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1. NGTS clusters survey – III. A low-mass eclipsing binary in the Blanco 1 open cluster spanning the fully convective boundary

Author

Samantha Thompson, Sarah L. Casewell, Maximiliano Moyano, Maximilian N. Günther, Daniel Sebastian, Jose I. Vines, Rosanna H. Tilbrook, P. P. Pedersen, Michael R. Goad, Samuel Gill, Jack S. Acton, Laetitia Delrez, Didier Queloz, Matthew R. Burleigh, Amaury H. M. J. Triaud, James S. Jenkins, Peter J. Wheatley, C. Murray, David Anderson, Beth A. Henderson, Elsa Ducrot, Joshua T. Briegal, Gareth Smith, Georgina Dransfield, Edward Gillen, Lynne A. Hillenbrand, Michaël Gillon, Emmanuel Jehin, Douglas R. Alves, and Daniel Bayliss

Subjects
Physics, 010308 nuclear & particles physics, FOS: Physical sciences, Boundary (topology), Binary number, Astronomy and Astrophysics, Astrophysics, Light curve, 01 natural sciences, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, 0103 physical sciences, Spectral energy distribution, Circular orbit, Low Mass, 010303 astronomy & astrophysics, Stellar evolution, Solar and Stellar Astrophysics (astro-ph.SR), QB, Open cluster
Abstract

We present the discovery and characterisation of an eclipsing binary identified by the Next Generation Transit Survey in the $\sim$115 Myr old Blanco 1 open cluster. NGTS J0002-29 comprises three M dwarfs: a short-period binary and a companion in a wider orbit. This system is the first well-characterised, low-mass eclipsing binary in Blanco 1. With a low mass ratio, a tertiary companion and binary components that straddle the fully convective boundary, it is an important benchmark system, and one of only two well-characterised, low-mass eclipsing binaries at this age. We simultaneously model light curves from NGTS, TESS, SPECULOOS and SAAO, radial velocities from VLT/UVES and Keck/HIRES, and the system's spectral energy distribution. We find that the binary components travel on circular orbits around their common centre of mass in $P_{\rm orb} = 1.09800524 \pm 0.00000038$ days, and have masses $M_{\rm pri}=0.3978\pm 0.0033$ M$_{\odot}$ and $M_{\rm sec}=0.2245\pm 0.0018$ M$_{\odot}$, radii $R_{\rm pri}=0.4037\pm 0.0048$ R$_{\odot}$ and $R_{\rm sec}=0.2759\pm 0.0055$ R$_{\odot}$, and effective temperatures $T_{\rm pri}=3372\,^{+44}_{-37}$ K and $T_{\rm sec}=3231\,^{+38}_{-31}$ K. We compare these properties to the predictions of seven stellar evolution models, which typically imply an inflated primary. The system joins a list of 19 well-characterised, low-mass, sub-Gyr, stellar-mass eclipsing binaries, which constitute some of the strongest observational tests of stellar evolution theory at low masses and young ages., 21 pages, 9 figures. Accepted for publication in MNRAS

Published
2021
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2. NGTS-19b: a high-mass transiting brown dwarf in a 17-d eccentric orbit

Author

Jack S. Acton, Stéphane Udry, Nolan Grieves, Douglas R. Alves, Matthew R. Burleigh, Edward M. Bryant, Sarah L. Casewell, Samuel Gill, James A. G. Jackman, Maximiliano Moyano, James S. Jenkins, David R. Anderson, Monika Lendl, Hannah L. Worters, Szilard Csizmadia, Philipp Eigmüller, Simon Hodgkin, Michael R. Goad, Fran cois Bouchy, Richard P. Nelson, Richard G. West, Maximilian N. Günther, James McCormac, Alexis M. S. Smith, Peter J. Wheatley, H. Breytenbach, Matthew P. Battley, Ramotholo Sefako, Daniel Bayliss, Beth A. Henderson, Jessymol K. Thomas, Jose I. Vines, Rosanna H. Tilbrook, M. Stalport, Edward Gillen, Louise D. Nielsen, and Gareth Smith

Subjects
Earth and Planetary Astrophysics (astro-ph.EP), Physics, 010308 nuclear & particles physics, Brown dwarf, FOS: Physical sciences, Astronomy, Astronomy and Astrophysics, Orbital eccentricity, Radius, 01 natural sciences, Exoplanet, Radial velocity, techniques: photometric, Photometry (astronomy), Stars, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, techniques: radial velocities, 0103 physical sciences, Spectral energy distribution, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), brown dwarfs, Astrophysics - Earth and Planetary Astrophysics
Abstract

We present the discovery of NGTS-19b, a high mass transiting brown dwarf discovered by the Next Generation Transit Survey (NGTS). We investigate the system using follow up photometry from the South African Astronomical Observatory, as well as sector 11 TESS data, in combination with radial velocity measurements from the CORALIE spectrograph to precisely characterise the system. We find that NGTS-19b is a brown dwarf companion to a K-star, with a mass of $69.5 ^{+5.7}_{-5.4}$ M$_{Jup}$ and radius of $1.034 ^{+0.055}_{-0.053}$ R$_{Jup}$. The system has a reasonably long period of 17.84 days, and a high degree of eccentricity of $0.3767 ^{+0.0061}_{-0.0061}$. The mass and radius of the brown dwarf imply an age of $0.46 ^{+0.26}_{-0.15}$ Gyr, however this is inconsistent with the age determined from the host star SED, suggesting that the brown dwarf may be inflated. This is unusual given that its large mass and relatively low levels of irradiation would make it much harder to inflate. NGTS-19b adds to the small, but growing number of brown dwarfs transiting main sequence stars, and is a valuable addition as we begin to populate the so called brown dwarf desert., Accepted for Publication in MNRAS

Published
2021
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3. A transit timing variation observed for the long-period extremely low-density exoplanet HIP 41378 f

Author

J. I. Vines, Chris Stockdale, Samantha Thompson, Michaël Gillon, Sarah L. Casewell, Richard G. West, C. Murray, Akihiko Fukui, Julien de Wit, Stéphane Udry, Rosanna H. Tilbrook, David J. Armstrong, Douglas R. Alves, L. Delrez, Benjamin V. Rackham, Edward M. Bryant, Valerio Nascimbeni, David R. Anderson, Samuel Gill, Matthew R. Burleigh, Enric Palle, Elsa Ducrot, Maximiliano Moyano, P. P. Pedersen, Monika Lendl, Peter J. Wheatley, Molly R. Kosiarek, Michael R. Goad, James S. Jenkins, Thiam-Guan Tan, Brice-Olivier Demory, Jack S. Acton, Amaury H. M. J. Triaud, Daniel Bayliss, Prajwal Niraula, Beth A. Henderson, Tianjun Gan, Norio Narita, Caroline Odden, Bronwen J. Hardee, Alexandre Santerne, Philipp Eigmüller, Maximilian N. Günther, A. Burdanov, D. Sebastian, Benjamin F. Cooke, Supachai Awiphan, Francisco J. Pozuelos, Hannu Parviainen, Emmanuel Jehin, 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), University of Warwick [Coventry], Institut d'Optique Graduate School (IOGS), Institut d'Astrophysique et de Géophysique [Liège], Université de Liège, National Astronomical Research Institute of Thailand (NARIT), Department of Physics and Astronomy [Leicester], University of Leicester, Cavendish Laboratory, University of Cambridge [UK] (CAM), Center for Space and Habitability (CSH), University of Bern, The University of Tokyo (UTokyo), Instituto de Astrofisica de Canarias (IAC), Space Sciences, Technologies and Astrophysics Research Institute (STAR), Universidad de Chile = University of Chile [Santiago] (UCHILE), Department of Astronomy and Astrophysics [UCSC Santa Cruz], University of California [Santa Cruz] (UC Santa Cruz), University of California (UC)-University of California (UC), Austrian Academy of Sciences (OeAW), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Observatoire Astronomique de l'Université de Genève (ObsGE), and Université de Genève = University of Geneva (UNIGE)

Subjects
Extrasolare Planeten und Atmosphären, planets and satellites: detection, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, Astrophysics, 01 natural sciences, techniques: photometric, Planet, Long period, 0103 physical sciences, Low density, Transit (astronomy), 10. No inequality, 010303 astronomy & astrophysics, Earth and Planetary Astrophysics (astro-ph.EP), Physics, planets and satellites: individual: HIP 41378 f, Transit-timing variation, 010308 nuclear & particles physics, 520 Astronomy, Astronomy and Astrophysics, Orbital period, Exoplanet, Photometry (astronomy), 13. Climate action, Space and Planetary Science, stars: individual: HIP 41378, Astrophysics - Earth and Planetary Astrophysics
Abstract

HIP 41378 f is a temperate $9.2\pm0.1 R_{\oplus}$ planet with period of 542.08 days and an extremely low density of $0.09\pm0.02$ g cm$^{-3}$. It transits the bright star HIP 41378 (V=8.93), making it an exciting target for atmospheric characterization including transmission spectroscopy. HIP 41378 was monitored photometrically between the dates of 2019 November 19 and November 28. We detected a transit of HIP 41378 f with NGTS, just the third transit ever detected for this planet, which confirms the orbital period. This is also the first ground-based detection of a transit of HIP 41378 f. Additional ground-based photometry was also obtained and used to constrain the time of the transit. The transit was measured to occur 1.50 hours earlier than predicted. We use an analytic transit timing variation (TTV) model to show the observed TTV can be explained by interactions between HIP 41378 e and HIP 41378 f. Using our TTV model, we predict the epochs of future transits of HIP 41378 f, with derived transit centres of T$_{C,4} = 2459355.087^{+0.031}_{-0.022}$ (May 2021) and T$_{C,5} = 2459897.078^{+0.114}_{-0.060}$ (Nov 2022)., Comment: Accepted for publication in MNRAS Letters. 6 pages, 2 figures

Published
2021
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4. Stellar flares detected with the Next Generation Transit Survey

Author

James A. G. Jackman, Jack S. Acton, Michael R. Goad, Rosanna H. Tilbrook, Didier Queloz, Edward Gillen, Sarah L. Casewell, Boris T. Gänsicke, Samuel Gill, Simon Hodgkin, Maximilian N. Günther, David R. Anderson, Richard G. West, Liam Raynard, Beth A. Henderson, Joshua T. Briegal, Chloe E. Pugh, Daniel Bayliss, Matthew R. Burleigh, James S. Jenkins, Peter J. Wheatley, Christopher A. Watson, Queloz, Didier [0000-0002-3012-0316], and Apollo - University of Cambridge Repository

Subjects
010504 meteorology & atmospheric sciences, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics, Stellar classification, 01 natural sciences, law.invention, stars: rotation, law, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Transit (astronomy), skin and connective tissue diseases, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Physics, Starspot, Astronomy and Astrophysics, Thin disc, starspots, Stars, Amplitude, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Physics::Space Physics, stars: flare, Astrophysics::Earth and Planetary Astrophysics, Data release, Astrophysics - Earth and Planetary Astrophysics, Flare
Abstract

We present the results of a search for stellar flares in the first data release from the Next Generation Transit Survey (NGTS). We have found 610 flares from 339 stars, with spectral types between F8 and M6, the majority of which belong to the Galactic thin disc. We have used the 13 second cadence NGTS lightcurves to measure flare properties such as the flare amplitude, duration and bolometric energy. We have measured the average flare occurrence rates of K and early to mid M stars and present a generalised method to measure these rates while accounting for changing detection sensitivities. We find that field age K and early M stars show similar flare behaviour, while fully convective M stars exhibit increased white-light flaring activity, which we attribute to their increased spin down time. We have also studied the average flare rates of pre-main sequence K and M stars, showing they exhibit increased flare activity relative to their main sequence counterparts., 21 pages, 13 figures, 5 tables. Accepted for publication in the Monthly Notices of the Royal Astronomical Society

Published
2021
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5. NGTS 15b, 16b, 17b, and 18b: four hot Jupiters from the Next-Generation Transit Survey

Author

Jessymol K. Thomas, Stéphane Udry, Alexander Chaushev, Matthew R. Burleigh, Louise D. Nielsen, Alexis M. S. Smith, Michael R. Goad, Richard G. West, James McCormac, Liam Raynard, James S. Jenkins, Sarah L. Casewell, Benjamin F. Cooke, Rosanna H. Tilbrook, François Bouchy, Ramotholo Sefako, Peter J. Wheatley, Beth A. Henderson, Joshua T. Briegal, Christopher A. Watson, Jose I. Vines, Daniel Bayliss, J. Costes, Jack S. Acton, Hannah L. Worters, Simon Hodgkin, Didier Queloz, H. Breytenbach, Samuel Gill, Maximiliano Moyano, Monika Lendl, Edward Gillen, David R. Anderson, Maximilian N. Günther, Philipp Eigmüller, Aleisha Hogan, David J. Armstrong, Douglas R. Alves, Edward M. Bryant, Queloz, Didier [0000-0002-3012-0316], and Apollo - University of Cambridge Repository

Subjects
Earth and Planetary Astrophysics (astro-ph.EP), Physics, Inflation (cosmology), planets and satellites: detection, 010308 nuclear & particles physics, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Radius, Planetary system, Parameter space, 01 natural sciences, planets and satellites: gaseous planets, Space and Planetary Science, Planet, 0103 physical sciences, Hot Jupiter, Transit (astronomy), 10. No inequality, planetary systems, 010303 astronomy & astrophysics, Main sequence, Astrophysics - Earth and Planetary Astrophysics
Abstract

We report the discovery of four new hot Jupiters with the Next Generation Transit Survey (NGTS). NGTS-15b, NGTS-16b, NGTS-17b, and NGTS-18b are short-period ($P, Accepted for publication in MNRAS

Published
2021
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6. NGTS clusters survey – II. White-light flares from the youngest stars in Orion

Author

Christopher A. Watson, Samuel Gill, Maximiliano Moyano, Claudia Belardi, Michael R. Goad, Sarah L. Casewell, Richard G. West, James McCormac, Liam Raynard, Peter J. Wheatley, David R. Anderson, Matthew R. Burleigh, Jack S. Acton, James S. Jenkins, Simon Hodgkin, Philipp Eigmüller, Rosanna H. Tilbrook, James A. G. Jackman, Edward Gillen, Andrew Grange, Didier Queloz, Apollo - University of Cambridge Repository, and Queloz, Didier [0000-0002-3012-0316]

Subjects
Extrasolare Planeten und Atmosphären, endocrine system, astro-ph.SR, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Library science, stars: pre-main-sequence, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Queen (playing card), stars: low-mass, 0103 physical sciences, White light, Astrophysics::Solar and Stellar Astrophysics, skin and connective tissue diseases, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, Earth and Planetary Astrophysics (astro-ph.EP), Physics, 010308 nuclear & particles physics, Astronomy and Astrophysics, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, astro-ph.EP, Physics::Space Physics, stars: flare, Administration (government), Astrophysics - Earth and Planetary Astrophysics
Abstract

We present the detection of high energy white-light flares from pre-main sequence stars associated with the Orion complex, observed as part of the Next Generation Transit Survey (NGTS). With energies up to $5.2\times10^{35}$ erg these flares are some of the most energetic white-light flare events seen to date. We have used the NGTS observations of flaring and non-flaring stars to measure the average flare occurrence rate for 4 Myr M0-M3 stars. We have also combined our results with those from previous studies to predict average rates for flares above $1\times10^{35}$ ergs for early M stars in nearby young associations., Comment: 10 pages, 5 figures, 5 tables. Accepted for publication in the Monthly Notices of the Royal Astronomical Society

Published
2020
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7. TOI-431/HIP 26013: a super-Earth and a sub-Neptune transiting a bright, early K dwarf, with a third RV planet

Author

Andrés Jordán, Sara Seager, Brett C. Addison, Maximilian N. Günther, Monika Lendl, Jack Okumura, Jorge Lillo-Box, Jon M. Jenkins, Roland Vanderspek, C. G. Tinney, Benjamin J. Fulton, Peter J. Wheatley, Erik A. Petigura, Beth A. Henderson, C. Stibbard, P. Figueira, Rafael Brahm, Eric L. N. Jensen, Michael Reefe, Cesar Briceno, Chris Stockdale, S. Hojjatpanah, Farisa Y. Morales, Alexis M. S. Smith, Caroline Dorn, Thomas Henning, Vardan Adibekyan, George W. King, Lauren M. Weiss, David R. Ciardi, Howard Isaacson, Richard P. Schwarz, Thomas Barclay, Stephen R. Kane, Keivan G. Stassun, David W. Latham, Malcolm Fridlund, Jack S. Acton, Ravit Helled, Sharon X. Wang, John Berberian, Joseph D. Twicken, J. F. Otegi, David R. Anderson, Sarah L. Casewell, Elise Furlan, Elisabeth Matthews, Johanna Teske, Rodrigo F. Díaz, Samuel Gill, Daniel Bayliss, Ian Crossfield, Peter Plavchan, Matthew W. Mengel, Joshua E. Schlieder, John F. Kielkopf, Stéphane Udry, E. Delgado Mena, H. P. Osborn, Avi Shporer, R. Cloutier, J. Villasenor, Duncan J. Wright, E. Gaidos, A. Osborn, K. I. Collins, Angelle Tanner, Nicholas M. Law, Björn Benneke, Joshua N. Winn, Fei Dai, Nicholas J. Scott, Erica J. Gonzales, Courtney D. Dressing, Sarah Ballard, Don Pollacco, Coel Hellier, Michael R. Goad, David J. Armstrong, Varoujan Gorjian, Paula Sarkis, Richard C. Kidwell, F. Zohrabi, Nuno C. Santos, David Barrado, Matthew R. Burleigh, Sergio Hoyer, Claire Geneser, Christopher J. Burke, Richard G. West, James McCormac, P. A. Strøm, Daniel Huber, Aleisha Hogan, Paul Robertson, Natalie M. Batalha, Edward M. Bryant, Liam Raynard, Karen A. Collins, Robert A. Wittenmyer, Mark E. Rose, Rachel A. Matson, Steve B. Howell, James S. Jenkins, Jose I. Vines, S. C. C. Barros, Néstor Espinoza, B. Cale, Andrew W. Howard, Diana Dragomir, Alexandre Santerne, M. Lund, Olivier Demangeon, Brendan P. Bowler, Benjamin F. Cooke, Xavier Dumusque, Andrew W. Mann, Hui Zhang, Carl Ziegler, Arpita Roy, Rosanna H. Tilbrook, Sérgio F. Sousa, George R. Ricker, Jonathan Horner, Elisa V. Quintana, Thiam-Guan Tan, Louise D. Nielsen, François Bouchy, University of New South Wales [Sydney] (UNSW), McDonald Observatory, University of Texas at Austin [Austin], Leiden Observatory [Leiden], Universiteit Leiden, Chalmers University of Technology [Gothenburg, Sweden], NASA Ames Research Center Cooperative for Research in Earth Science in Technology (ARC-CREST), NASA Ames Research Center (ARC), European Southern Observatory [Santiago] (ESO), European Southern Observatory (ESO), Instituto de Astrofísica e Ciências do Espaço (IASTRO), Center for Space Research [Cambridge] (CSR), Massachusetts Institute of Technology (MIT), Harvard-Smithsonian Center for Astrophysics (CfA), Harvard University-Smithsonian Institution, European Space Astronomy Centre (ESAC), Agence Spatiale Européenne = European Space Agency (ESA), 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), Département de Physique [Montréal], Université de Montréal (UdeM), 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), Department of Physics and Astronomy [Leicester], University of Leicester, Infrared Processing and Analysis Center (IPAC), California Institute of Technology (CALTECH), Optimisation - Système - Energie (GEPEA-OSE), Laboratoire de génie des procédés - environnement - agroalimentaire (GEPEA), Institut Universitaire de Technologie - Nantes (IUT Nantes), Université de Nantes (UN)-Université de Nantes (UN)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut Universitaire de Technologie Saint-Nazaire (IUT Saint-Nazaire), Université de Nantes (UN)-Ecole Polytechnique de l'Université de Nantes (EPUN), Université de Nantes (UN)-École nationale vétérinaire, agroalimentaire et de l'alimentation Nantes-Atlantique (ONIRIS)-Centre National de la Recherche Scientifique (CNRS)-Université Bretagne Loire (UBL)-IMT Atlantique (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Institut Universitaire de Technologie - La Roche-sur-Yon (IUT La Roche-sur-Yon), Université de Nantes (UN)-Institut Universitaire de Technologie - Nantes (IUT Nantes), Université de Nantes (UN), Institut für Virologie, Philipps University, MIT Kavli Institute for Astrophysics and Space Research, Max-Planck-Institut für Astronomie (MPIA), Max-Planck-Gesellschaft, Department of Geology and Geophysics [Mānoa], University of Hawai‘i [Mānoa] (UHM), Universität Zürich [Zürich] = University of Zurich (UZH), Department of Earth and Planetary Science [UC Berkeley] (EPS), University of California [Berkeley] (UC Berkeley), University of California (UC)-University of California (UC), Universidad de Chile = University of Chile [Santiago] (UCHILE), Pontificia Universidad Católica de Chile (UC), University of Louisville, Austrian Academy of Sciences (OeAW), Lund University [Lund], University of Warwick [Coventry], Observatoire Astronomique de l'Université de Genève (ObsGE), Université de Genève = University of Geneva (UNIGE), Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), German Aerospace Center (DLR), Swiss Bee Research Centre, Centre for Medical Image Computing (CMIC), and University College of London [London] (UCL)

Subjects
(TOI-431, planets and satellites: detection, Fundamental Parameters, 010504 meteorology & atmospheric sciences, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], (TOI-431, TIC 31374837), FOS: Physical sciences, Individual, Astrophysics, Q1, 01 natural sciences, Neptune, Planet, QB460, 0103 physical sciences, planets and satellites: fundamental parameters, 010303 astronomy & astrophysics, QB600, QC, 0105 earth and related environmental sciences, QB, Earth and Planetary Astrophysics (astro-ph.EP), Physics, Super-Earth, Astronomy and Astrophysics, Planets and Satellites, Radius, Light curve, Exoplanet, Radial velocity, Photometry (astronomy), Detection, 13. Climate action, Space and Planetary Science, planets and satellites: individual: (TOI-431, TIC 31374837), Astrophysics - Earth and Planetary Astrophysics
Abstract

We present the bright (V$_{mag} = 9.12$), multi-planet system TOI-431, characterised with photometry and radial velocities. We estimate the stellar rotation period to be $30.5 \pm 0.7$ days using archival photometry and radial velocities. TOI-431b is a super-Earth with a period of 0.49 days, a radius of 1.28 $\pm$ 0.04 R$_{\oplus}$, a mass of $3.07 \pm 0.35$ M$_{\oplus}$, and a density of $8.0 \pm 1.0$ g cm$^{-3}$; TOI-431d is a sub-Neptune with a period of 12.46 days, a radius of $3.29 \pm 0.09$ R$_{\oplus}$, a mass of $9.90^{+1.53}_{-1.49}$ M$_{\oplus}$, and a density of $1.36 \pm 0.25$ g cm$^{-3}$. We find a third planet, TOI-431c, in the HARPS radial velocity data, but it is not seen to transit in the TESS light curves. It has an $M \sin i$ of $2.83^{+0.41}_{-0.34}$ M$_{\oplus}$, and a period of 4.85 days. TOI-431d likely has an extended atmosphere and is one of the most well-suited TESS discoveries for atmospheric characterisation, while the super-Earth TOI-431b may be a stripped core. These planets straddle the radius gap, presenting an interesting case-study for atmospheric evolution, and TOI-431b is a prime TESS discovery for the study of rocky planet phase curves., Comment: 21 pages, 11 figures, 3 appendices, accepted for publication in MNRAS

Published
2021
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8. NGTS-14Ab: a Neptune-sized transiting planet in the desert

Author

Ph. Eigmüller, Edward M. Bryant, Rafael Brahm, Jack S. Acton, Samuel Gill, Aleisha Hogan, Maximiliano Moyano, Andrés Jordán, Monika Lendl, David R. Anderson, Alexander Chaushev, Sz. Csizmadia, Claudia Belardi, Benjamin F. Cooke, Maximilian N. Günther, Oliver Turner, Daniel Bayliss, Richard G. West, James McCormac, David J. Armstrong, Liam Raynard, Matthew R. Burleigh, Alexis M. S. Smith, Christopher A. Watson, Peter J. Wheatley, Anders Erikson, Jose I. Vines, Louise D. Nielsen, Juan Cabrera, François Bouchy, Rosanna H. Tilbrook, Heike Rauer, Edward Gillen, Michael R. Goad, Stéphane Udry, Beth A. Henderson, Joshua T. Briegal, and J. Costes

Subjects
Extrasolare Planeten und Atmosphären, planets and satellites: detection, planets and satellites: individual: NGTS-14Ab, 010504 meteorology & atmospheric sciences, Stellar mass, FOS: Physical sciences, Context (language use), 01 natural sciences, Neptune, Planet, 0103 physical sciences, Transit (astronomy), 010303 astronomy & astrophysics, planetary systems, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Physics, Leitungsbereich PF, Astronomy, Astronomy and Astrophysics, Planetary system, Exoplanet, Photometry (astronomy), binaries: general, 13. Climate action, Space and Planetary Science, astro-ph.EP, Astrophysics - Earth and Planetary Astrophysics
Abstract

Context: The sub-Jovian or Neptunian desert is a previously-identified region of parameter space where there is a relative dearth of intermediate-mass planets at short orbital periods. Aims: We present the discovery of a new transiting planetary system within the Neptunian desert, NGTS-14. Methods: Transits of NGTS-14Ab were discovered in photometry from the Next Generation Transit Survey (NGTS). Follow-up transit photometry was conducted from several ground-based facilities, as well as extracted from TESS full-frame images. We combine radial velocities from the HARPS spectrograph with the photometry in a global analysis to determine the system parameters. Results: NGTS-14Ab has a radius about 30 per cent larger than that of Neptune ($0.444\pm0.030~\mathrm{R_{Jup}}$), and is around 70 per cent more massive than Neptune ($0.092 \pm 0.012~\mathrm{M_{Jup}}$). It transits the main-sequence K1 star, NGTS-14A, with a period of 3.54 days, just far enough to have maintained at least some of its primordial atmosphere. We have also identified a possible long-period stellar mass companion to the system, NGTS-14B, and we investigate the binarity of exoplanet host stars inside and outside the Neptunian desert using Gaia., 11 pages, 7 figures. Accepted for publication in A&A

Published
2021
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9. The TESS-Keck Survey. II. An Ultra-short-period Rocky Planet and Its Siblings Transiting the Galactic Thick-disk Star TOI-561

Author

Phil Evans, Alexander Chaushev, Enric Palle, Karen A. Collins, Zachary R. Claytor, Ashley Chontos, Molly R. Kosiarek, John M. Brewer, Daniel Huber, Hannu Parviainen, Ian Crossfield, Thiam-Guan Tan, Felipe Murgas, Paul Robertson, Joseph M. Akana Murphy, George R. Ricker, J. Lubin, Richard P. Schwarz, Judah Van Zandt, Jessie L. Christiansen, Joshua E. Schlieder, Charles Beichman, Jack S. Acton, Lee J. Rosenthal, Rachel A. Matson, Stephen R. Kane, Mason G. MacDougall, S. Giacalone, Philipp Eigmüller, Corey Beard, Nicholas M. Law, Arpita Roy, Fei Dai, Erik A. Petigura, Edward M. Bryant, Norio Narita, Howard Isaacson, Teo Mocnik, Sara Seager, Cesar Briceno, Michael B. Lund, Keivan G. Stassun, Eric L. N. Jensen, Erica J. Gonzales, Michelle L. Hill, K. I. Collins, Elisabeth Matthews, Lauren M. Weiss, David R. Ciardi, Paul A. Dalba, Samuel Gill, Andrew W. Howard, Carl Ziegler, Andrew W. Mann, Courtney D. Dressing, Joseph D. Twicken, Steve B. Howell, Ryan A. Rubenzahl, Jon M. Jenkins, Benjamin J. Fulton, Natalie M. Batalha, Akihiko Fukui, Aida Behmard, and Joshua N. Winn

Subjects
010504 meteorology & atmospheric sciences, Exoplanet astronomy, Exoplanet evolution, Population, FOS: Physical sciences, Astrophysics, 01 natural sciences, Photometry (optics), Exoplanet formation, Planet, Observatory, 0103 physical sciences, Thick disk, Exoplanet detection methods, education, 010303 astronomy & astrophysics, Exoplanet systems, Solar and Stellar Astrophysics (astro-ph.SR), 0105 earth and related environmental sciences, Physics, Earth and Planetary Astrophysics (astro-ph.EP), education.field_of_study, Exoplanets, Astronomy and Astrophysics, Planetary system, Astrophysics - Astrophysics of Galaxies, Exoplanet, Exoplanet structure, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Terrestrial planet, Astrophysics - Earth and Planetary Astrophysics
Abstract

We report the discovery of TOI-561, a multi-planet system in the galactic thick disk that contains a rocky, ultra-short period planet (USP). This bright ($V=10.2$) star hosts three small transiting planets identified in photometry from the NASA TESS mission: TOI-561 b (TOI-561.02, P=0.44 days, $R_b = 1.45\pm0.11\,R_\oplus$), c (TOI-561.01, P=10.8 days, $R_c=2.90\pm0.13\,R_\oplus$), and d (TOI-561.03, P=16.3 days, $R_d=2.32\pm0.16\,R_\oplus$). The star is chemically ([Fe/H]$=-0.41\pm0.05$, [$\alpha$/H]$=+0.23\pm0.05$) and kinematically consistent with the galactic thick disk population, making TOI-561 one of the oldest ($10\pm3\,$Gyr) and most metal-poor planetary systems discovered yet. We dynamically confirm planets b and c with radial velocities from the W. M. Keck Observatory High Resolution Echelle Spectrometer. Planet b has a mass and density of $3.2\pm0.8\,M_\oplus$ and $5.5^{+2.0}_{-1.6}\,$g$\,$cm$^{-3}$, consistent with a rocky composition. Its lower-than-average density is consistent with an iron-poor composition, although an Earth-like iron-to-silicates ratio is not ruled out. Planet c is $7.0\pm2.3\,M_\oplus$ and $1.6\pm0.6\,$g$\,$cm$^{-3}$, consistent with an interior rocky core overlaid with a low-mass volatile envelope. Several attributes of the photometry for planet d (which we did not detect dynamically) complicate the analysis, but we vet the planet with high-contrast imaging, ground-based photometric follow-up and radial velocities. TOI-561 b is the first rocky world around a galactic thick-disk star confirmed with radial velocities and one of the best rocky planets for thermal emission studies., Comment: Accepted at The Astronomical Journal; 25 pages, 10 figures

Published
2021

10. Six transiting planets and a chain of Laplace resonances in TOI-178

Author

A. Leleu, Nathan Hara, Rosanna H. Tilbrook, Matthew J. Hooton, Jack S. Acton, Giuseppina Micela, Heike Rauer, Francisco J. Pozuelos, Xavier Dumusque, Michael R. Goad, T. Bárczy, Andrew Collier Cameron, Francesco Pepe, G. Lo Curto, Rafael Rebolo, Juan Cabrera, Pedro Figueira, M. Buder, Willy Benz, Romain Allart, Oliver Turner, Enric Palle, Alexis M. S. Smith, Ignasi Ribas, F. Ratti, M. Steller, Richard G. West, James McCormac, A. Lecavelier des Etangs, Alexandre C. M. Correia, Daniel Sebastian, S. G. Sousa, Emmanuel Jehin, Mathias Beck, J. Schneider, François Bouchy, Baptiste Lavie, J.-B. Delisle, Liam Raynard, Roberto Ragazzoni, K. Lam, H. Venus, Kate Gudrun Isaak, Roi Alonso, C. Murray, Laetitia Delrez, Martti H. Kristiansen, Mario Damasso, A. Bonfanti, David Ehrenreich, Stéphane Udry, Samuel Gill, Sergio Hoyer, Lionel Garcia, V. Adibekyan, Carina M. Persson, Maximiliano Moyano, Beth A. Henderson, Giampaolo Piotto, Andrés Jordán, Samantha Thompson, Alexis Brandeker, Elsa Ducrot, Daniel Angerhausen, Nuno C. Santos, David Barrado, Xavier Bonfils, Vincent Bourrier, F. Verrecchia, Monika Lendl, Andrea Mehner, C. Broeg, M. R. Zapatero Osorio, Matthew R. Burleigh, D. Futyan, Damien Ségransan, Amaury H. M. J. Triaud, Mahmoudreza Oshagh, C. Allende Prieto, J. Asquier, B. O. Demory, Philippe Robutel, C. Corral Van Damme, Nicola Rando, Malcolm Fridlund, Gisbert Peter, Roland Ottensamer, Alessandro Sozzetti, Paolo Molaro, James S. Jenkins, Melvyn B. Davies, Jorge Lillo-Box, S. Chamberlain, Thomas Beck, P. Di Marcantonio, Carlos Martins, Maximilian N. Günther, Daniel Bayliss, Jacques Laskar, Peter J. Wheatley, P. P. Pedersen, Nicolas Thomas, Nicholas A. Walton, Göran Olofsson, Marko Sestovic, David R. Anderson, Artem Burdanov, Kevin Heng, Manuel Guedel, Jose I. Vines, A. García Muñoz, Edward Gillen, Valérie Van Grootel, T. G. Wilson, Michaël Gillon, Olivier Demangeon, D. Wolter, Demetrio Magrin, G. Polenta, G. Anglada Escudé, Stefano Cristiani, J. Haldemann, László L. Kiss, H. P. Osborn, Valerio Nascimbeni, Aleisha Hogan, Ennio Poretti, Pierre F. L. Maxted, S. C. C. Barros, G. Boué, Sébastien Charnoz, Benjamin F. Cooke, Nicolas Billot, C. Reimers, Don Pollacco, Gaetano Scandariato, Luca Fossati, Douglas R. Alves, J. I. González Hernández, Edward M. Bryant, Anders Erikson, Nelson J. Nunes, Wolfgang Baumjohann, Yann Alibert, A. Suárez Mascareño, Antoine Simon, Gy. M. Szabó, C. Lovis, Magali Deleuil, Andrea Fortier, Isabella Pagano, A. Bekkelien, G. Di Persio, Didier Queloz, Davide Gandolfi, Centre Hospitalier Régional Universitaire [Lille] (CHRU Lille), 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 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), 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), 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), Observatoire Astronomique de l'Université de Genève (ObsGE), Université de Genève = University of Geneva (UNIGE), 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, ITA, USA, GBR, FRA, DEU, AUT, BEL, CHL, DNK, NLD, PRT, SWE, CHE, HUN, 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), 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), Université de Genève (UNIGE), 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), Swiss National Science Foundation, Agence Nationale de la Recherche (France), Science and Technology Facilities Council (UK), Belgian Science Policy Office, Université de Liège, Ministerio de Ciencia, Innovación y Universidades (España), European Commission, Generalitat de Catalunya, Fundação para a Ciência e a Tecnologia (Portugal), Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737, Alvarez, M. [0000-0002-6786-2620], Carrasco Martínez, J. M. [0000-0002-3029-5853], 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
Brightness, planets and satellites: detection, Laplace resonance, 010504 meteorology & atmospheric sciences, spectroscopic techniques, planets and satellites: dynamical evolution and stability, Astrophysics, 01 natural sciences, Transits, spectroscopic [Techniques], techniques: photometric, Planet, QB460, QB Astronomy, 010303 astronomy & astrophysics, planets and satellites dynamical evolution and stability, QC, Institut für Optische Sensorsysteme, QB, Physics, Earth and Planetary Astrophysics (astro-ph.EP), Laplace transform, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 520 Astronomy, photmetric [Techniques], 3rd-DAS, dynamical evolution and stability [Planets and satellites], planets and satellites detection, Astrophysics::Earth and Planetary Astrophysics, Extrasolare Planeten und Atmosphären, Techniques: photmetric, FOS: Physical sciences, Context (language use), SPECULOOS, Earth radius, Mean-motion resonance, 0103 physical sciences, Celestial mechanics, CHEOPS, QB600, 0105 earth and related environmental sciences, photometric techniques, TESS, Scattering, Leitungsbereich PF, photometric [Techniques], Astronomy and Astrophysics, celestial mechanics, 620 Engineering, detection [Planets and satellites], QC Physics, 13. Climate action, Space and Planetary Science, NGTS, Planetare Sensorsysteme, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Event (particle physics), techniques: spectroscopic, QB799, Planets and satellites: Detection, Planets and satellites: Dynamical evolution and stability, Techniques: Photometric, Techniques: Spectroscopic, Astrophysics - Earth and Planetary Astrophysics
Abstract

Leleu, A., et al., Determining the architecture of multi-planetary systems is one of the cornerstones of understanding planet formation and evolution. Resonant systems are especially important as the fragility of their orbital configuration ensures that no significant scattering or collisional event has taken place since the earliest formation phase when the parent protoplanetary disc was still present. In this context, TOI-178 has been the subject of particular attention since the first TESS observations hinted at the possible presence of a near 2:3:3 resonant chain. Here we report the results of observations from CHEOPS, ESPRESSO, NGTS, and SPECULOOS with the aim of deciphering the peculiar orbital architecture of the system. We show that TOI-178 harbours at least six planets in the super-Earth to mini-Neptune regimes, with radii ranging from 1.152to 2.87Earth radii and periods of 1.91, 3.24, 6.56, 9.96, 15.23, and 20.71 days. All planets but the innermost one form a 2:4:6:9:12 chain of Laplace resonances, and the planetary densities show important variations from planet to planet, jumping from 1.02to 0.177times the Earth's density between planets c and d. Using Bayesian interior structure retrieval models, we show that the amount of gas in the planets does not vary in a monotonous way, contrary to what one would expect from simple formation and evolution models and unlike other known systems in a chain of Laplace resonances. The brightness of TOI-178 (H = 8.76 mag, J = 9.37 mag, V = 11.95 mag) allows for a precise characterisation of its orbital architecture as well as of the physical nature of the six presently known transiting planets it harbours. The peculiar orbital configuration and the diversity in average density among the planets in the system will enable the study of interior planetary structures and atmospheric evolution, providing important clues on the formation of super-Earths and mini-Neptunes., The authors acknowledge support from the Swiss NCCR PlanetS and the Swiss National Science Foundation. Y.A. and M.J.H. acknowledge the support of the Swiss National Fund under grant 200020_172746. A.C.C. and T.W. acknowledge support from STFC consolidated grant number ST/M001296/1. 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. SH acknowledges CNES funding through the grant 837319. Based on data collected under the NGTS project at the ESO La Silla Paranal Observatory. The NGTS facility is operated by the consortium institutes with support from the UK Science and Technology Facilities Council (STFC) project ST/M001962/1. 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. V.A. acknowledges the support from FCT through Investigador FCT contract nr. IF/00650/2015/CP1273/CT0001. 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 “María 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. ABr was supported by the SNSA. A.C. acknowledges support by CFisUC projects (UIDB/04564/2020 and UIDP/04564/2020), GRAVITY (PTDC/FIS-AST/7002/2020), ENGAGE SKA (POCI-01-0145-FEDER-022217), and PHOBOS (POCI-01-0145-FEDER-029932), funded by COMPETE 2020 and FCT, Portugal. This work was supported by FCT - Fundaçãopara a Ciência e a Tecnologia through national funds and by FEDER through COMPETE2020 - Programa OperacionalCompetitividade e Internacionalização by these grants: UID/FIS/04434/2019; UIDB/04434/2020; UIDP/04434/2020; PTDC/FIS-AST/32113/2017 and POCI-01-0145-FEDER- 032113; PTDC/FIS-AST/28953/2017 and POCI-01-0145-FEDER-028953; PTDC/FIS-AST/28987/2017 and 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). M.F. and C.M.P. gratefully acknowledgethe 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 “Gaseousor rocky? Unveiling the nature of small worlds”. E.G. gratefully acknowledges support from the David and Claudia Harding Foundation in the form of a WintonExoplanet Fellowship. M.G. is an F.R.S.-FNRS Senior Research Associate. J.I.G.H. acknowledges financial support from Spanish Ministry of Science and Innovation (MICINN) under the 2013 Ramón y Cajal programme RYC-2013-14875. J.I.G.H., A.S.M., R.R., and C.A.P. acknowledge financial support from the Spanish MICINN AYA2017-86389-P. A.S.M. acknowledges financial support from the Spanish Ministry of Science and Innovation (MICINN) under the 2019 Juan de la Cierva Programme. MNG ackowledges support from the MIT Kavli Institute as a Juan Carlos Torres Fellow. J.H. acknowledges the support of the Swiss National Fund under grant 200020_172746. 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 forthe programme. J.S.J. acknowledges support by FONDECYT grant 1201371, and partial support from CONICYT project Basal AFB-170002. A.J. acknowledges support from ANID - Millennium Science Initiative - ICN12_009 and from FONDECYT project 1171208. P.M. acknowledges support from STFC research grant number ST/M001040/1. N.J.N is supported by the contract and exploratory project IF/00852/2015, and projects UID/FIS/04434/2019, PTDC/FIS-OUT/29048/2017, COMPETE2020: POCI-01-0145-FEDER-028987 & FCT: PTDC/FIS-AST/28987/2017. N.J.N is supported by the contract and exploratory project IF/00852/2015, and project PTDC/FIS-OUT/29048/2017. This work was also partially supported by a grant from the Simons Foundation (PI Queloz, grant number 327127). 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. S.G.S. acknowledges support from FCT through FCT contract nr. CEECIND/00826/2018 and POPH/FSE (EC). 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 project has been supported by the Hungarian National Research, Development and Innovation Office (NKFIH) grants GINOP-2.3.2-15-2016-00003, K-119517, K-125015, and the City of Szombathely under Agreement No. 67.177-21/2016. This research received funding from the MERAC foundation, from the European Research Council under the European Union’s Horizon 2020 research and innovation programme (grant agreement no 803193/ BEBOP, and from the Science and Technology Facilites Council (STFC, grant no ST/S00193X/1). V.V.G. is an F.R.S-FNRS Research Associate. J.I.V. acknowledges support of CONICYT-PFCHA/Doctorado Nacional-21191829. M. R. Z. O. acknowledges financial support from projects AYA2016-79425-C3-2-P and PID2019-109522GB-C51 from the Spanish Ministry of Science, Innovation and Universities.

Published
2021
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11. NGTS-13b: a hot 4.8 Jupiter-mass planet transiting a subgiant star

Author

Maximiliano Moyano, Andrés Jordán, Monika Lendl, Maximilian N. Günther, Peter J. Wheatley, Jack S. Acton, Beth A. Henderson, Sarah L. Casewell, Michael R. Goad, David R. Anderson, Alexander Chaushev, Samuel Gill, Richard G. West, James McCormac, Liam Raynard, Nolan Grieves, Didier Queloz, Julia V. Seidel, Jose I. Vines, Stéphane Udry, Louise D. Nielsen, François Bouchy, Rosanna H. Tilbrook, Benjamin F. Cooke, Daniel Bayliss, Matthew R. Burleigh, Damien Ségransan, P. Eigmueller, James S. Jenkins, Douglas R. Alves, Edward M. Bryant, Alexis M. S. Smith, Edward Gillen, Aleisha Hogan, Queloz, Didier [0000-0002-3012-0316], and Apollo - University of Cambridge Repository

Subjects
Physics, Earth and Planetary Astrophysics (astro-ph.EP), planets and satellites: detection, 010504 meteorology & atmospheric sciences, planets and satellites: individual: NGTS-13b, Subgiant, Metallicity, Brown dwarf, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Accretion (astrophysics), Exoplanet, techniques: photometric, 13. Climate action, Space and Planetary Science, Planet, 0103 physical sciences, Hot Jupiter, techniques: radial velocities, 010303 astronomy & astrophysics, Jupiter mass, 0105 earth and related environmental sciences, Astrophysics - Earth and Planetary Astrophysics
Abstract

We report the discovery of the massive hot Jupiter NGTS-13b by the Next Generation Transit Survey (NGTS). The V = 12.7 host star is likely in the subgiant evolutionary phase with log g$_{*}$ = 4.04 $\pm$ 0.05, T$_{eff}$ = 5819 $\pm$ 73 K, M$_{*}$ = 1.30$^{+0.11}_{-0.18}$ M$_{\odot}$, and R$_{*}$ = 1.79 $\pm$ 0.06 R$_{\odot}$. NGTS detected a transiting planet with a period of P = 4.12 days around the star, which was later validated with the Transiting Exoplanet Survey Satellite (TESS; TIC 454069765). We confirm the planet using radial velocities from the CORALIE spectrograph. Using NGTS and TESS full-frame image photometry combined with CORALIE radial velocities we determine NGTS-13b to have a radius of R$_{P}$ = 1.142 $\pm$ 0.046 R$_{Jup}$, mass of M$_{P}$ = 4.84 $\pm$ 0.44 M$_{Jup}$ and eccentricity e = 0.086 $\pm$ 0.034. Some previous studies suggest that $\sim$4 M$_{Jup}$ may be a border between two separate formation scenarios (e.g., core accretion and disk instability) and that massive giant planets share similar formation mechanisms as lower-mass brown dwarfs. NGTS-13b is just above 4 M$_{Jup}$ making it an important addition to the statistical sample needed to understand the differences between various classes of substellar companions. The high metallicity, [Fe/H] = 0.25 $\pm$ 0.17, of NGTS-13 does not support previous suggestions that massive giants are found preferentially around lower metallicity host stars, but NGTS-13b does support findings that more massive and evolved hosts may have a higher occurrence of close-in massive planets than lower-mass unevolved stars., 11 pages, 9 figures, 4 tables, accepted by Astronomy & Astrophysics

Published
2021
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12. An eclipsing M-dwarf close to the hydrogen burning limit from NGTS

Author

Peter J. Wheatley, Maximiliano Moyano, Maximilian N. Günther, Jack S. Acton, Stéphane Udry, Philipp Eigmüller, Matthew R. Burleigh, Christopher A. Watson, James S. Jenkins, Richard G. West, James McCormac, Jose I. Vines, Samuel Gill, Liam Raynard, Rosanna H. Tilbrook, Boris T. Gänsicke, Michael R. Goad, François Bouchy, Sarah L. Casewell, Louise D. Nielsen, Daniel Bayliss, Edward Gillen, and Edward M. Bryant

Subjects
Physics, Extrasolare Planeten und Atmosphären, Earth and Planetary Astrophysics (astro-ph.EP), astro-ph.SR, 010308 nuclear & particles physics, Library science, binaries: eclipsing, FOS: Physical sciences, Astronomy and Astrophysics, 01 natural sciences, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, Observatory, stars: low-mass, 0103 physical sciences, astro-ph.EP, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract

We present the discovery of NGTS J0930-18, an extreme mass ratio eclipsing M-dwarf binary system with an early M-dwarf primary and a late M-dwarf secondary close to the hydrogen burning limit. Global modelling of photometry and radial velocities reveals that the secondary component (NGTS J0930-18 B) has a mass of M=$0.0818 ^{+0.0040}_{-0.0015}$ $M_*$ and radius of R=$0.1059 ^{+0.0023}_{-0.0021}$ $R_*$, making it one of the lowest mass stars with direct mass and radius measurements. With a mass ratio of q =$0.1407 ^{+0.0065}_{-0.017}$, NGTS J0930-18 has the lowest mass ratio of any known eclipsing M-dwarf binary system, posing interesting questions for binary star formation and evolution models. The mass and radius of NGTS J0930-18 B is broadly consistent with stellar evolutionary models. NGTS J0930-18 B lies in the sparsely populated mass radius parameter space close to the substellar boundary. Precise measurements of masses and radii from single lined eclipsing binary systems of this type are vital for constraining the uncertainty in the mass-radius relationship - of importance due to the growing number of terrestrial planets being discovered around low mass stars., Comment: Accepted for Publication in MNRAS

Published
2020
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13. NGTS-12b: A sub-Saturn mass transiting exoplanet in a 7.53 day orbit

Author

Benjamin F. Cooke, Jack S. Acton, Christopher A. Watson, Jose I. Vines, Maximilian N. Günther, Daniel Bayliss, Michael R. Goad, Samuel Gill, Richard G. West, James McCormac, David R. Anderson, Maximiliano Moyano, Sarah L. Casewell, Anders Erikson, Liam Raynard, Philipp Eigmüller, Monika Lendl, Juan Cabrera, Peter J. Wheatley, David J. Armstrong, Louise D. Nielsen, Aleisha Hogan, Heike Rauer, Dimitri Veras, Didier Queloz, François Bouchy, Edward Gillen, Szilard Csizmadia, Alexis M. S. Smith, Edward M. Bryant, Rosanna H. Tilbrook, Nolan Grieves, Beth A. Henderson, Joshua T. Briegal, Stéphane Udry, Alexander Chaushev, Matthew R. Burleigh, James S. Jenkins, Queloz, Didier [0000-0002-3012-0316], and Apollo - University of Cambridge Repository

Subjects
Extrasolare Planeten und Atmosphären, planets and satellites: detection, Library science, FOS: Physical sciences, Q1, 01 natural sciences, techniques: photometric, Observatory, 0103 physical sciences, QB460, media_common.cataloged_instance, stars: individual: NGTS-12, European union, QA, 010303 astronomy & astrophysics, planetary systems, QB600, QC, media_common, QB, Physics, Earth and Planetary Astrophysics (astro-ph.EP), 010308 nuclear & particles physics, European research, Leitungsbereich PF, Astronomy and Astrophysics, Exoplanet, Space and Planetary Science, Astrophysics - Earth and Planetary Astrophysics
Abstract

We report the discovery of the transiting exoplanet NGTS-12b by the Next Generation Transit Survey (NGTS). The host star, NGTS-12, is a V=12.38 mag star with an effective temperature of T$_{\rm eff}$=$5690\pm130$ K. NGTS-12b orbits with a period of $P=7.53$d, making it the longest period planet discovered to date by the main NGTS survey. We verify the NGTS transit signal with data extracted from the TESS full-frame images, and combining the photometry with radial velocity measurements from HARPS and FEROS we determine NGTS-12b to have a mass of $0.208\pm0.022$ M$_{J}$ and a radius of $1.048\pm0.032$ R$_{J}$. NGTS-12b sits on the edge of the Neptunian desert when we take the stellar properties into account, highlighting the importance of considering both the planet and star when studying the desert. The long period of NGTS-12b combined with its low density of just $0.223\pm0.029$ g cm$^{-3}$ make it an attractive target for atmospheric characterization through transmission spectroscopy with a Transmission Spectroscopy Metric of 89.4., Comment: Accepted for publication in MNRAS, 11 pages

Published
2020

14. A long period (P = 61.8-d) M5V dwarf eclipsing a Sun-like star from TESS and NGTS

Author

Michael R. Goad, Jack S. Acton, Maximilian N. Günther, Samuel Gill, Maximiliano Moyano, Monika Lendl, Fracois Bouchy, Stéphane Udry, Claudia Belardi, Daniel Bayliss, Peter J. Wheatley, Alexander Chaushev, Sarah L. Casewell, Matthew R. Burleigh, David R. Anderson, Rossana H. Tilbrook, Oliver Turner, Christopher A. Watson, Richard G. West, James McCormac, Alexis M. S. Smith, James A. G. Jackman, Don Pollacco, James S. Jenkins, Edward M. Bryant, Louise D. Nielsen, Liam Raynard, Jose I. Vines, H. P. Osborn, and Benjamin F. Cooke

Subjects
Physics, Extrasolare Planeten und Atmosphären, Earth and Planetary Astrophysics (astro-ph.EP), 010308 nuclear & particles physics, binaries: eclipsing, FOS: Physical sciences, Astronomy and Astrophysics, 01 natural sciences, Astrophysics - Solar and Stellar Astrophysics, eclipsing [binaries], Space and Planetary Science, Long period, 0103 physical sciences, 010303 astronomy & astrophysics, Humanities, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics - Earth and Planetary Astrophysics
Abstract

The Transiting Exoplanet Survey Satellite (TESS) has produced a large number of single transit event candidates which are being monitored by the Next Generation Transit Survey (NGTS). We observed a second epoch for the TIC-231005575 system (Tmag = 12.06, Teff = 5500 +- 85 K) with NGTS and a third epoch with Las Cumbres Observatory's (LCO) telescope in South Africa to constrain the orbital period (P = 61.777 d). Subsequent radial velocity measurements with CORALIE revealed the transiting object has a mass of M2 = 0.128 +- 0.003 M$_\odot$, indicating the system is a G-M binary. The radius of the secondary is R2 = 0.154 +- 0.008 R$_\odot$ and is consistent with models of stellar evolution to better than 1-$\sigma$., Comment: 8 pages, 5 figures, 3 tables. Accepted for publication in MNRAS

Published
2020
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15. Three short-period Jupiters from TESS: HIP 65Ab, TOI-157b, and TOI-169b

Author

Z. Csubry, C. Lovis, Matthew R. Burleigh, Damien Ségransan, George R. Ricker, L. A. dos Santos, Norio Narita, Jack S. Acton, Oliver Turner, Logan Pearce, Motohide Tamura, James McCormac, James S. Jenkins, K. I. Collins, Sara Seager, Paula Sarkis, Liam Raynard, K. A. Collins, Th. Henning, F. Pozuelos, David W. Latham, Diana Kossakowski, Avi Shporer, Roland Vanderspek, Tianjun Gan, Trifon Trifonov, Jon M. Jenkins, Mayuko Mori, Andrew Vanderburg, Khalid Barkaoui, Michaël Gillon, Néstor Espinoza, M. Stalport, Chelsea X. Huang, François Bouchy, Stéphane Udry, Baptiste Lavie, David R. Ciardi, Rhodes Hart, Maximiliano Moyano, Emmanuel Jehin, Andrés Jordán, Rosanna H. Tilbrook, G. Wingham, David J. Osip, Cesar Briceno, Monika Lendl, Michael Fausnaugh, Gáspár Á. Bakos, Benjamin F. Cooke, Saul Rappaport, Julia V. Seidel, Christopher Stockdale, Vincent Suc, Eric B. Ting, Natalia Guerrero, J. P. de Leon, John F. Kielkopf, Janis Hagelberg, Howard M. Relles, Zhuchang Zhan, Nicholas M. Law, Rafael Brahm, Joshua N. Winn, Thiam-Guan Tan, Waqas Bhatti, Peter J. Wheatley, Louise D. Nielsen, Ph. Eigmüller, Edward M. Bryant, C. Ziegler, Francesco Pepe, Andrew W. Mann, Maxime Marmier, Thomas Barclay, M. R. Goad, and J. F. Otegi

Subjects
Extrasolare Planeten und Atmosphären, Physics, planets and satellites: detection, planets and satellites: individual: TOI-129, media_common.quotation_subject, planets and satellites: individual: HIP 65A, planets and satellites: individual: TOI-157, Astronomy and Astrophysics, Astrophysics, Orbital period, 01 natural sciences, Exoplanet, Stars, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Neptune, Sky, Planet, 0103 physical sciences, Hot Jupiter, Roche lobe, 010306 general physics, 010303 astronomy & astrophysics, Astrophysics - Earth and Planetary Astrophysics, media_common
Abstract

We report the confirmation and mass determination of three hot Jupiters discovered by the Transiting Exoplanet Survey Satellite (TESS) mission: HIP 65Ab (TOI-129, TIC-201248411) is an ultra-short-period Jupiter orbiting a bright (V = 11.1 mag) K4-dwarf every 0.98 days. It is a massive 3.213 ± 0.078 MJ planet in a grazing transit configuration with an impact parameter of b = 1.17−0.08+0.10. As a result the radius is poorly constrained, 2.03−0.49+0.61RJ. The planet’s distance to its host star is less than twice the separation at which it would be destroyed by Roche lobe overflow. It is expected to spiral into HIP 65A on a timescale ranging from 80 Myr to a few gigayears, assuming a reduced tidal dissipation quality factor of Qs′ = 107 − 109. We performed a full phase-curve analysis of the TESS data and detected both illumination- and ellipsoidal variations as well as Doppler boosting. HIP 65A is part of a binary stellar system, with HIP 65B separated by 269 AU (3.95 arcsec on sky). TOI-157b (TIC 140691463) is a typical hot Jupiter with a mass of 1.18 ± 0.13 MJ and a radius of 1.29 ± 0.02 RJ. It has a period of 2.08 days, which corresponds to a separation of just 0.03 AU. This makes TOI-157 an interesting system, as the host star is an evolved G9 sub-giant star (V = 12.7). TOI-169b (TIC 183120439) is a bloated Jupiter orbiting a V = 12.4 G-type star. It has a mass of 0.79 ±0.06 MJ and a radius of 1.09−0.05+0.08RJ. Despite having the longest orbital period (P = 2.26 days) of the three planets, TOI-169b receives the most irradiation and is situated on the edge of the Neptune desert. All three host stars are metal rich with [Fe / H] ranging from 0.18 to0.24.

Published
2020
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16. An Ultra-Hot Neptune in the Neptune desert

Author

Todd C. Klaus, Jose I. Vines, Ruth Titz-Weider, Motohide Tamura, Jessie L. Christiansen, Samuel N. Quinn, M. G. Soto, J. Villasenor, Pablo Rojas, George R. Ricker, Simon R. Walker, Maximiliano Moyano, Nicolás T. Kurtovic, Sara Seager, Sean McCauliff, Maximilian N. Günther, Andrés Jordán, Juan Cabrera, Pascal Torres, Michael R. Goad, Jerome de Leon, Giovanni Isopi, David R. Ciardi, Daniel Bayliss, K. I. Collins, Peter J. Wheatley, Jack J. Lissauer, Norio Narita, David W. Latham, François Bouchy, Sarah L. Casewell, Oliver Turner, Mayuko Mori, Andrea Ercolino, Cristobal Petrovich, Richard G. West, E. Foxell, Claudia Belardi, Philipp Eigmüller, James McCormac, Tom Louden, Eric D. Lopez, Liam Raynard, Benjamin F. Cooke, Edward Gillen, George W. King, Allyson Bieryla, Karen A. Collins, Matias Diaz, Heike Rauer, David J. Armstrong, Jack S. Acton, James A. G. Jackman, Don Pollacco, Anders Erikson, Néstor Espinoza, Michael Vezie, Samuel Gill, Nicholas M. Law, Carl Ziegler, Jon M. Jenkins, Edward M. Bryant, Rafael Brahm, Alexis M. S. Smith, Charles Beichman, Boris T. Gänsicke, Roland Vanderspek, Andrew W. Mann, Taku Nishiumi, Pía Cortés-Zuleta, Didier Queloz, Rosanna H. Tilbrook, Matthew J. Hooton, Louise D. Nielsen, Joshua N. Winn, Christopher J. Burke, Alexander Chaushev, Matthew R. Burleigh, Enric Palle, James S. Jenkins, Christopher E. Henze, Stéphane Udry, F. Mallia, Christopher A. Watson, Jenkins, JS [0000-0003-2733-8725], Espinoza, N [0000-0001-9513-1449], Brahm, R [0000-0002-9158-7315], Cortés-Zuleta, P [0000-0002-6174-4666], Wheatley, PJ [0000-0003-1452-2240], Winn, JN [0000-0002-4265-047X], Seager, S [0000-0002-6892-6948], Jenkins, JM [0000-0002-4715-9460], Bieryla, A [0000-0001-6637-5401], Christiansen, JL [0000-0002-8035-4778], Mori, M [0000-0003-1368-6593], Narita, N [0000-0001-8511-2981], Nishiumi, T [0000-0003-1510-8981], Tamura, M [0000-0002-6510-0681], Lissauer, JJ [0000-0001-6513-1659], Collins, KA [0000-0001-6588-9574], Collins, KI [0000-0003-2781-3207], Armstrong, DJ [0000-0002-5080-4117], Bayliss, D [0000-0001-6023-1335], Cabrera, J [0000-0001-6653-5487], Casewell, SL [0000-0003-2478-0120], Eigmüller, P [0000-0003-4096-0594], Günther, MN [0000-0002-3164-9086], Hooton, MJ [0000-0003-0030-332X], Queloz, D [0000-0002-3012-0316], Smith, AMS [0000-0002-2386-4341], Udry, S [0000-0001-7576-6236], Watson, CA [0000-0002-9718-3266], West, RG [0000-0001-6604-5533], and Apollo - University of Cambridge Repository

Subjects
Extrasolare Planeten und Atmosphären, Earth and Planetary Astrophysics (astro-ph.EP), astro-ph.SR, 010504 meteorology & atmospheric sciences, Leitungsbereich PF, Library science, FOS: Physical sciences, Astronomy and Astrophysics, Northern ireland, 01 natural sciences, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Political science, 0103 physical sciences, astro-ph.EP, Astrophysics::Solar and Stellar Astrophysics, Christian ministry, Astrophysics::Earth and Planetary Astrophysics, 010303 astronomy & astrophysics, Research center, Solar and Stellar Astrophysics (astro-ph.SR), 0105 earth and related environmental sciences, QB, Astrophysics - Earth and Planetary Astrophysics
Abstract

About one out of 200 Sun-like stars has a planet with an orbital period shorter than one day: an ultra-short-period planet (Sanchis-ojeda et al. 2014; Winn et al. 2018). All of the previously known ultra-short-period planets are either hot Jupiters, with sizes above 10 Earth radii (Re), or apparently rocky planets smaller than 2 Re. Such lack of planets of intermediate size (the "hot Neptune desert") has been interpreted as the inability of low-mass planets to retain any hydrogen/helium (H/He) envelope in the face of strong stellar irradiation. Here, we report the discovery of an ultra-short-period planet with a radius of 4.6 Re and a mass of 29 Me, firmly in the hot Neptune desert. Data from the Transiting Exoplanet Survey Satellite (Ricker et al. 2015) revealed transits of the bright Sun-like star \starname\, every 0.79 days. The planet's mean density is similar to that of Neptune, and according to thermal evolution models, it has a H/He-rich envelope constituting 9.0^(+2.7)_(-2.9)% of the total mass. With an equilibrium temperature around 2000 K, it is unclear how this "ultra-hot Neptune" managed to retain such an envelope. Follow-up observations of the planet's atmosphere to better understand its origin and physical nature will be facilitated by the star's brightness (Vmag=9.8)., Comment: 26 pages, 10 figures, 3 tables. Published in Nature Astronomy (21/09/2020)

Published
2020
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17. NGTS J214358.5−380102 – NGTS discovery of the most eccentric known eclipsing M-dwarf binary system

Author

Philipp Eigmüller, Benjamin F. Cooke, Matthew R. Burleigh, James S. Jenkins, Stéphane Udry, Sarah L. Casewell, Michael R. Goad, David R. Anderson, Richard G. West, James McCormac, Samuel Gill, Maximiliano Moyano, Liam Raynard, Monika Lendl, Louise D. Nielsen, Daniel Bayliss, Richard Alexander, Claudia Belardi, Rossanna H. Tilbrook, Tom Louden, Peter J. Wheatley, Jack S. Acton, James A. G. Jackman, Edward M. Bryant, Christopher A. Watson, and Jose I. Vines

Subjects
Physics, Extrasolare Planeten und Atmosphären, Earth and Planetary Astrophysics (astro-ph.EP), 010308 nuclear & particles physics, European research, Library science, binaries: eclipsing, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, eclipsing [binaries], Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, 010303 astronomy & astrophysics, Administration (government), Astrophysics::Galaxy Astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics - Earth and Planetary Astrophysics
Abstract

We present the discovery of NGTS J214358.5-380102, an eccentric M-dwarf binary discovered by the Next Generation Transit Survey. The system period of 7.618 days is greater than many known eclipsing M-dwarf binary systems. Its orbital eccentricity of $0.323^{+0.0014}_{-0.0037}$, is large relative to the period and semi-major axis of the binary. Global modelling of photometry and radial velocities indicate stellar masses of $M_A$=$0.426 ^{+0.0056}_{-0.0049}$, $M_B$=$0.455 ^{+0.0058}_{-0.0052}$ and stellar radii $R_A$=$0.461 ^{+0.038}_{-0.025}$ $R_B$=$0.411 ^{+0.027}_{-0.039}$, respectively. Comparisons with stellar models for low mass stars show that one star is consistent with model predictions whereas the other is substantially oversized. Spectral analysis of the system suggests a primary of spectral type M3V, consistent with both modelled masses and radii, and with SED fitting of NGTS photometry. As the most eccentric eclipsing M-dwarf binary known, NGTS J214358.5-380102 provides an interesting insight into the strength of tidal effects in the circularisation of stellar orbits., Comment: Accepted for Publication in MNRAS

Published
2020
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18. A remnant planetary core in the hot-Neptune desert

Author

David J. Armstrong, Théo A. Lopez, Vardan Adibekyan, Richard A. Booth, Edward M. Bryant, Karen A. Collins, Magali Deleuil, Alexandre Emsenhuber, Chelsea X. Huang, George W. King, Jorge Lillo-Box, Jack J. Lissauer, Elisabeth Matthews, Olivier Mousis, Louise D. Nielsen, Hugh Osborn, Jon Otegi, Nuno C. Santos, Sérgio G. Sousa, Keivan G. Stassun, Dimitri Veras, Carl Ziegler, Jack S. Acton, Jose M. Almenara, David R. Anderson, David Barrado, Susana C. C. Barros, Daniel Bayliss, Claudia Belardi, Francois Bouchy, César Briceño, Matteo Brogi, David J. A. Brown, Matthew R. Burleigh, Sarah L. Casewell, Alexander Chaushev, David R. Ciardi, Kevin I. Collins, Knicole D. Colón, Benjamin F. Cooke, Ian J. M. Crossfield, Rodrigo F. Díaz, Elisa Delgado Mena, Olivier D. S. Demangeon, Caroline Dorn, Xavier Dumusque, Philipp Eigmüller, Michael Fausnaugh, Pedro Figueira, Tianjun Gan, Siddharth Gandhi, Samuel Gill, Erica J. Gonzales, Michael R. Goad, Maximilian N. Günther, Ravit Helled, Saeed Hojjatpanah, Steve B. Howell, James Jackman, James S. Jenkins, Jon M. Jenkins, Eric L. N. Jensen, Grant M. Kennedy, David W. Latham, Nicholas Law, Monika Lendl, Michael Lozovsky, Andrew W. Mann, Maximiliano Moyano, James McCormac, Farzana Meru, Christoph Mordasini, Ares Osborn, Don Pollacco, Didier Queloz, Liam Raynard, George R. Ricker, Pamela Rowden, Alexandre Santerne, Joshua E. Schlieder, Sara Seager, Lizhou Sha, Thiam-Guan Tan, Rosanna H. Tilbrook, Eric Ting, Stéphane Udry, Roland Vanderspek, Christopher A. Watson, Richard G. West, Paul A. Wilson, Joshua N. Winn, Peter Wheatley, Jesus Noel Villasenor, Jose I. Vines, Zhuchang Zhan, 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, Armstrong, David J [0000-0002-5080-4117], Collins, Karen A [0000-0001-6588-9574], Emsenhuber, Alexandre [0000-0002-8811-1914], Lillo-Box, Jorge [0000-0003-3742-1987], Lissauer, Jack J [0000-0001-6513-1659], Santos, Nuno C [0000-0003-4422-2919], Stassun, Keivan G [0000-0002-3481-9052], Veras, Dimitri [0000-0001-8014-6162], Barrado, David [0000-0002-5971-9242], Collins, Kevin I [0000-0003-2781-3207], Demangeon, Olivier DS [0000-0001-7918-0355], Dumusque, Xavier [0000-0002-9332-2011], Eigmüller, Philipp [0000-0003-4096-0594], Jenkins, Jon M [0000-0002-4715-9460], Jensen, Eric LN [0000-0002-4625-7333], Kennedy, Grant M [0000-0001-6831-7547], Mordasini, Christoph [0000-0002-1013-2811], Santerne, Alexandre [0000-0002-3586-1316], Seager, Sara [0000-0002-6892-6948], Sha, Lizhou [0000-0001-5401-8079], Udry, Stéphane [0000-0001-7576-6236], West, Richard G [0000-0001-6604-5533], Wilson, Paul A [0000-0002-7823-1090], Winn, Joshua N [0000-0002-4265-047X], Wheatley, Peter [0000-0003-1452-2240], Apollo - University of Cambridge Repository, Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737, Collins, K. A. [0000-0002-4317-142X], Lillo Box, J. [0000-0003-3742-1987], Matthews, E. [0000-0003-0593-1560], Sousa, S. [0000-0002-3631-6440], National Aeronautics and Space Administration (NASA), Fundação para a Ciência e a Tecnologia (FCT), Agencia Estatal de Investigación (AEI), Science and Technology Facilities Council (STFC), Fondo Nacional de Desarrollo Científico y Tecnológico (FONDECYT), Unidad de Excelencia María de Maeztu del Instituto Nacional de Técnica Aeroespacial y CSIC, and French Programme National de Planetologie

Subjects
Extrasolare Planeten und Atmosphären, astro-ph.SR, 010504 meteorology & atmospheric sciences, Gas giant, 530 Physics, FOS: Physical sciences, TOI-849b, 01 natural sciences, Astrobiology, Planet, 0103 physical sciences, Planetary Core, Astrophysics::Solar and Stellar Astrophysics, Hot Neptune, Desert, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, QB, Earth and Planetary Astrophysics (astro-ph.EP), Physics, Multidisciplinary, Planetary core, 520 Astronomy, Giant planet, 620 Engineering, Accretion (astrophysics), Exoplanet, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, [SDU]Sciences of the Universe [physics], astro-ph.EP, Neptune, Astrophysics::Earth and Planetary Astrophysics, Planetary mass, Astrophysics - Earth and Planetary Astrophysics
Abstract

The interiors of giant planets remain poorly understood. Even for the planets in the Solar System, difficulties in observation lead to large uncertainties in the properties of planetary cores. Exoplanets that have undergone rare evolutionary processes provide a route to understanding planetary interiors. Planets found in and near the typically barren hot-Neptune 'desert' (a region in mass-radius space that contains few planets) have proved to be particularly valuable in this regard. These planets include HD149026b, which is thought to have an unusually massive core, and recent discoveries such as LTT9779b and NGTS-4b, on which photoevaporation has removed a substantial part of their outer atmospheres. Here we report observations of the planet TOI-849b, which has a radius smaller than Neptune's but an anomalously large mass of $39.1^{+2.7}_{-2.6}$ Earth masses and a density of $5.2^{+0.7}_{-0.8}$ grams per cubic centimetre, similar to Earth's. Interior structure models suggest that any gaseous envelope of pure hydrogen and helium consists of no more than $3.9^{+0.8}_{-0.9}$ per cent of the total planetary mass. The planet could have been a gas giant before undergoing extreme mass loss via thermal self-disruption or giant planet collisions, or it could have avoided substantial gas accretion, perhaps through gap opening or late formation. Although photoevaporation rates cannot account for the mass loss required to reduce a Jupiter-like gas giant, they can remove a small (a few Earth masses) hydrogen and helium envelope on timescales of several billion years, implying that any remaining atmosphere on TOI-849b is likely to be enriched by water or other volatiles from the planetary interior. We conclude that TOI-849b is the remnant core of a giant planet., Published in Nature. This is a preprint of the article, before minor changes made during the refereeing and editing process. The published PDF is at https://www.nature.com/articles/s41586-020-2421-7 and can be accessed for free by following this link: https://rdcu.be/b5miB . Abstract updated to match published version

Published
2020
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19. NGTS and WASP photometric recovery of a single-transit candidate from TESS

Author

Andrew Collier Cameron, Alexis M. S. Smith, Louise D. Nielsen, Maximiliano Moyano, Monika Lendl, Claudia Belardi, Oliver Turner, Rosanna H. Tilbrook, Richard G. West, James McCormac, Stéphane Udry, Liam Raynard, Michael R. Goad, Alexander Chaushev, Samuel Gill, Matthew R. Burleigh, James S. Jenkins, Maximilian N. Günther, Sarah L. Casewell, François Bouchy, David R. Anderson, Peter J. Wheatley, Jack S. Acton, Benjamin F. Cooke, Daniel Bayliss, Coel Hellier, James A. G. Jackman, Don Pollacco, Edward M. Bryant, 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
Extrasolare Planeten und Atmosphären, FOS: Physical sciences, Library science, Q1, 01 natural sciences, QB460, 0103 physical sciences, QB Astronomy, 010303 astronomy & astrophysics, QC, QB600, Solar and Stellar Astrophysics (astro-ph.SR), QB, Earth and Planetary Astrophysics (astro-ph.EP), Physics, 010308 nuclear & particles physics, eclipsing [Binaries], binaries: eclipsing, Astronomy and Astrophysics, 3rd-DAS, QC Physics, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, QB799, Astrophysics - Earth and Planetary Astrophysics
Abstract

The Transiting Exoplanet Survey Satellite (\tess) produces a large number of single-transit event candidates, since the mission monitors most stars for only $\sim$27\,days. Such candidates correspond to long-period planets or eclipsing binaries. Using the \tess\ Sector 1 full-frame images, we identified a 7750\,ppm single-transit event with a duration of 7\,hours around the moderately evolved F-dwarf star \tic\ (Tmag=10.23, \teff=6280$\pm{85}$\,K). Using archival WASP photometry we constrained the true orbital period to one of three possible values. We detected a subsequent transit-event with NGTS, which revealed the orbital period to be 38.20\,d. Radial velocity measurements from the CORALIE Spectrograph show the secondary object has a mass of $M_2$= $0.148\pm{0.003}$\,M$_{\odot}$, indicating this system is an F-M eclipsing binary. The radius of the M-dwarf companion is $R_2$ = $0.171\pm{0.003}$\,R$_{\odot}$, making this one of the most well characterised stars in this mass regime. We find that its radius is 2.3-$\sigma$ lower than expected from stellar evolution models., Comment: 6 pages, 5 Figures, 1 Table. Submitted to MNRAS letters

Published
2019

20. NGTS-6b: An Ultra Short Period Hot-Jupiter Orbiting an Old K Dwarf

Author

Heike Rauer, Samuel Gill, Szilard Csizmadia, Maximiliano Moyano, Philipp Eigmüller, Christopher A. Watson, Sarah L. Casewell, Jose I. Vines, Ruth Titz-Weider, Claudia Belardi, Benjamin F. Cooke, Juan Cabrera, George W. King, Anders Erikson, François Bouchy, Alexis M. S. Smith, Daniel Bayliss, Michael R. Goad, E. Foxell, Edward Gillen, James A. G. Jackman, Don Pollacco, Edward M. Bryant, M. G. Soto, Oliver Turner, Jack S. Acton, Richard G. West, James McCormac, Liam Raynard, Simon R. Walker, Peter J. Wheatley, Louise D. Nielsen, Didier Queloz, Rosanna H. Tilbrook, Stéphane Udry, Alexander Chaushev, Matthew R. Burleigh, James S. Jenkins, Tom Louden, and Joshua T. Briegal

Subjects
Extrasolare Planeten und Atmosphären, planets and satellites: detection, 010504 meteorology & atmospheric sciences, Gas giant, Population, FOS: Physical sciences, 01 natural sciences, Planet, 0103 physical sciences, Hot Jupiter, Transit (astronomy), education, planetary systems, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Physics, education.field_of_study, Leitungsbereich PF, Astronomy, Astronomy and Astrophysics, Planetary system, Photoevaporation, Orbit, 13. Climate action, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract

We report the discovery of a new ultra-short period hot Jupiter from the Next Generation Transit Survey. NGTS-6b orbits its star with a period of 21.17~h, and has a mass and radius of $1.330^{+0.024}_{-0.028}$\mjup\, and $1.271^{+0.197}_{-0.188}$\rjup\, respectively, returning a planetary bulk density of 0.711$^{+0.214}_{-0.136}$~g~cm$^{-3}$. Conforming to the currently known small population of ultra-short period hot Jupiters, the planet appears to orbit a metal-rich star ([Fe/H]$=+0.11\pm0.09$~dex). Photoevaporation models suggest the planet should have lost 5\% of its gaseous atmosphere over the course of the 9.6~Gyrs of evolution of the system. NGTS-6b adds to the small, but growing list of ultra-short period gas giant planets, and will help us to understand the dominant formation and evolutionary mechanisms that govern this population., 10 pages, 11 figures. Paper accepted for publication in MNRAS

Published
2019

21. NGTS-11 b (TOI-1847 b): A Transiting Warm Saturn Recovered from a TESS Single-transit Event

Author

Christopher A. Watson, Jose I. Vines, Philipp Eigmüller, Thomas Henning, Rafael Brahm, Richard G. West, James McCormac, Samuel Gill, Jack S. Acton, Benjamin F. Cooke, Liam Raynard, Daniel Bayliss, Heike Rauer, Maximiliano Moyano, Andrés Jordán, David R. Anderson, Monika Lendl, Don Pollacco, Michael R. Goad, Louise D. Nielsen, Matthew R. Burleigh, Néstor Espinoza, Alexis M. S. Smith, Edward M. Bryant, Maximilian N. Günther, Melissa J. Hobson, Edward Gillen, H. P. Osborn, Sarah L. Casewell, Rosanna H. Tilbrook, François Bouchy, Paula Sarkis, Aleisha Hogan, Felipe Alejandro Lagos Rojas, James S. Jenkins, Peter J. Wheatley, Nolan Grieves, Didier Queloz, Marcelo Tala Pinto, David J. Armstrong, Stéphane Udry, Gill, S [0000-0002-4259-0155], Wheatley, PJ [0000-0003-1452-2240], Cooke, BF [0000-0002-8824-9956], Jordán, A [0000-0002-5389-3944], Nielsen, LD [0000-0002-5254-2499], Bayliss, D [0000-0001-6023-1335], Anderson, DR [0000-0001-7416-7522], Vines, JI [0000-0002-1896-2377], Lendl, M [0000-0001-9699-1459], Armstrong, DJ [0000-0002-5080-4117], Brahm, R [0000-0002-9158-7315], Burleigh, MR [0000-0003-0684-7803], Casewell, SL [0000-0003-2478-0120], Espinoza, N [0000-0001-9513-1449], Gillen, E [0000-0003-2851-3070], Grieves, N [0000-0001-8105-0373], Günther, MN [0000-0002-3164-9086], Henning, T [0000-0002-1493-300X], Hobson, MJ [0000-0002-5945-7975], Jenkins, JS [0000-0003-2733-8725], Osborn, HP [0000-0002-4047-4724], Pollacco, D [0000-0001-9850-9697], Queloz, D [0000-0002-3012-0316], Sarkis, P [0000-0001-8128-3126], Smith, AMS [0000-0002-2386-4341], Udry, S [0000-0001-7576-6236], West, RG [0000-0001-6604-5533], and Apollo - University of Cambridge Repository

Subjects
Extrasolare Planeten und Atmosphären, astro-ph.SR, Extrasolar gas giants, 010504 meteorology & atmospheric sciences, Exoplanet astronomy, Gas giant, FOS: Physical sciences, 01 natural sciences, Photometry, Photometry (optics), Planet, High resolution spectroscopy, 0103 physical sciences, Exoplanet detection methods, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), QB, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Physics, Exoplanets, Astronomy, Astronomy and Astrophysics, Radius, Orbital period, Exoplanet, Radial velocity, Stars, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, astro-ph.EP, Astrophysics - Earth and Planetary Astrophysics
Abstract

We report the discovery of NGTS-11 b (=TOI-1847 b), a transiting Saturn in a 35.46-day orbit around a mid K-type star (Teff=5050 K). We initially identified the system from a single-transit event in a TESS full-frame image light-curve. Following seventy-nine nights of photometric monitoring with an NGTS telescope, we observed a second full transit of NGTS-11 b approximately one year after the TESS single-transit event. The NGTS transit confirmed the parameters of the transit signal and restricted the orbital period to a set of 13 discrete periods. We combined our transit detections with precise radial velocity measurements to determine the true orbital period and measure the mass of the planet. We find NGTS-11 b has a radius of 0.817+0.028-0.032 $R_J$, a mass of 0.344+0.092-0.073 $M_J$, and an equilibrium temperature of just 435+34-32 K, making it one of the coolest known transiting gas giants. NGTS-11 b is the first exoplanet to be discovered after being initially identified as a TESS single-transit event, and its discovery highlights the power of intense photometric monitoring in recovering longer-period transiting exoplanets from single-transit events., Comment: 8 pages, 3 Figures, 1 table. Accepted to ApJ letters

Published
2020
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