillo-Defru, N., Bonfils, X., Berdiñas, Z., Ricker, G., Vanderspek, R., Latham, D. W., Seager, S., Winn, J., Jenkins, J. S., Almenara, J. M., Bouchy, F., Delfosse, X., Díaz, M. R., Díaz, R. F., Doyon, R., Figueira, P., Forveille, T., Kurtovic, N. T., Lovis, C., Mayor, M., Menou, K., Morgan, E., Morris, R., Muirhead, P., Murgas, F., Pepe, F., Santos, N. C., Ségransan, D., Smith, J. C., Tenenbaum, P., Torres, G., Udry, S., Vezie, M., Villasenor, J., Université du Québec à Rimouski (UQAR), Universidad de Concepción [Chile], Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Center for Space Research [Cambridge] (CSR), Massachusetts Institute of Technology (MIT), Universidad de Chile, Institut d'Astrophysique de Paris (IAP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université de Montréal (UdeM), Centro de Astrofísica da Universidade do Porto (CAUP), Universidade do Porto [Porto], Observatoire Astronomique de l'Université de Genève (ObsGE), Université de Genève (UNIGE), Boston University [Boston] (BU), Stanford Linear Accelerator Center (SLAC), Stanford University [Stanford], Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Universidade do Porto, SLAC National Accelerator Laboratory (SLAC), and Stanford University

Subjects
planets and satellites: terrestrial planets, stars: low-mass, [SDU]Sciences of the Universe [physics], techniques: radial velocities, Astrophysics::Earth and Planetary Astrophysics, planetary systems, stars: individual: L 98-59
Abstract

International audience; Aims: L 98-59 (TIC 307210830, TOI-175) is a nearby M3 dwarf around which TESS revealed three small transiting planets (0.80, 1.35, 1.57 Earth radii) in a compact configuration with orbital periods shorter than 7.5 days. Here we aim to measure the masses of the known transiting planets in this system using precise radial velocity (RV) measurements taken with the HARPS spectrograph. Methods: We considered both trained and untrained Gaussian process regression models of stellar activity, which are modeled simultaneously with the planetary signals. Our RV analysis was then supplemented with dynamical simulations to provide strong constraints on the planets' orbital eccentricities by requiring long-term stability. Results: We measure the planet masses of the two outermost planets to be 2.42 ± 0.35 and 2.31 ± 0.46 Earth masses, which confirms the bulk terrestrial composition of the former and eludes to a significant radius fraction in an extended gaseous envelope for the latter. We are able to place an upper limit on the mass of the smallest, innermost planet of

Published
2019
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12. Bright Opportunities for Atmospheric Characterization of Small Planets: Masses and Radii of K2-3 b, c, and d and GJ3470 b from Radial Velocity Measurements and Spitzer Transits

Author

Kosiarek, Molly R., Crossfield, Ian J. M., Hardegree-Ullman, Kevin K., Livingston, John H., Benneke, Björn, Henry, Gregory W., Howard, Ward S., Berardo, David, Blunt, Sarah, Fulton, Benjamin J., Hirsch, Lea A., Howard, Andrew W., Isaacson, Howard, Petigura, Erik A., Sinukoff, Evan, Weiss, Lauren, Bonfils, X., Dressing, Courtney D., Knutson, Heather A., Schlieder, Joshua E., Werner, Michael, Gorjian, Varoujan, Krick, Jessica, Morales, Farisa Y., Astudillo-Defru, Nicola, Almenara, J.-M., Delfosse, X., Forveille, T., Lovis, C., Mayor, M., Murgas, F., Pepe, F., Santos, N. C., Udry, S., Corbett, H. T., Fors, Octavi, Law, Nicholas M., Ratzloff, Jeffrey K., del Ser, Daniel, Kosiarek, Molly, Crossfield, Ian, Hardegree-Ullman, Kevin, Livingston, John, Henry, Gregory, Howard, Ward, Fulton, Benjamin, Hirsch, Lea, Howard, Andrew, Petigura, Erik, Dressing, Courtney, Knutson, Heather, Schlieder, Joshua, Morales, Farisa, Law, Nicholas, Ratzloff, Jeffrey, Ser, Daniel del, Département de Physique [Montréal], Université de Montréal [Montréal], Department of Earth and Planetary Science [UC Berkeley] (EPS), University of California [Berkeley], University of California-University of California, Institute for Astronomy [Honolulu], University of Hawai‘i [Mānoa] (UHM), Université de Montréal - UdeM (CANADA), Université de Montréal (UdeM), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Division of Geological and Planetary Sciences [Pasadena], California Institute of Technology (CALTECH), Observatoire Astronomique de l'Université de Genève (ObsGE), Université de Genève (UNIGE), Universidad de Concepción [Chile], Centro de Astrofísica da Universidade do Porto (CAUP), Universidade do Porto [Porto], Department of Astronomy and Astrophysics [UCSC Santa Cruz], University of California [Santa Cruz] (UCSC), MIT Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology (MIT), SRI International [Menlo Park] (SRI), Infrared Processing and Analysis Center (IPAC), Caltech Department of Astronomy [Pasadena], Max-Planck-Institut für Astronomie (MPIA), Max-Planck-Gesellschaft, University of Leeds, Tennessee State University, Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), and Universidade do Porto

Subjects
010504 meteorology & atmospheric sciences, FOS: Physical sciences, Astrophysics, Rotation, Ephemeris, 01 natural sciences, techniques: photometric, Planet, 0103 physical sciences, techniques: radial velocities, Transit (astronomy), 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, Earth and Planetary Astrophysics (astro-ph.EP), Stellar rotation, planets and satellites: composition, Astronomy and Astrophysics, Radial velocity, Stars, Photometry (astronomy), 13. Climate action, Space and Planetary Science, [SDU]Sciences of the Universe [physics], [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Earth and Planetary Astrophysics
Abstract

We report improved masses, radii, and densities for four planets in two bright M-dwarf systems, K2-3 and GJ3470, derived from a combination of new radial velocity and transit observations. Supplementing K2 photometry with follow-up Spitzer transit observations refined the transit ephemerides of K2-3 b, c, and d by over a factor of 10. We analyze ground-based photometry from the Evryscope and Fairborn Observatory to determine the characteristic stellar activity timescales for our Gaussian Process fit, including the stellar rotation period and activity region decay timescale. The stellar rotation signals for both stars are evident in the radial velocity data and are included in our fit using a Gaussian process trained on the photometry. We find the masses of K2-3 b, K2-3 c and GJ3470 b to be 6.48$^{+0.99}_{-0.93}$, 2.14$^{+1.08}_{-1.04}$, and 12.58$^{+1.31}_{-1.28}$ M$_\oplus$ respectively. K2-3 d was not significantly detected and has a 3-$\sigma$ upper limit of 2.80 M$_\oplus$. These two systems are training cases for future TESS systems; due to the low planet densities ($\rho$ $, Comment: 21 pages, 11 figures, accepted to AJ

Published
2019
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13. Radial velocity follow-up of GJ1132 with HARPS

Author

Bonfils, X., Almenara, J.-M., Cloutier, R., Wünsche, A., Astudillo-Defru, N., Berta-Thompson, Z., Bouchy, F., Charbonneau, D., Delfosse, X., Díaz, R. F., Dittmann, J., Doyon, R., Forveille, T., Irwin, J., Lovis, C., Mayor, M., Menou, K., Murgas, F., Newton, E., Pepe, F., Santos, N. C., Udry, S., Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Université du Québec à Rimouski (UQAR), Universidad de Concepción [Chile], Institut d'Astrophysique de Paris (IAP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université de Montréal (UdeM), Université du Texas, Observatoire Astronomique de l'Université de Genève (ObsGE), Université de Genève (UNIGE), Centro de Astrofísica da Universidade do Porto (CAUP), Universidade do Porto [Porto], Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), and Universidade do Porto

Subjects
[SDU]Sciences of the Universe [physics], techniques: radial velocities, stars: late-type, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], planetary systems
Abstract

International audience; The source GJ1132 is a nearby red dwarf known to host a transiting Earth-size planet. After its initial detection, we pursued an intense follow-up with the HARPS velocimeter. We now confirm the detection of GJ1132b with radial velocities alone. We refined its orbital parameters, and in particular, its mass (mb = 1.66 ± 0.23 M⊕), density (ρb = 6.3 ± 1.3 g cm-3), and eccentricity (eb < 0.22; 95%). We also detected at least one more planet in the system. GJ1132c is a super-Earth with period Pc = 8.93 ± 0.01 days and minimum mass mc sinic = 2.64 ± 0.44 M⊕. Receiving about 1.9 times more flux than Earth in our solar system, its equilibrium temperature is that of a temperate planet (Teq = 230-300 K for albedos A = 0.75 - 0.00), which places GJ1132c near the inner edge of the so-called habitable zone. Despite an a priori favorable orientation for the system, Spitzer observations reject most transit configurations, leaving a posterior probability

Published
2018
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14. Discovery of a hot, transiting, Earth-sized planet and a second temperate, non-transiting planet around the M4 dwarf GJ 3473 (TOI-488).

Author

Kemmer, J., Stock, S., Kossakowski, D., Kaminski, A., Molaverdikhani, K., Schlecker, M., Caballero, J. A., Amado, P. J., Astudillo-Defru, N., Bonfils, X., Ciardi, D., Collins, K. A., Espinoza, N., Fukui, A., Hirano, T., Jenkins, J. M., Latham, D. W., Matthews, E. C., Narita, N., and Pallé, E.

Subjects
INNER planets, PLANETARY mass, EMISSION spectroscopy, ASTRONOMICAL transits, PLANETARY orbits, DWARF stars
Abstract

We present the confirmation and characterisation of GJ 3473 b (G 50–16, TOI-488.01), a hot Earth-sized planet orbiting an M4 dwarf star, whose transiting signal (P = 1.1980035 ± 0.0000018 d) was first detected by the Transiting Exoplanet Survey Satellite (TESS). Through a joint modelling of follow-up radial velocity observations with CARMENES, IRD, and HARPS together with extensive ground-based photometric follow-up observations with LCOGT, MuSCAT, and MuSCAT2, we determined a precise planetary mass, Mb = 1.86 ± 0.30 M⊕, and radius, Rb = 1.264 ± 0.050 R⊕. Additionally, we report the discovery of a second, temperate, non-transiting planet in the system, GJ 3473 c, which has a minimum mass, Mc sin i = 7.41 ± 0.91 M⊕, and orbital period, Pc = 15.509 ± 0.033 d. The inner planet of the system, GJ 3473 b, is one of the hottest transiting Earth-sized planets known thus far, accompanied by a dynamical mass measurement, which makes it a particularly attractive target for thermal emission spectroscopy. [ABSTRACT FROM AUTHOR]

Published
2020
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15. Planetary system LHS 1140 revisited with ESPRESSO and TESS.

Author

Lillo-Box, J., Figueira, P., Leleu, A., Acuña, L., Faria, J. P., Hara, N., Santos, N. C., Correia, A. C. M., Robutel, P., Deleuil, M., Barrado, D., Sousa, S., Bonfils, X., Mousis, O., Almenara, J. M., Astudillo-Defru, N., Marcq, E., Udry, S., Lovis, C., and Pepe, F.

Subjects
ASTRONOMICAL transits, ESPRESSO, LOW mass stars, INNER planets, HABITABLE planets, EXTRASOLAR planets, PLANETARY systems
Abstract

Context. LHS 1140 is an M dwarf known to host two transiting planets at orbital periods of 3.77 and 24.7 days. They were detected with HARPS and Spitzer. The external planet (LHS 1140 b) is a rocky super-Earth that is located in the middle of the habitable zone of this low-mass star. All these properties place this system at the forefront of the habitable exoplanet exploration, and it therefore constitutes a relevant case for further astrobiological studies, including atmospheric observations. Aims. We further characterize this system by improving the physical and orbital properties of the known planets, search for additional planetary-mass components in the system, and explore the possibility of co-orbitals. Methods. We collected 113 new high-precision radial velocity observations with ESPRESSO over a 1.5-yr time span with an average photon-noise precision of 1.07 m s−1. We performed an extensive analysis of the HARPS and ESPRESSO datasets and also analyzed them together with the new TESS photometry. We analyzed the Bayesian evidence of several models with different numbers of planets and orbital configurations. Results. We significantly improve our knowledge of the properties of the known planets LHS 1140 b (Pb ~ 24.7 days) and LHS 1140 c (Pc ~ 3.77 days). We determine new masses with a precision of 6% for LHS 1140 b (6.48 ± 0.46 M⊕) and 9% for LHS 1140 c (mc = 1.78 ± 0.17 M⊕). This reduces the uncertainties relative to previously published values by half. Although both planets have Earth-like bulk compositions, the internal structure analysis suggests that LHS 1140 b might be iron-enriched and LHS 1140 c might be a true Earth twin. In both cases, the water content is compatible to a maximum fraction of 10–12% in mass, which is equivalent to a deep ocean layer of 779 ± 650 km for the habitable-zone planet LHS 1140 b. Our results also provide evidence for a new planet candidate in the system (md = 4.8 ± 1.1M⊕) on a 78.9-day orbital period, which is detected through three independent methods. The analysis also allows us to discard other planets above 0.5 M⊕ for periods shorter than 10 days and above 2 M⊕ for periods up to one year. Finally, our co-orbital analysis discards co-orbital planets in the tadpole and horseshoe configurations of LHS 1140 b down to 1 M⊕ with a 95% confidence level (twice better than with the previous HARPS dataset). Indications for a possible co-orbital signal in LHS 1140 c are detected in both radial velocity (alternatively explained by a high eccentricity) and photometric data (alternatively explained by systematics), however. Conclusions. The new precise measurements of the planet properties of the two transiting planets in LHS 1140 as well as the detection of the planet candidate LHS 1140 d make this system a key target for atmospheric studies of rocky worlds at different stellar irradiations. [ABSTRACT FROM AUTHOR]

Published
2020
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16. Confirmation of the radial velocity super-Earth K2-18c with HARPS and CARMENES.

Author

Cloutier, R., Astudillo-Defru, N., Doyon, R., Bonfils, X., Almenara, J.-M., Bouchy, F., Delfosse, X., Forveille, T., Lovis, C., Mayor, M., Menou, K., Murgas, F., Pepe, F., Santos, N. C., Udry, S., and Wünsche, A.

Subjects
RADIAL velocity of stars, STELLAR activity, TIME series analysis, WAVELENGTHS, SAMPLING (Process)
Abstract

In an earlier campaign to characterize the mass of the transiting temperate super-Earth K2-18b with HARPS, a second, non-transiting planet was posited to exist in the system at ~9 days. Further radial velocity follow-up with the CARMENES spectrograph visible channel revealed a much weaker signal at 9 days, which also appeared to vary chromatically and temporally, leading to the conclusion that the origin of the 9-day signal was more likely related to stellar activity than to a planetary presence. Here we conduct a detailed reanalysis of all available RV time-series – including a set of 31 previously unpublished HARPS measurements – to investigate the effects of time-sampling and of simultaneous modelling of planetary plus activity signals on the existence and origin of the curious 9-day signal. We conclude that the 9-day signal is real and was initially seen to be suppressed in the CARMENES data due to a small number of anomalous measurements, although the exact cause of these anomalies remains unknown. Investigation of the signal's evolution in time with wavelength and detailed model comparison reveals that the 9-day signal is most likely planetary in nature. Using this analysis, we reconcile the conflicting HARPS and CARMENES results and measure precise and self-consistent planet masses of mp,b = 8.63 ± 1.35 and mp,c sinic = 5.62 ± 0.84 Earth masses. This work, along with the previously published RV papers on the K2-18 planetary system, highlights the importance of understanding the time-sampling and of modelling the simultaneous planet plus stochastic activity, particularly when searching for sub-Neptune-sized planets with radial velocities. [ABSTRACT FROM AUTHOR]

Published
2019
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17. Extrasolar planets and brown dwarfs around AF-type stars: X. The SOPHIE sample: combining the SOPHIE and HARPS surveys to compute the close giant planet mass-period distribution around AF-type stars.

Author

Borgniet, S., Lagrange, A.-M., Meunier, N., Galland, F., Arnold, L., Astudillo-Defru, N., Beuzit, J.-L., Boisse, I., Bonfils, X., Bouchy, F., Debondt, K., Deleuil, M., Delfosse, X., Desort, M., Díaz, R. F., Eggenberger, A., Ehrenreich, D., Forveille, T., Hébrard, G., and Loeillet, B.

Subjects
BROWN dwarf stars, EXTRASOLAR planets, RADIAL velocity of galaxies, BINARY stars, STELLAR mass
Abstract

Context. The impact of stellar mass on the properties of giant planets is still not fully understood. Main-sequence (MS) stars more massive than the Sun remain relatively unexplored in radial velocity (RV) surveys, due to their characteristics which hinder classical RV measurements. Aims. Our aim is to characterize the close (up to ~2 au) giant planet (GP) and brown dwarf (BD) population around AF MS stars and compare this population to stars with different masses. Methods. We used the SOPHIE spectrograph located on the 1.93 m telescope at Observatoire de Haute-Provence to observe 125 northern, MS AF dwarfs. We used our dedicated SAFIR software to compute the RV and other spectroscopic observables. We characterized the detected substellar companions and computed the GP and BD occurrence rates combining the present SOPHIE survey and a similar HARPS survey. Results. We present new data on two known planetary systems around the F5-6V dwarfs HD 16232 and HD 113337. For the latter, we report an additional RV variation that might be induced by a second GP on a wider orbit. We also report the detection of 15 binaries or massive substellar companions with high-amplitude RV variations or long-term RV trends. Based on 225 targets observed with SOPHIE and/or HARPS, we constrain the BD frequency within 2–3 au around AF stars to be below 4% (1σ). For Jupiter-mass GPs within 2–3 au (periods ≤103 days), we find the occurrence rate to be 3.7−1+3 $3.7_{-1}^{+3}$ 3.7 − 1 + 3 % around AF stars with masses <1.5 M⊙, and to be ≤6% (1σ) around AF stars with masses >1.5 M⊙. For periods shorter than 10 days, we find the GP occurrence rate to be below 3 and 4.5% (1σ), respectively. Our results are compatible with the GP frequency reported around FGK dwarfs and are compatible with a possible increase in GP orbital periods with stellar mass as predicted by formation models. [ABSTRACT FROM AUTHOR]

Published
2019
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18. Eyes on K2-3: A system of three likely sub-Neptunes characterized with HARPS-N and HARPS.

Author

Damasso, M., Bonomo, A. S., Astudillo-Defru, N., Bonfils, X., Malavolta, L., Sozzetti, A., Lopez, E., Zeng, L., Haywood, R. D., Irwin, J. M., Mortier, A., Vanderburg, A., Maldonado, J., Lanza, A. F., Affer, L., Almenara, J.-M., Benatti, S., Biazzo, K., Bignamini, A., and Borsa, F.

Subjects
M stars, DWARF stars, RADIAL velocity of stars, STELLAR rotation, MASS measurement
Abstract

Context. M-dwarf stars are promising targets for identifying and characterizing potentially habitable planets. K2-3 is a nearby (45 pc), early-type M dwarf hosting three small transiting planets, the outermost of which orbits close to the inner edge of the stellar (optimistic) habitable zone. The K2-3 system is well suited for follow-up characterization studies aimed at determining accurate masses and bulk densities of the three planets. Aims. Using a total of 329 radial velocity measurements collected over 2.5 years with the HARPS-N and HARPS spectrographs and a proper treatment of the stellar activity signal, we aim to improve measurements of the masses and bulk densities of the K2-3 planets. We use our results to investigate the physical structure of the planets. Methods. We analysed radial velocity time series extracted with two independent pipelines using Gaussian process regression. We adopted a quasi-periodic kernel to model the stellar magnetic activity jointly with the planetary signals. We used Monte Carlo simulations to investigate the robustness of our mass measurements of K2-3 c and K2-3 d, and to explore how additional high-cadence radial velocity observations might improve these values. Results. Even though the stellar activity component is the strongest signal present in the radial velocity time series, we are able to derive masses for both planet b (Mb = 6.6 ± 1.1 M⊕) and planet c (Mc = 3.1−1.2+1.3 M⊕). The Doppler signal from K2-3 d remains undetected, likely because of its low amplitude compared to the radial velocity signal induced by the stellar activity. The closeness of the orbital period of K2-3 d to the stellar rotation period could also make the detection of the planetary signal complicated. Based on our ability to recover injected signals in simulated data, we tentatively estimate the mass of K2-3 d to be Md = 2.7−0.8+1.2 M⊕ M⊕. These mass measurements imply that the bulk densities and therefore the interior structures of the three planets may be similar. In particular, the planets may either have small H/He envelopes (<1%) or massive water layers, with a water content ≥50% of their total mass, on top of rocky cores. Placing further constraints on the bulk densities of K2-3 c and d is difficult; in particular, we would not have been able to detect the Doppler signal of K2-3 d even by adopting a semester of intense, high-cadence radial velocity observations with HARPS-N and HARPS. [ABSTRACT FROM AUTHOR]

Published
2018
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19. SOPHIE velocimetry of Kepler transit candidates XVIII. Radial velocity confirmation, absolute masses and radii, and origin of the Kepler-419 multiplanetary system.

Author

Almenara, J. M., R. F. Díaz, Hébrard, G., Mardling, R., Damiani, C., Santerne, A., Bouchy, F., C. Barros, S. C., Boisse, I., Bonfils, X., Bonomo, A. S., Courcol, B., Demangeon, O., Deleuil, M., Rey, J., Udry, S., and Wilson, P. A.

Subjects
PLANETARY systems, VELOCIMETRY, SPECTROGRAPHS, ASTRONOMICAL photometry, PLANETARY orbits
Abstract

Kepler-419 is a planetary system discovered by the Kepler photometry which is known to harbour two massive giant planets: an inner 3 MJ transiting planet with a 69.8-day period, highly eccentric orbit, and an outer 7.5 MJ non-transiting planet predicted from the transit-timing variations (TTVs) of the inner planet b to have a 675-day period, moderately eccentric orbit. Here we present new radial velocity (RV) measurements secured over more than two years with the SOPHIE spectrograph, where both planets are clearly detected. The RV data is modelled together with the Kepler photometry using a photodynamical model. The inclusion of velocity information breaks the MR−3 degeneracy inherent in timing data alone, allowing us to measure the absolute stellar and planetary radii and masses. With uncertainties of 12 and 13% for the stellar and inner planet radii, and 35, 24, and 35% for the masses of the star, planet b, and planet c, respectively, these measurements are the most precise to date for a single host star system using this technique. The transiting planet mass is determined at better precision than the star mass. This shows that modelling the radial velocities and the light curve together in systems of dynamically interacting planets provides a way of characterising both the star and the planets without being limited by knowledge of the star. On the other hand, the period ratio and eccentricities place the Kepler-419 system in a sweet spot; had around twice as many transits been observed, the mass of the transiting planet could have been measured using its own TTVs. Finally, the origin of the Kepler-419 system is discussed. We show that the system is near a coplanar high-eccentricity secular fixed point, related to the alignment of the orbits, which has prevented the inner orbit from circularising. For most other relative apsidal orientations, planet b’s orbit would be circular with a semi-major axis of 0.03 au. This suggests a mechanism for forming hot Jupiters in multiplanetary systems without the need of high mutual inclinations. [ABSTRACT FROM AUTHOR]

Published
2018
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20. A temperate exo-Earth around a quiet M dwarf at 3.4 parsec.

Author

Bonfils, X., Astudillo-Defru, N., Díaz, R., Almenara, J.-M., Forveille, T., Bouchy, F., Delfosse, X., Lovis, C., Mayor, M., Murgas, F., Pepe, F., C. Santos, N., Ségransan, D., Udry, S., and Wünsche, A.

Subjects
*DWARF stars, *EARTH (Planet), *PARSEC, *TEMPERATE climate, *LARGE astronomical telescopes
Abstract

The combination of high-contrast imaging and high-dispersion spectroscopy, which has successfully been use to detect the atmosphere of a giant planet, is one of the most promising potential probes of the atmosphere of Earth-size worlds. The forthcoming generation of extremely large telescopes (ELTs) may obtain sufficient contrast with this technique to detect O2 in the atmosphere of those worlds that orbit low-mass M dwarfs. This is strong motivation to carry out a census of planets around cool stars for which habitable zones can be resolved by ELTs, i.e. for M dwarfs within ~5 parsec. Our HARPS survey has been a major contributor to that sample of nearby planets. Here we report on our radial velocity observations of Ross 128 (Proxima Virginis, GJ447, HIP 57548), an M4 dwarf just 3.4 parsec away from our Sun. This source hosts an exo-Earth with a projected mass msin i = 1:35 M⊕ and an orbital period of 9.9 days. Ross 128 b receives less than 1.5 times as much flux as Earth from the Sun and its equilibrium ranges in temperature between 269 K for an Earth-like albedo and 213 K for a Venus-like albedo. Recent studies place it close to the inner edge of the conventional habitable zone. An 80-day long light curve from K2 campaign C01 demonstrates that Ross 128 b does not transit. Together with the All Sky Automated Survey (ASAS) photometry and spectroscopic activity indices, the K2 photometry shows that Ross 128 rotates slowly and has weak magnetic activity. In a habitability context, this makes survival of its atmosphere against erosion more likely. Ross 128 b is the second closest known exo-Earth, after Proxima Centauri b (1.3 parsec), and the closest temperate planet known around a quiet star. The 15 mas planet-star angular separation at maximum elongation will be resolved by ELTs (>3λ=D) in the optical bands of O2. [ABSTRACT FROM AUTHOR]

Published
2018
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21. The HARPS search for southern extra-solar planets: XLII. A system of Earth-mass planets around the nearby M dwarf YZ Ceti.

Author

Astudillo-Defru, N., Díaz, R. F., Bonfils, X., Almenara, J. M., Delisle, J.-B., Bouchy, F., Delfosse, X., Forveille, T., Lovis, C., Mayor, M., Murgas, F., Pepe, F., Santos, N. C., Ségransan, D., Udry, S., and Wünsche, A.

Subjects
EXTRASOLAR planets, DWARF stars, LOW mass stars, PLANETARY orbits, RADIAL velocity of stars
Abstract

Exoplanet surveys have shown that systems with multiple low-mass planets on compact orbits are common. Except for a few cases, however, the masses of these planets are generally unknown. At the very end of the main sequence, host stars have the lowest mass and hence offer the largest reflect motion for a given planet. In this context, we monitored the low-mass (0.13 M⊙) M dwarf YZ Cet (GJ 54.1, HIP 5643) intensively and obtained radial velocities and stellar-activity indicators derived from spectroscopy and photometry, respectively. We find strong evidence that it is orbited by at least three planets in compact orbits (POrb = 1.97, 3.06, 4.66 days), with the inner two near a 2:3 mean-motion resonance. The minimum masses are comparable to the mass of Earth (M sin i = 0.75 ± 0.13, 0.98 ± 0.14, and 1.14 ± 0.17 M⊕), and they are also the lowest masses measured by radial velocity so far. We note the possibility for a fourth planet with an even lower mass of M sin i = 0.472 ± 0.096 M⊕ at POrb = 1.04 days. An n-body dynamical model is used to place further constraints on the system parameters. At 3.6 parsecs, YZ Cet is the nearest multi-planet system detected to date. [ABSTRACT FROM AUTHOR]

Published
2017
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22. The HARPS search for southern extra-solar planets: XLI. A dozen planets around the M dwarfs GJ 3138, GJ 3323, GJ 273, GJ 628, and GJ 3293.

Author

Astudillo-Defru, N., Forveille, T., Bonfils, X., Ségransan, D., Bouchy, F., Delfosse, X., Lovis, C., Mayor, M., Murgas, F., Pepe, F., Santos, N. C., Udry, S., and Wünsche, A.

Subjects
EXTRASOLAR planets, STELLAR activity, PLANETS, ALPHA Centauri, HABITABLE planets, ORIGIN of planets
Abstract

Context. Low-mass stars are currently the best targets when searching for rocky planets in the habitable zone of their host star. Over the last 13 yr, precise radial velocities measured with the HARPS spectrograph have identified over a dozen super-Earths and Earth-mass planets (msin i ≤ 10 M⊙) around M dwarfs, with a well-understood selection function. This well-defined sample provides information on their frequency of occurrence and on the distribution of their orbital parameters, and therefore already constrains our understanding of planetary formation. The subset of these low-mass planets that were found within the habitable zone of their host star also provide prized targets for future searches of atmospheric biomarkers. Aims. We are working to extend this planetary sample to lower masses and longer periods through dense and long-term monitoring of the radial velocity of a small M dwarf sample. Methods. We obtained large numbers of HARPS spectra for the M dwarfs GJ 3138, GJ 3323, GJ 273, GJ 628, and GJ 3293, from which we derived radial velocities (RVs) and spectroscopic activity indicators. We searched for variabilities, periodicities, Keplerian modulations, and correlations, and attribute the radial-velocity variations to combinations of planetary companions and stellar activity. Results. We detect 12 planets, 9 of which are new with masses ranging from 1.17 to 10.5 M⊙. These planets have relatively short orbital periods (P < 40 d), except for two that have periods of 217.6 and 257.8 days. Among these systems, GJ 273 harbor two planets with masses close to the Earth's. With a distance of only 3.8 parsec, GJ 273 is the second nearest known planetary system - after Proxima Centauri - with a planet orbiting the circumstellar habitable zone. [ABSTRACT FROM AUTHOR]

Published
2017
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23. The SOPHIE search for northern extrasolar planets: XII. Three giant planets suitable for astrometric mass determination with Gaia.

Author

Rey, J., Hébrard, G., Bouchy, F., Bourrier, V., Boisse, I., Santos, N. C., Arnold, L., Astudillo-Defru, N., Bonfils, X., Borgniet, S., Courcol, B., Deleuil, M., Delfosse, X., Demangeon, O., Díaz, R. F., Ehrenreich, D., Forveille, T., Marmier, M., Moutou, C., and Pepe, F.

Subjects
EXTRASOLAR planets, ASTROMETRY, RADIAL velocity of stars, SPECTROGRAPHS
Abstract

We present new radial velocity measurements for three low-metallicity solar-like stars observed with the SOPHIE spectrograph and its predecessor ELODIE, both installed at the 193 cm telescope of the Haute-Provence Observatory, allowing the detection and characterization of three new giant extrasolar planets in intermediate periods of 1.7 to 3.7 yr. All three stars, HD 17674, HD 42012 and HD 29021 present single giant planetary companions with minimum masses between 0.9 and 2.5 MJup. The range of periods and masses of these companions, along with the distance of their host stars, make them good targets to look for astrometric signals over the lifetime of the new astrometry satellite Gaia. We discuss the preliminary astrometric solutions obtained from the first Gaia data release. [ABSTRACT FROM AUTHOR]

Published
2017
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24. The HARPS search for southern extra-solar planets XXXVI. Planetary systems and stellar activity of the M dwarfs GJ 3293, GJ 3341, and GJ 3543.

Author

Astudillo-Defru, N., Bonfils, X., Delfosse, X., Ségransan, D., Forveille, T., Bouchy, F., Gillon, M., Lovis, C., Mayor, M., Neves, V., Pepe, F., Perrier, C., Queloz, D., Rojo, P., Santos, N. C., and Udry, S.

Subjects
*PLANETS, *STELLAR activity, *LOW mass stars, *ASTRONOMICAL observations, *ARTIFICIAL satellites in astronomy
Abstract

Context. Planetary companions of a fixed mass induce reflex motions with a larger amplitude around lower-mass stars, which adds to making M dwarfs excellent targets for extra-solar planet searches. The most recent velocimeters with a stability of ~1 ms-1 can detect very low-mass planets out to the habitable zone of these stars. Low-mass small planets are abundant around M dwarfs, and most of the known potentially habitable planets orbit one of these cool stars. Aims. Our M-dwarf radial velocity monitoring with HARPS on the ESO 3.6 m telescope at La Silla observatory makes a major contribution to this sample. Methods. We present here dense radial velocity (RV) time series for three M dwarfs observed over ~five years: GJ 3293 (0.42 M⊕), GJ 3341 (0.47 M⊕), and GJ 3543 (0.45 M⊕). We extracted these RVs through minimum χ2-matching of each spectrum against a stack of all observed spectra for the same star that has a high signal-to-noise ratio. We then compared potential orbital signals against several stellar activity indicators to distinguish the Keplerian variations induced by planets from the spurious signals that result from rotational modulation of stellar surface inhomogeneities and from activity cycles. Results. Two Neptune-mass planets - m sin(i) = 1:4 ± 0:1 and 1:3 ± 0:1Mnept - orbit GJ 3293 with periods P = 30:60 ± 0:02 d and P = 123:98 ± 0:38 d, possibly together with a super-Earth - m sin(i) ~ 7:9 ± 1:4 M⊕ - with period P = 48:14 ± 0:12 d. A super-Earth - m sin(i) ~ 6:1 M⊕ - orbits GJ 3341 with P = 14:207 ± 0:007 d. The RV variations of GJ 3543, on the other hand, reflect its stellar activity rather than planetary signals. [ABSTRACT FROM AUTHOR]

Published
2015
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25. A global analysis of Spitzer and new HARPS data confirms the loneliness and metal-richness of GJ 436 b.

Author

Lanotte, A. A., Gillon, M., Demory, B.-O., Fortney, J. J., Astudillo, N., Bonfils, X., Magain, P., Delfosse, X., Forveille, T., Lovis, C., Mayor, M., Neves, V., Pepe, F., Queloz, D., Santos, N., and Udry, S.

Subjects
RADIAL velocity of stars, STARS, PLANETARY research, ASTRONOMICAL research, ASTROPHYSICS research
Abstract

Context. GJ 436b is one of the few transiting warm Neptunes for which a detailed characterisation of the atmosphere is possible, whereas its non-negligible orbital eccentricity calls for further investigation. Independent analyses of several individual datasets obtained with Spitzer have led to contradicting results attributed to the different techniques used to treat the instrumental effects. Aims. We aim at investigating these previous controversial results and developing our knowledge of the system based on the full Spitzer photometry dataset combined with new Doppler measurements obtained with the HARPS spectrograph. We also want to search for additional planets. Methods. We optimise aperture photometry techniques and the photometric deconvolution algorithm DECPHOT to improve the data reduction of the Spitzer photometry spanning wavelengths from 3-24 μm. Adding the high-precision HARPS radial velocity data, we undertake a Bayesian global analysis of the system considering both instrumental and stellar e ects on the flux variation. Results. We present a refined radius estimate of RP = 4:10 ± 0:16 R☉, mass MP = 25:4 ± 2:1 M☉, and eccentricity e = 0:162 ± 0:004 for GJ 436b. Our measured transit depths remain constant in time and wavelength, in disagreement with the results of previous studies. In addition, we find that the post-occultation flare-like structure at 3.6 μm that led to divergent results on the occultation depth measurement is spurious. We obtain occultation depths at 3.6, 5.8, and 8.0 μm that are shallower than in previous works, in particular at 3.6 μm. However, these depths still appear consistent with a metal-rich atmosphere depleted in methane and enhanced in CO/CO2, although perhaps less than previously thought. We could not detect a significant orbital modulation in the 8 μm phase curve. We find no evidence of a potential planetary companion, stellar activity, or a stellar spin-orbit misalignment. Conclusions. Recent theoretical models invoking high-metallicity atmospheres for warm Neptunes are a reasonable match to our results, but we encourage new modelling efforts based on our revised data. Future observations covering a wide wavelength range of GJ 436b and other Neptune-class exoplanets will further illuminate their atmosphere properties, whilst future accurate radial velocity measurements might explain the eccentricity. [ABSTRACT FROM AUTHOR]

Published
2014
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26. The SOPHIE search for northern extrasolar planets VI. Three new hot Jupiters in multi-planet extrasolar systems.

Author

Moutou, C., Hébrard, G., Bouchy, F., Arnold, L., Santos, N. C., Astudillo-Defru, N., Boisse, I., Bonfils, X., Borgniet, S., Delfosse, X., Díaz, R. F., Ehrenreich, D., Forveille, T., Gregorio, J., Labrevoir, O., Lagrange, A. M., Montagnier, G., Montalto, M., Pepe, F., and Sahlmann, J.

Subjects
HOT Jupiters, EXTRASOLAR planets, RADIAL velocity of stars, PHOTOMETRIC stereo
Abstract

We present high-precision radial-velocity measurements of three solar-type stars: HD13908, HD159243, and HIP 91258. The observations were made with the SOPHIE spectrograph at the 1.93 m telescope of the Observatoire de Haute-Provence (France). They show that these three bright stars host exoplanetary systems composed of at least two companions. HD13908 b is a planet with a minimum mass of 0.865 ± 0.035 MJup on a circular orbit with a period of 19.382 ± 0.006 days. There is an outer massive companion in the system with a period of 931 ± 17 days, e = 0.12 ± 0.02, and a minimum mass of 5.13 ± 0.25 MJup. The star HD159243 also has two detected companions with respective masses, periods, and eccentricities of Mp= 1.13 ± 0.05 and 1.9 ± 0.13 MJup, P = 12.620 ± 0.004 and 248.4 ± 4.9 days, and e = 0.02 ± 0.02 and 0.075 ± 0.05. Finally, the star HIP 91258 has a planetary companion with a minimum mass of 1.068 ± 0.038 MJup, an orbital period of 5.0505 ± 0.0015 days, and a quadratic trend indicating an outer planetary or stellar companion that is as yet uncharacterized. The planet-hosting stars HD13908, HD159243, and HIP 91258 are main-sequence stars of spectral types F8V, G0V, and G5V, respectively, with moderate activity levels. HIP 91258 is slightly over-metallic, while the other two stars have solar-like metallicity. The three systems are discussed in the frame of formation and dynamical evolution models of systems composed of several giant planets. [ABSTRACT FROM AUTHOR]

Published
2014
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27. Extrasolar planets and brown dwarfs around A-F type stars.

Author

Borgniet, S., Boisse, I., Lagrange, A.-M., Bouchy, F., Arnold, L., Díaz, R. F., Galland, F., Delorme, P., Hébrard, G., Santerne, A., Ehrenreich, D., Ségransan, D., Bonfils, X., Delfosse, X., Santos, N. C., Forveille, T., Moutou, C., Udry, S., Eggenberger, A., and Pepe, F.

Subjects
EXTRASOLAR planets, BROWN dwarf stars, ASTRONOMICAL instruments, ASTRONOMICAL photography, QUADRATIC differentials
Abstract

Aims. In the context of the search for extrasolar planets and brown dwarfs around early-type main-sequence stars we present the detection of a giant planet around the young F-type star HD113337. We estimated the age of the system to be 150-50+100 Myr. Interestingly, an infrared excess attributed to a cold debris disk was previously detected around this star. Methods. We used the SOPHIE spectrograph on the 1.93m telescope at Observatoire de Haute-Provence to obtain ~300 spectra over six years. We used our tool dedicated to the spectra analysis of A and F stars to derive the radial velocity variations. Results. The data reveal a period of 324.0-3.3+1.7 days that we attribute to a giant planet with a minimum mass of 2.83 ± 0.24 MJup in an eccentric orbit with e = 0.46 ± 0.04. A long-term quadratic drift, which we assign to be probably of stellar origin, is superimposed on the Keplerian solution. [ABSTRACT FROM AUTHOR]

Published
2014
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28. The HARPS search for southern extra-solar planets.

Author

Bonfils, X., Lo Curto, G., Correia, A. C. M., Laskar, J., Udry, S., Delfosse, X., Forveille, T., Astudillo-Defru, N., Benz, W., Bouchy, F., Gillon, M., Hébrard, G., Lovis, C., Mayor, M., Moutou, C., Naef, D., Neves, V., Pepe, F., Perrier, C., and Queloz, D.

Subjects
*EXTRASOLAR planets, *VELOCIMETERS, *STARS with planets, *HABITABLE zone (Outer space), *STELLAR activity, *HABITABLE planets, *EARTH (Planet)
Abstract

The meter-per-second precision achieved by today's velocimeters enables us to search for 1-10 M⊕ planets in the habitable zone of cool stars. This paper reports on the detection of three planets orbiting GJ 163 (HIP 19394), a M3 dwarf monitored by our ESO/HARPS search for planets. We made use of the HARPS spectrograph to collect 150 radial velocities of GJ 163 over a period of eight years. We searched the radial-velocity time series for coherent signals and found five distinct periodic variabilities. We investigated the stellar activity and called into question the planetary interpretation for two signals. Before more data can be acquired we concluded that at least three planets are orbiting GJ 163. They have orbital periods of Pb = 8:632 ± 0:002, Pc = 25:63 ± 0:03, and Pd = 604 ± 8 days and minimum masses m sin i = 10:6 ± 0:6, 6:8 ± 0:9, and 29 ± 3 M⊕, respectively. We hold our interpretations for the two additional signals with periods P(e) = 19:4 and P(f) = 108 days. The inner pair presents an orbital period ratio of 2:97, but a dynamical analysis of the system shows that it lays outside the 3:1 mean motion resonance. The planet GJ 163c, in particular, is a super-Earth with an equilibrium temperature of Teq = (302 ± 10)(1 - A)1/4 K and may lie in the so-called habitable zone for albedo values (A = 0:34-0:89) moderately higher than that of Earth (A⊕ = 0:2-0:3). [ABSTRACT FROM AUTHOR]

Published
2013
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29. SOAP-T: a tool to study the light curve and radial velocity of a system with a transiting planet and a rotating spotted star.

Author

Oshagh, M., Boisse, I., Boué, G., Montalto, M., Santos, N. C., Bonfils, X., and Haghighipour, N.

Subjects
RADIAL velocity of stars, RADIAL velocity of galaxies, STELLAR rotation, ROTATIONAL motion, STAR observations, ASTRONOMICAL observations
Abstract

We present an improved version of SOAP named "SOAP-T", which can generate the radial velocity variations and light curves for systems consisting of a rotating spotted star with a transiting planet. This tool can be used to study the anomalies inside transit light curves and the Rossiter-McLaughlin effect, to better constrain the orbital configuration and properties of planetary systems and the active zones of their host stars. Tests of the code are presented to illustrate its performance and to validate its capability when compared with analytical models and real data. Finally, we apply SOAP-T to the active star, HAT-P-11, observed by the NASA Kepler space telescope and use this system to discuss the capability of this tool in analyzing light curves for the cases where the transiting planet overlaps with the star's spots. [ABSTRACT FROM AUTHOR]

Published
2013
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30. How the planetary research helps to the stellar dynamo understanding.

Author

Boisse, I., Oshagh, M., Lovis, C., Santos, N. C., Dumusque, X., Bonfils, X., Montalto, M., and Boué, G.

Abstract

Most of the exoplanet science is dependent on the stellar knowledge. One of them that has to be understood is the magnetic activity when we search for planets with radial velocity or photometry measurements. The main shape of stellar activity and spots properties have to be understood, for example, to choose the best targets to search for low-mass planets in the habitable zone or to derive the accurate parameters of a planetary system. With that aim, we show in this presentation how these studies lead to give clues on spots latitudes and on the long term variation of stellar activity. The properties of magnetic activity on the low rotators solar-type stars are not easily reachable by other techniques (spectropolarimetry or Doppler imaging) and these studies should be used to constrain theories of stellar dynamo. [ABSTRACT FROM PUBLISHER]

Published
2012
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31. Stellar Variabilities: Challenges for the Detection and Characterization of Exoplanets.

Author

Boisse, I., Dumusque, X., Santos, N. C., Oshagh, M., Bonfils, X., Montalto, M., Boué, G., and Lovis, C.

Abstract

The photometric and RV techniques, although extremely efficient to detect and characterize planets, are, however, indirect techniques (as well as astrometry). Phenomena such as stellar pulsation, inhomogeneous convection, spots or magnetic cycles can prevent us from finding planets or they might degrade the parameters estimation. We will consider the challenges related to the knowledge of stellar activity for the next decade: detect telluric planets in the habitable zone of their stars (from G to M dwarfs), understand the activity in the low-mass end of M dwarf (on which will focus future near-infrared high-resolution spectrograph like SPIRou or CARMENES), limitation to the process of summing several transit observations (in order to characterize the atmospheric components) due to the variability of stellar activity (from the ground or with Spitzer or JWST), as well as the methods proposed and used to overcome this issue. [ABSTRACT FROM PUBLISHER]

Published
2012
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32. The frequency of giant planets around metal-poor stars.

Author

Mortier, A., Santos, N. C., Sozzetti, A., Mayor, M., Latham, D., Bonfils, X., and Udry, S.

Subjects
EXTRASOLAR planets, SPECTROGRAPHS, STARS, FREQUENCY meters, JUPITER (Planet)
Abstract

Context. The discovery of about 700 extrasolar planets, so far, has lead to the first statistics concerning extrasolar planets. The presence of giant planets seems to depend on stellar metallicity and mass. For example, they are more frequent around metal-rich stars, with an exponential increase in planet occurrence rates with metallicity. Aims. We analyzed two samples of metal-poor stars (-2.0 ≤ [Fe/H] ≤ 0.0) to see if giant planets are indeed rare around these objects. Radial velocity datasets were obtained with two different spectrographs (HARPS and HIRES). Detection limits for these data, expressed in minimum planetary mass and period, are calculated. These produce trustworthy numbers for the planet frequency. Methods. A general Lomb-Scargle (GLS) periodogram analysis was used together with a bootstrapping method to produce the detection limits. Planet frequencies were calculated based on a binomial distribution function within metallicity bins. Results. Almost all hot Jupiters and most giant planets should have been found in these data. Hot Jupiters around metal-poor stars have a frequency lower than 1.0% at one sigma. Giant planets with periods up to 1800 days, however, have a higher frequency of fp = 2.63+2.5 -0.8%. Taking into account the different metallicities of the stars, we show that giant planets appear to be very frequent ( fp = 4.48+4.04 -1.38%) around stars with [Fe/H] > -0.7, while they are rare around stars with [Fe/H] ≤ -0.7 (≤2.36% at one sigma). Conclusions. Giant planet frequency is indeed a strong function of metallicity, even in the low-metallicity tail. However, the frequencies are most likely higher than previously thought [ABSTRACT FROM AUTHOR]

Published
2012
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33. Long-term magnetic activity of a sample of M-dwarf stars from the HARPS program II. Activity and radial velocity.

Author

Gomes da Silva, J., Santos, N. C., Bonfils, X., Delfosse, X., Forveille, T., Udry, S., Dumusque, X., and Lovis, C.

Subjects
DWARF stars, COSMIC magnetic fields, EXTRASOLAR planets, STARS, ASTRONOMY
Abstract

Owing to their low mass and luminosity, M dwarfs are ideal targets if one hopes to find low-mass planets similar to Earth using the radial velocity (RV) method. However, stellar magnetic cycles could add noise or even mimic the RV signal of a long-period companion. We extend our previous study of the correlation between activity cycles and long-term RV variations for K dwarfs to the lower-end of the main sequence. Our objective is to detect any correlations between long-term activity variations and the observed RV of a sample of M dwarfs. We use a sample of 27 M-dwarfs with a median observational timespan of 5.9 years. The cross-correlation function (CCF) with its parameters RV, bisector inverse slope (BIS), full width at half maximum (FWHM), and contrast are computed from the HARPS spectrum. The activity index is derived using the Na i D doublet. These parameters are compared with the activity level of the stars to search for correlations. We detect RV variations up to ∼5 ms-1 that we can attribute to activity cycle effects. However, only 36% of the stars with long-term activity variability appear to have had their RV affected by magnetic cycles, on the typical timescale of ∼6 years. Therefore, we suggest a careful analysis of activity data when searching for extrasolar planets using long-timespan RV data. [ABSTRACT FROM AUTHOR]

Published
2012
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34. The SOPHIE search for northern extrasolar planets: IV. Massive companions in the planet-brown dwarf boundary.

Author

Díaz, R. F., Santerne, A., Sahlmann, J., Hébrard, G., Eggenberger, A., Santos, N. C., Moutou, C., Arnold, L., Boisse, I., Bonfils, X., Bouchy, F., Delfosse, X., Desort, M., Ehrenreich, D., Forveille, T., Lagrange, A.-M., Lovis, C., Pepe, F., Perrier, C., and Queloz, D.

Subjects
EXTRASOLAR planets, BROWN dwarf stars, PLANETS, ASTRONOMICAL photography, ORBITS (Astronomy)
Abstract

Context. The mass domain where massive extrasolar planets and brown dwarfs lie is still poorly understood. Indeed, not even a clear dividing line between massive planets and brown dwarfs has been established yet. This is partly because these objects are very scarce in close orbits around solar-type stars, the so-called brown dwarf desert. Owing to this, it has proven difficult to set up a strong observational base with which to compare models and theories of formation and evolution. Aims. We search to increase the current sample of massive sub-stellar objects with precise orbital parameters, and to constrain the true mass of detected sub-stellar candidates. Methods. The initial identification of sub-stellar candidates was made using precise radial velocity measurements obtained with the SOPHIE spectrograph at the 1.93-m telescope of the Haute-Provence Observatory. Subsequent characterisation of these candidates, with the principal aim of identifying stellar companions in low-inclination orbits, was made by means of different spectroscopic diagnostics such as the measurement of the bisector velocity span and the study of the correlation mask effect. With this objective, we also employed astrometric data from the Hipparcos mission, and a novel method of simulating stellar cross-correlation functions. Results. Seven new objects with minimum masses between ∼10 MJup and ∼90 MJup are detected. Out of these, two are identified as low-mass stars in low-inclination orbits, and two others have masses below the theoretical deuterium-burning limit, and are therefore planetary candidates. The remaining three are brown dwarf candidates; the current upper limits for their the masses do not allow us to conclude on their nature. Additionally, we have improved the parameters of an already-known brown dwarf (HD 137510b), confirmed by astrometry. [ABSTRACT FROM AUTHOR]

Published
2012
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