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39 results on '"Lienhard, F."'

1. Confronting compositional confusion through the characterisation of the sub-Neptune orbiting HD 77946

Author

Palethorpe, L., John, A. Anna, Mortier, A., Davoult, J., Wilson, T. G., Rice, K., Cameron, A. C., Alibert, Y., Buchhave, L. A., Malavolta, L., Cadman, J., López-Morales, M., Dumusque, X., Silva, A. M., Quinn, S. N., Van Eylen, V., Vissapragada, S., Affer, L., Charbonneau, D., Cosentino, R., Ghedina, A., Haywood, R. D., Latham, D. W., Lienhard, F., Fiorenzano, A. F. Martínez, Pedani, M., Pepe, F., Pinamonti, M., Sozzetti, A., Stalport, M., Udry, S., and Vanderburg, A.

Subjects
Astrophysics - Earth and Planetary Astrophysics
Abstract

We report on the detailed characterization of the HD 77946 planetary system. HD 77946 is an F5 ($M_*$ = 1.17 M$_{\odot}$, $R_*$ = 1.31 R$_{\odot}$) star, which hosts a transiting planet recently discovered by NASA's Transiting Exoplanet Survey Satellite (TESS), classified as TOI-1778 b. Using TESS photometry, high-resolution spectroscopic data from HARPS-N, and photometry from CHEOPS, we measure the radius and mass from the transit and RV observations, and find that the planet, HD 77946 b, orbits with period $P_{\rm b}$ = $6.527282_{-0.000020}^{+0.000015}$ d, has a mass of $M_{\rm b} = 8.38\pm{1.32}$M$_\oplus$, and a radius of $R_{\rm b} = 2.705_{-0.081}^{+0.086}$R$_\oplus$. From the combination of mass and radius measurements, and the stellar chemical composition, the planet properties suggest that HD 77946 b is a sub-Neptune with a $\sim$1\% H/He atmosphere. However, a degeneracy still exists between water-world and silicate/iron-hydrogen models, and even though interior structure modelling of this planet favours a sub-Neptune with a H/He layer that makes up a significant fraction of its radius, a water-world composition cannot be ruled out, as with $T_{\rm eq} = 1248^{+40}_{-38}~$K, water may be in a supercritical state. The characterisation of HD 77946 b, adding to the small sample of well-characterised sub-Neptunes, is an important step forwards on our journey to understanding planetary formation and evolution pathways. Furthermore, HD 77946 b has one of the highest transmission spectroscopic metrics for small planets orbiting hot stars, thus transmission spectroscopy of this key planet could prove vital for constraining the compositional confusion that currently surrounds small exoplanets., Comment: 19 pages, 13 figures, 5 tables. Published in MNRAS

Published
2024
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2. Unsigned magnetic flux proxy from solar optical intensity spectra

Author

Lienhard, F., Mortier, A., Cegla, H. M., Cameron, A. Collier, Klein, B., and Watson, C. A.

Subjects
Astrophysics - Earth and Planetary Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - Solar and Stellar Astrophysics
Abstract

The photospheric unsigned magnetic flux has been shown to be highly correlated with radial velocity (RV) variations caused by solar surface activity. This activity indicator is therefore a prime candidate to unlock the potential of RV surveys to discover Earth twins orbiting Sun-like stars. We show for the first time how a precise proxy of the unsigned magnetic flux ($\Delta\alpha B^2$) can be obtained from Sun-as-a-star intensity spectra by harnessing the magnetic information contained in over 4000 absorption lines in the wavelength range from 380 to 690 nm. This novel activity proxy can thus be obtained from the same spectra from which RVs are routinely extracted. We derived $\Delta\alpha B^2$ from 500 randomly selected spectra from the HARPS-N public solar data set, which spans from 2015 to 2018. We compared our estimates with the unsigned magnetic flux values from the Solar Dynamics Observatory (SDO) finding excellent agreement (median absolute deviation: 4.9 per cent). The extracted indicator $\Delta\alpha B^2$ correlates with SDO's unsigned magnetic flux estimates on the solar rotational timescale (Pearson correlation coefficient 0.67) and on the three-year timescale of our data set (correlation coefficient 0.91). We find correlations of $\Delta\alpha B^2$ with the HARPS-N solar RV variations of 0.49 on the rotational timescale and 0.78 on the three-year timescale. The Pearson correlation of $\Delta\alpha B^2$ with the RVs is found to be greater than the correlation of the classical activity indicators with the RVs. For solar-type stars, $\Delta\alpha B^2$ therefore represents the best simultaneous activity proxy known to date., Comment: Typo corrected in Eq. 6. Note added to Eq. 16 highlighting its similarity to the second derivative. Results unchanged. 17 pages, 10 figures, published in MNRAS

Published
2023
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3. Multi-Mask Least-Squares Deconvolution: Extracting RVs using tailored masks

Author

Lienhard, F., Mortier, A., Buchhave, L., Cameron, A. Collier, Lopez-Morales, M., Sozzetti, A., Watson, C. A., and Cosentino, R.

Subjects
Astrophysics - Earth and Planetary Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - Solar and Stellar Astrophysics
Abstract

To push the radial velocity (RV) exoplanet detection threshold, it is crucial to find more reliable radial velocity extraction methods. The Least-Squares Deconvolution (LSD) technique has been used to infer the stellar magnetic flux from spectropolarimetric data for the past two decades. It relies on the assumption that stellar absorption lines are similar in shape. Although this assumption is simplistic, LSD provides a good model for intensity spectra and likewise an estimate for their Doppler shift. We present the Multi-Mask Least-Squares Deconvolution (MM-LSD) RV extraction pipeline which extracts the radial velocity from two-dimensional echelle-order spectra using LSD with multiple tailored masks after continuum normalisation and telluric absorption line correction. The flexibility of LSD allows to exclude spectral lines or pixels at will, providing a means to exclude variable lines or pixels affected by instrumental problems. The MM-LSD pipeline was tested on HARPS-N data for the Sun and selected well-observed stars with 5.7 < Vmag < 12.6. For FGK-type stars with median signal-to-noise above 100, the pipeline delivered RV time series with on average 12 per cent lower scatter as compared to the HARPS-N RV extraction pipeline based on the Cross-Correlation Function technique. The MM-LSD pipeline may be used as a standalone RV code, or modified and extended to extract a proxy for the magnetic field strength., Comment: Accepted for publication in MNRAS. Code available on github: https://github.com/florian-lienhard/MM-LSD. 16 pages, 15 figures

Published
2022
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4. An unusually low density ultra-short period super-Earth and three mini-Neptunes around the old star TOI-561

Author

Lacedelli, G., Malavolta, L., Borsato, L., Piotto, G., Nardiello, D., Mortier, A., Stalport, M., Cameron, A. Collier, Poretti, E., Buchhave, L. A., López-Morales, M., Nascimbeni, V., Wilson, T. G., Udry, S., Latham, D. W., Bonomo, A. S., Damasso, M., Dumusque, X., Jenkins, J. M., Lovis, C., Rice, K., Sasselov, D., Winn, J. N., Andreuzzi, G., Cosentino, R., Charbonneau, D., Di Fabrizio, L., Fiorenzano, A. F. Martinez, Ghedina, A., Harutyunyan, A., Lienhard, F., Micela, G., Molinari, E., Pagano, I., Pepe, F., Phillips, D. F., Pinamonti, M., Ricker, G., Scandariato, G., Sozzetti, A., and Watson, C. A.

Subjects
Astrophysics - Earth and Planetary Astrophysics, Astrophysics - Solar and Stellar Astrophysics
Abstract

Based on HARPS-N radial velocities (RVs) and TESS photometry, we present a full characterisation of the planetary system orbiting the late G dwarf TOI-561. After the identification of three transiting candidates by TESS, we discovered two additional external planets from RV analysis. RVs cannot confirm the outer TESS transiting candidate, which would also make the system dynamically unstable. We demonstrate that the two transits initially associated with this candidate are instead due to single transits of the two planets discovered using RVs. The four planets orbiting TOI-561 include an ultra-short period (USP) super-Earth (TOI-561 b) with period $P_{\rm b} = 0.45$ d, mass $M_{\rm b} =1.59 \pm 0.36$ M$_\oplus$ and radius $R_{\rm b}=1.42 \pm 0.07$ R$_\oplus$, and three mini-Neptunes: TOI-561 c, with $P_{\rm c} = 10.78$ d, $M_{\rm c} = 5.40 \pm 0.98$ M$_\oplus$, $R_{\rm c}= 2.88 \pm 0.09$ R$_\oplus$; TOI-561 d, with $P_{\rm d} = 25.6$ d, $M_{\rm d} = 11.9 \pm 1.3$ M$_\oplus$, $R_{\rm d} = 2.53 \pm 0.13$ R$_\oplus$; and TOI-561 e, with $P_{\rm e} = 77.2$ d, $M_{\rm e} = 16.0 \pm 2.3$ M$_\oplus$, $R_{\rm e} = 2.67 \pm 0.11$ R$_\oplus$. Having a density of $3.0 \pm 0.8$ g cm$^{-3}$, TOI-561 b is the lowest density USP planet known to date. Our N-body simulations confirm the stability of the system and predict a strong, anti-correlated, long-term transit time variation signal between planets d and e. The unusual density of the inner super-Earth and the dynamical interactions between the outer planets make TOI-561 an interesting follow-up target., Comment: 20 pages, 12 figures. Accepted for publication in MNRAS

Published
2020
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5. Global Analysis of the TRAPPIST Ultra-Cool Dwarf Transit Survey

Author

Lienhard, F., Queloz, D., Gillon, M., Burdanov, A., Delrez, L., Ducrot, E., Handley, W., Jehin, E., Murray, C. A., Triaud, A. H. M. J., Gillen, E., Mortier, A., and Rackham, B. V.

Subjects
Astrophysics - Earth and Planetary Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - Solar and Stellar Astrophysics
Abstract

We conducted a global analysis of the TRAPPIST Ultra-Cool Dwarf Transit Survey - a prototype of the SPECULOOS transit search conducted with the TRAPPIST-South robotic telescope in Chile from 2011 to 2017 - to estimate the occurrence rate of close-in planets such as TRAPPIST-1b orbiting ultra-cool dwarfs. For this purpose, the photometric data of 40 nearby ultra-cool dwarfs were reanalysed in a self-consistent and fully automated manner starting from the raw images. The pipeline developed specifically for this task generates differential light curves, removes non-planetary photometric features and stellar variability, and searches for transits. It identifies the transits of TRAPPIST-1b and TRAPPIST-1c without any human intervention. To test the pipeline and the potential output of similar surveys, we injected planetary transits into the light curves on a star-by-star basis and tested whether the pipeline is able to detect them. The achieved photometric precision enables us to identify Earth-sized planets orbiting ultra-cool dwarfs as validated by the injection tests. Our planet-injection simulation further suggests a lower limit of 10 per cent on the occurrence rate of planets similar to TRAPPIST-1b with a radius between 1 and 1.3 $R_\oplus$ and the orbital period between 1.4 and 1.8 days., Comment: Accepted for publication in MNRAS, 21 pages, 18 figures, 3 tables

Published
2020
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6. Photometry and Performance of SPECULOOS-South

Author

Murray, C. A., Delrez, L., Pedersen, P. P., Queloz, D., Gillon, M., Burdanov, A., Ducrot, E., Garcia, L. J., Lienhard, F., Demory, B. O., Jehin, E., McCormac, J., Sebastian, D., Sohy, S., Thompson, S. J., Triaud, A. H. M. J., Grootel, V. V., Günther, M. N., and Huang, C. X.

Subjects
Astrophysics - Earth and Planetary Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - Solar and Stellar Astrophysics
Abstract

SPECULOOS-South, an observatory composed of four independent 1m robotic telescopes, located at ESO Paranal, Chile, started scientific operation in January 2019. This Southern Hemisphere facility operates as part of SPECULOOS, an international network of 1m-class telescopes surveying for transiting terrestrial planets around the nearest and brightest ultra-cool dwarfs. To automatically and efficiently process the observations of SPECULOOS-South, and to deal with the specialised photometric requirements of ultra-cool dwarf targets, we present our automatic pipeline. This pipeline includes an algorithm for automated differential photometry and an extensive correction technique for the effects of telluric water vapour, using ground measurements of the precipitable water vapour. Observing very red targets in the near-infrared can result in photometric systematics in the differential lightcurves, related to the temporally-varying, wavelength-dependent opacity of the Earth's atmosphere. These systematics are sufficient to affect the daily quality of the lightcurves, the longer time-scale variability study of our targets and even mimic transit-like signals. Here we present the implementation and impact of our water vapour correction method. Using the 179 nights and 98 targets observed in the I+z' filter by SPECULOOS-South since January 2019, we show the impressive photometric performance of the facility (with a median precision of ~1.5 mmag for 30-min binning of the raw, non-detrended lightcurves) and assess its detection potential. We compare simultaneous observations with SPECULOOS-South and TESS, to show that we readily achieve high-precision, space-level photometry for bright, ultra-cool dwarfs, highlighting SPECULOOS-South as the first facility of its kind., Comment: Accepted for publication in MNRAS, 13 pages, 12 figures, 1 table

Published
2020
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7. Trio of super-Earth candidates orbiting K-dwarf HD 48948: a new habitable zone candidate.

Author

Dalal, S, Rescigno, F, Cretignier, M, Anna John, A, Majidi, F Z, Malavolta, L, Mortier, A, Pinamonti, M, Buchhave, L A, Haywood, R D, Sozzetti, A, Dumusque, X, Lienhard, F, Rice, K, Vanderburg, A, Lakeland, B, Bonomo, A S, Cameron, A Collier, Damasso, M, and Affer, L

Subjects
KRIGING, DWARF stars, ORBITS (Astronomy), STELLAR activity, STELLAR magnitudes, STELLAR rotation, EXTRACTION techniques
Abstract

We present the discovery of three super-Earth candidates orbiting HD 48948, a bright K-dwarf star with an apparent magnitude of |$m_V$|  = 8.58 mag. As part of the HARPS-N Rocky Planet Search programme, we collect 189 high-precision radial velocity measurements using the HARPS-N spectrograph from 2013 October 6, to 2023 April 16. Various methodologies are applied to extract the radial velocities from the spectra, and we conduct a comprehensive comparative analysis of the outcomes obtained through these diverse extraction techniques. To ensure the robustness of our findings, we employ several methods to address stellar variability, with a focus on Gaussian Process regression. To account for the impact of stellar variability and correlated noise in the radial velocity data set, we include activity indicators, such as |$\log R^{^{\prime }}_{\mathrm{HK}}$| and bisector span, in the multidimensional Gaussian Process regression. Our analysis reveals three planetary candidates with orbital periods of 7.3, 38, and 151 d, and minimum masses estimated at |$4.88 \pm 0.21$| M |$_{\oplus }$|⁠ , |$7.27 \pm 0.70$| M |$_{\oplus }$|⁠ , and |$10.59 \pm 1.00$| M |$_{\oplus }$|⁠ , respectively. The outermost planet resides within the (temperate) habitable zone, positioned at a projected distance of |$0.029\,{\rm arcsec}$| from its star. Given the close proximity of this planetary system, situated at a distance of 16.8 parsecs, HD 48498 emerges as a promising target (closest super-Earth around FGK stars) for future high-contrast direct imaging and high-resolution spectroscopic studies. [ABSTRACT FROM AUTHOR]

Published
2024
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9. Correction to: Trio of super-Earth candidates orbiting K-dwarf HD 48948: a new habitable zone candidate.

Author

Dalal, S, Rescigno, F, Cretignier, M, Anna John, A, Majidi, F Z, Malavolta, L, Mortier, A, Pinamonti, M, Buchhave, L A, Haywood, R D, Sozzetti, A, Dumusque, X, Lienhard, F, Rice, K, Vanderburg, A, Lakeland, B, Bonomo, A S, Cameron, A Collier, Damasso, M, and Affer, L

Subjects
STELLAR rotation, HABITABLE zone (Outer space), NATURAL satellites, MATHEMATICAL errors, SPECTROGRAPHS
Published
2024
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10. An unusually low density ultra-short period super-Earth and three mini-Neptunes around the old star TOI-561

Author

Lacedelli, G., Malavolta, L., Borsato, L., Piotto, G., Nardiello, D., Mortier, A., Stalport, M., Cameron, A. Collier, Poretti, E., Buchhave, Lars A., López-Morales, M., Nascimbeni, V., Wilson, T. G., Udry, S., Latham, D. W., Bonomo, A. S., Damasso, M., Dumusque, X., Jenkins, J. M., Lovis, C., Rice, K., Sasselov, D., Winn, J. N., Andreuzzi, G., Cosentino, R., Charbonneau, D., Di Fabrizio, L., Martinez Fiorenzano, A. F., Ghedina, A., Harutyunyan, A., Lienhard, F., Micela, G., Molinari, E., Pagano, I., Pepe, F., Phillips, D. F., Pinamonti, M., Ricker, G., Scandariato, G., Sozzetti, A., Watson, C. A., Lacedelli, G., Malavolta, L., Borsato, L., Piotto, G., Nardiello, D., Mortier, A., Stalport, M., Cameron, A. Collier, Poretti, E., Buchhave, Lars A., López-Morales, M., Nascimbeni, V., Wilson, T. G., Udry, S., Latham, D. W., Bonomo, A. S., Damasso, M., Dumusque, X., Jenkins, J. M., Lovis, C., Rice, K., Sasselov, D., Winn, J. N., Andreuzzi, G., Cosentino, R., Charbonneau, D., Di Fabrizio, L., Martinez Fiorenzano, A. F., Ghedina, A., Harutyunyan, A., Lienhard, F., Micela, G., Molinari, E., Pagano, I., Pepe, F., Phillips, D. F., Pinamonti, M., Ricker, G., Scandariato, G., Sozzetti, A., and Watson, C. A.

Abstract

Based on HARPS-N radial velocities (RVs) and TESS photometry, we present a full characterisation of the planetary system orbiting the late G dwarf TOI-561. After the identification of three transiting candidates by TESS, we discovered two additional external planets from RV analysis. RVs cannot confirm the outer TESS transiting candidate, which would also make the system dynamically unstable. We demonstrate that the two transits initially associated with this candidate are instead due to single transits of the two planets discovered using RVs. The four planets orbiting TOI-561 include an ultra-shortperiod (USP) super-Earth (TOI-561 b) with period Pb=0.45 d, mass Mb=1.59±0.36 M⊕ and radius Rb=1.42±0.07R⊕, and three mini-Neptunes: TOI-561 c, with Pc=10.78 d,Mc=5.40±0.98 M⊕, Rc=2.88±0.09 R⊕;TOI-561 d, with Pd=25.6 d, Md=11.9±1.3 M⊕,Rd=2.53±0.13 R⊕; and TOI-561 e, with Pe=77.2d, Me=16.0±2.3 M⊕, Re=2.67±0.11R⊕. Having a density of 3.0±0.8 g cm−3, TOI-561 b is the lowest density USP planet known to date. Our N-body simulations confirm the stability of the system and predict a strong, anti-correlated, long-term transit time variation signal between planets d and e. The unusual density ofthe inner super-Earth and the dynamical interactions between the outer planets make TOI-561 an interesting follow-up target.

Published
2021

11. Multi-mask least-squares deconvolution: extracting RVs using tailored masks.

Author

Lienhard, F, Mortier, A, Buchhave, L, Collier Cameron, A, López-Morales, M, Sozzetti, A, Watson, C A, and Cosentino, R

Subjects
MAGNETIC flux density, DOPPLER effect, MAGNETIC flux, SPECTRAL lines, STELLAR magnetic fields, DECONVOLUTION (Mathematics)
Abstract

To push the radial velocity (RV) exoplanet detection threshold, it is crucial to find more reliable RV extraction methods. The least-squares deconvolution (LSD) technique has been used to infer the stellar magnetic flux from spectropolarimetric data for the past two decades. It relies on the assumption that stellar absorption lines are similar in shape. Although this assumption is simplistic, LSD provides a good model for intensity spectra and likewise an estimate for their Doppler shift. We present the multi-mask least-squares deconvolution (MM-LSD) RV extraction pipeline that extracts the RV from two-dimensional echelle-order spectra using LSD with multiple tailored masks after continuum normalization and telluric absorption line correction. The flexibility of LSD allows to exclude spectral lines or pixels at will, providing a means to exclude variable lines or pixels affected by instrumental problems. The MM-LSD pipeline was tested on HARPS-N data for the Sun and selected well-observed stars with 5.7 < V mag < 12.6. For FGK-type stars with median signal-to-noise ratio above 100, the pipeline delivered RV time series with on average 12 per cent lower scatter as compared to the HARPS-N RV extraction pipeline based on the cross-correlation function technique. The MM-LSD pipeline may be used as a standalone RV code, or modified and extended to extract a proxy for the magnetic field strength. [ABSTRACT FROM AUTHOR]

Published
2022
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12. Toi-1235 b: A keystone super-earth for testing radius valley emergence models around early m dwarfs

Author

Cloutier, R, Rodriguez, JE, Irwin, J, Charbonneau, D, Stassun, KG, Mortier, A, Latham, DW, Isaacson, H, Howard, AW, Udry, S, Wilson, TG, Watson, CA, Pinamonti, M, Lienhard, F, Giacobbe, P, Guerra, P, Collins, KA, Beiryla, A, Esquerdo, GA, Matthews, E, Matson, RA, Howell, SB, Furlan, E, Crossfield, IJM, Winters, JG, Nava, C, Ment, K, Lopez, ED, Ricker, G, Vanderspek, R, Seager, S, Jenkins, JM, Ting, EB, Tenenbaum, P, Sozzetti, A, Sha, L, Ségransan, D, Schlieder, JE, Sasselov, D, Roy, A, Robertson, P, Rice, K, Poretti, E, Piotto, G, Phillips, D, Pepper, J, Pepe, F, Molinari, E, Mocnik, T, Micela, G, Mayor, M, Martinez Fiorenzano, AF, Mallia, F, Lubin, J, Lovis, C, López-Morales, M, Kosiarek, MR, Kielkopf, JF, Kane, Jensen, ELN, Isopi, G, Huber, D, Hill, ML, Harutyunyan, A, Gonzales, E, Giacalone, S, Ghedina, A, Ercolino, A, Dumusque, X, Dressing, CD, Damasso, M, Dalba, PA, Cosentino, R, Conti, DM, Colón, KD, Collins, KI, Cameron, AC, Ciardi, D, Christiansen, J, Chontos, A, Cecconi, M, Caldwell, DA, Burke, C, Buchhave, L, Beichman, C, Behmard, A, Beard, C, Akana Murphy, JM, Cloutier, R [0000-0001-5383-9393], Rodriguez, JE [0000-0001-8812-0565], Charbonneau, D [0000-0002-9003-484X], Stassun, KG [0000-0002-3481-9052], Mortier, A [0000-0001-7254-4363], Latham, DW [0000-0001-9911-7388], Isaacson, H [0000-0002-0531-1073], Howard, AW [0000-0001-8638-0320], Udry, S [0000-0001-7576-6236], Collins, KA [0000-0001-6588-9574], Beiryla, A [0000-0001-6637-5401], Esquerdo, GA [0000-0002-9789-5474], Matthews, E [0000-0003-0593-1560], Matson, RA [0000-0001-7233-7508], Howell, SB [0000-0002-2532-2853], Winters, JG [0000-0001-6031-9513], Nava, C [0000-0001-8838-3883], Ment, K [0000-0001-5847-9147], Ricker, G [0000-0003-2058-6662], Vanderspek, R [0000-0001-6763-6562], Seager, S [0000-0002-6892-6948], Jenkins, JM [0000-0002-4715-9460], Ting, EB [0000-0002-8219-9505], Tenenbaum, P [0000-0002-1949-4720], Sozzetti, A [0000-0002-7504-365X], Sha, L [0000-0001-5401-8079], Ségransan, D [0000-0003-2355-8034], Schlieder, JE [0000-0001-5347-7062], Sasselov, D [0000-0001-7014-1771], Roy, A [0000-0001-8127-5775], Robertson, P [0000-0003-0149-9678], Poretti, E [0000-0003-1200-0473], Piotto, G [0000-0002-9937-6387], Pepper, J [0000-0002-3827-8417], Molinari, E [0000-0002-1742-7735], Mocnik, T [0000-0003-4603-556X], Micela, G [0000-0002-9900-4751], Lubin, J [0000-0001-8342-7736], López-Morales, M [0000-0003-3204-8183], Kielkopf, JF [0000-0003-0497-2651], Kane, SR [0000-0002-7084-0529], Jensen, ELN [0000-0002-4625-7333], Huber, D [0000-0001-8832-4488], Hill, ML [0000-0002-0139-4756], Giacalone, S [0000-0002-8965-3969], Ghedina, A [0000-0003-4702-5152], Dumusque, X [0000-0002-9332-2011], Dressing, CD [0000-0001-8189-0233], Dalba, PA [0000-0002-4297-5506], Cosentino, R [0000-0003-1784-1431], Conti, DM [0000-0003-2239-0567], Colón, KD [0000-0001-8020-7121], Collins, KI [0000-0003-2781-3207], Ciardi, D [0000-0002-5741-3047], Christiansen, J [0000-0002-8035-4778], Chontos, A [0000-0003-1125-2564], Caldwell, DA [0000-0003-1963-9616], Burke, C [0000-0002-7754-9486], Buchhave, L [0000-0003-1605-5666], Behmard, A [0000-0003-0012-9093], Beard, C [0000-0001-7708-2364], Akana Murphy, JM [0000-0001-8898-8284], and Apollo - University of Cambridge Repository

Subjects
Radial velocity, Exoplanet formation, Transit photometry, M dwarf stars, Exoplanet structure
Abstract

Small planets on close-in orbits tend to exhibit envelope mass fractions of either effectively zero or up to a few percent depending on their size and orbital period. Models of thermally-driven atmospheric mass loss and of terrestrial planet formation in a gas-poor environment make distinct predictions regarding the location of this rocky/non-rocky transition in period-radius space. Here we present the confirmation of TOI-1235 b ($P=3.44$ days, $r_p=1.738^{+0.087}_{-0.076}$ R$_{\oplus}$), a planet whose size and period are intermediate between the competing model predictions, thus making the system an important test case for emergence models of the rocky/non-rocky transition around early M dwarfs ($R_s=0.630\pm 0.015$ R$_{\odot}$, $M_s=0.640\pm 0.016$ M$_{\odot}$). We confirm the TESS planet discovery using reconnaissance spectroscopy, ground-based photometry, high-resolution imaging, and a set of 38 precise radial-velocities from HARPS-N and HIRES. We measure a planet mass of $6.91^{+0.75}_{-0.85}$ M$_{\oplus}$ which implies an iron core mass fraction of $20^{+15}_{-12}$% in the absence of a gaseous envelope. The bulk composition of TOI-1235 b is therefore consistent with being Earth-like and we constrain a H/He envelope mass fraction to be $

Published
2020

13. An unusually low density ultra-short period super-Earth and three mini-Neptunes around the old star TOI-561

Author

Lacedelli, G, primary, Malavolta, L, additional, Borsato, L, additional, Piotto, G, additional, Nardiello, D, additional, Mortier, A, additional, Stalport, M, additional, Collier Cameron, A, additional, Poretti, E, additional, Buchhave, L A, additional, López-Morales, M, additional, Nascimbeni, V, additional, Wilson, T G, additional, Udry, S, additional, Latham, D W, additional, Bonomo, A S, additional, Damasso, M, additional, Dumusque, X, additional, Jenkins, J M, additional, Lovis, C, additional, Rice, K, additional, Sasselov, D, additional, Winn, J N, additional, Andreuzzi, G, additional, Cosentino, R, additional, Charbonneau, D, additional, Di Fabrizio, L, additional, Martnez Fiorenzano, A F, additional, Ghedina, A, additional, Harutyunyan, A, additional, Lienhard, F, additional, Micela, G, additional, Molinari, E, additional, Pagano, I, additional, Pepe, F, additional, Phillips, D F, additional, Pinamonti, M, additional, Ricker, G, additional, Scandariato, G, additional, Sozzetti, A, additional, and Watson, C A, additional

Published
2020
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14. Global analysis of the TRAPPIST Ultra-Cool Dwarf Transit Survey

Author

Lienhard, F, primary, Queloz, D, additional, Gillon, M, additional, Burdanov, A, additional, Delrez, L, additional, Ducrot, E, additional, Handley, W, additional, Jehin, E, additional, Murray, C A, additional, Triaud, A H M J, additional, Gillen, E, additional, Mortier, A, additional, and Rackham, B V, additional

Published
2020
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15. Photometry and performance of SPECULOOS-South

Author

Murray, C A, primary, Delrez, L, primary, Pedersen, P P, primary, Queloz, D, primary, Gillon, M, primary, Burdanov, A, primary, Ducrot, E, primary, Garcia, L J, primary, Lienhard, F, primary, Demory, B O, primary, Jehin, E, primary, McCormac, J, primary, Sebastian, D, primary, Sohy, S, primary, Thompson, S J, primary, Triaud, A H M J, primary, Grootel, V V, primary, Günther, M N, primary, and Huang, C X, primary

Published
2020
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22. The French Military influenza surveillance system (MISS): overview of epidemiological and virological results during four influenza seasons--2008-2012

Author

Bigaillon C, S. Duron, Miss staff, Védy S, Catherine Verret, A. Merens, Dubrous P, R. Migliani, Berbineau L, Le Guen P, Garnotel E, A. Mayet, Jean-Baptiste Meynard, X. Deparis, R. Haus-Cheymol, Brisou P, and Lienhard F

Subjects
Adult, Male, medicine.medical_specialty, Medical consultation, Viral infection, Virus, Young Adult, Influenza A Virus, H1N1 Subtype, Epidemiology, Pandemic, Influenza, Human, medicine, Humans, Pandemics, Respiratory Tract Infections, business.industry, Influenza A Virus, H3N2 Subtype, Respiratory infection, Outbreak, General Medicine, Virology, Military Personnel, Epidemiological Monitoring, Human mortality from H5N1, Female, France, business, Demography
Abstract

QUESTION UNDER STUDY: Influenza is a viral infection caused by a pathogen with considerable ability for genetic mutation, which is responsible for seasonal outbreaks as well as pandemics. This article presents the results of epidemiological and virological monitoring of four successive influenza outbreaks in the French armed forces, for the period 2008 to 2012. METHODS: The main events monitored were acute respiratory infection (ARI). Weekly incidence rates were calculated by relating cases to the number of servicepersons monitored. RESULTS: In continental France, the incidence rates for ARI and for medical consultation attributable to influenza were highest during the pandemic and decreased to reach their lowest values in 2010–2011 and 2011–2012. In terms of virological results, the 2008–2009 outbreak was mainly due to the A(H3N2) virus, while the 2009–2010 pandemic and the following season saw the emergence of the A(H1N1) pdm09 strain. The last season 2011–2012 was characterised by a predominant circulation of A(H3N2) viruses. CONCLUSIONS: Despite some limitations, the MISS represents a good source of information about influenza in young people. Virological results are compatible with those reported by most other influenza surveillance networks, but could be improved by a better knowledge of the other respiratory viruses in circulation in the military community.

Published
2013

23. The French Military influenza surveillance system (MISS): overview of epidemiological and virological results during four influenza seasons – 2008–2012

Author

Duron, S, primary, Mayet, A, additional, Lienhard, F, additional, Haus-Cheymol, R, additional, Verret, C, additional, Védy, S, additional, Le, Guen, additional, Berbineau, L, additional, Brisou, P, additional, Dubrous, P, additional, Garnotel, E, additional, Meynard, JB, additional, Deparis, X, additional, Mérens, A, additional, Bigaillon, C, additional, and Migliani, R, additional

Published
2013
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28. An unusually low density ultra-short period super-Earth and three mini-Neptunes around the old star TOI-561

Author

Lacedelli, G, Malavolta, L, Borsato, L, Piotto, G, Nardiello, D, Mortier, A, Stalport, M, Collier Cameron, A, Poretti, E, Buchhave, LA, López-Morales, M, Nascimbeni, V, Wilson, TG, Udry, S, Latham, DW, Bonomo, AS, Damasso, M, Dumusque, X, Jenkins, JM, Lovis, C, Rice, K, Sasselov, D, Winn, JN, Andreuzzi, G, Cosentino, R, Charbonneau, D, Di Fabrizio, L, Martnez Fiorenzano, AF, Ghedina, A, Harutyunyan, A, Lienhard, F, Micela, G, Molinari, E, Pagano, I, Pepe, F, Phillips, DF, Pinamonti, M, Ricker, G, Scandariato, G, Sozzetti, A, and Watson, CA

Subjects
techniques: photometric, planets and satellites: detection, stars: individual: TOI-561 (TIC 377064495, Gaia DR2 3850421005290172416), 13. Climate action, techniques: radial velocities, planets and satellites: composition
Abstract

Based on HARPS-N radial velocities (RVs) and TESS photometry, we present a full characterisation of the planetary system orbiting the late G dwarf TOI-561. After the identification of three transiting candidates by TESS, we discovered two additional external planets from RV analysis. RVs cannot confirm the outer TESS transiting candidate, which would also make the system dynamically unstable. We demonstrate that the two transits initially associated with this candidate are instead due to single transits of the two planets discovered using RVs. The four planets orbiting TOI-561 include an ultra-short period (USP) super-Earth (TOI-561 b) with period $P_{\rm b} = 0.45$ d, mass $M_{\rm b} =1.59 \pm 0.36$ M$_\oplus$ and radius $R_{\rm b}=1.42 \pm 0.07$ R$_\oplus$, and three mini-Neptunes: TOI-561 c, with $P_{\rm c} = 10.78$ d, $M_{\rm c} = 5.40 \pm 0.98$ M$_\oplus$, $R_{\rm c}= 2.88 \pm 0.09$ R$_\oplus$; TOI-561 d, with $P_{\rm d} = 25.6$ d, $M_{\rm d} = 11.9 \pm 1.3$ M$_\oplus$, $R_{\rm d} = 2.53 \pm 0.13$ R$_\oplus$; and TOI-561 e, with $P_{\rm e} = 77.2$ d, $M_{\rm e} = 16.0 \pm 2.3$ M$_\oplus$, $R_{\rm e} = 2.67 \pm 0.11$ R$_\oplus$. Having a density of $3.0 \pm 0.8$ g cm$^{-3}$, TOI-561 b is the lowest density USP planet known to date. Our N-body simulations confirm the stability of the system and predict a strong, anti-correlated, long-term transit time variation signal between planets d and e. The unusual density of the inner super-Earth and the dynamical interactions between the outer planets make TOI-561 an interesting follow-up target.

29. Photometry and performance of SPECULOOS-South

Author

Murray, CA, Delrez, L, Pedersen, PP, Queloz, D, Gillon, M, Burdanov, A, Ducrot, E, Garcia, LJ, Lienhard, F, Demory, BO, Jehin, E, McCormac, J, Sebastian, D, Sohy, S, Thompson, SJ, Triaud, AHMJ, Grootel, Günther, MN, and Huang, CX

Subjects
techniques: photometric, planets and satellites: detection, 13. Climate action, atmospheric effects
Abstract

SPECULOOS-South, an observatory composed of four independent 1m robotic telescopes, located at ESO Paranal, Chile, started scientific operation in January 2019. This Southern Hemisphere facility operates as part of SPECULOOS, an international network of 1m-class telescopes surveying for transiting terrestrial planets around the nearest and brightest ultra-cool dwarfs. To automatically and efficiently process the observations of SPECULOOS-South, and to deal with the specialised photometric requirements of ultra-cool dwarf targets, we present our automatic pipeline. This pipeline includes an algorithm for automated differential photometry and an extensive correction technique for the effects of telluric water vapour, using ground measurements of the precipitable water vapour. Observing very red targets in the near-infrared can result in photometric systematics in the differential lightcurves, related to the temporally-varying, wavelength-dependent opacity of the Earth's atmosphere. These systematics are sufficient to affect the daily quality of the lightcurves, the longer time-scale variability study of our targets and even mimic transit-like signals. Here we present the implementation and impact of our water vapour correction method. Using the 179 nights and 98 targets observed in the I+z' filter by SPECULOOS-South since January 2019, we show the impressive photometric performance of the facility (with a median precision of ~1.5 mmag for 30-min binning of the raw, non-detrended lightcurves) and assess its detection potential. We compare simultaneous observations with SPECULOOS-South and TESS, to show that we readily achieve high-precision, space-level photometry for bright, ultra-cool dwarfs, highlighting SPECULOOS-South as the first facility of its kind.

30. Photometry and performance of SPECULOOS-South

Author

Murray, C A, Delrez, L, Pedersen, P P, Queloz, D, Gillon, M, Burdanov, A, Ducrot, E, Garcia, L J, Lienhard, F, Demory, B. O., Jehin, E, McCormac, J, Sebastian, D, Sohy, S, Thompson, S J, Triaud, A H M J, Grootel, V V, Günther, M N, and Huang, C X

Subjects
13. Climate action, 530 Physics, 520 Astronomy, 500 Science
Abstract

SPECULOOS-South, an observatory composed of four independent 1-m robotic telescopes, located at ESO Paranal, Chile, started scientific operation in 2019 January. This Southern hemisphere facility operates as part of the Search for Habitable Planets EClipsing ULtra-cOOl Stars (SPECULOOS), an international network of 1-m-class telescopes surveying for transiting terrestrial planets around the nearest and brightest ultracool dwarfs (UCDs). To automatically and efficiently process the observations of SPECULOOS-South, and to deal with the specialized photometric requirements of UCD targets, we present our automatic pipeline. This pipeline includes an algorithm for automated differential photometry and an extensive correction technique for the effects of telluric water vapour, using ground measurements of the precipitable water vapour. Observing very red targets in the near-infrared can result in photometric systematics in the differential light curves, related to the temporally-varying, wavelength-dependent opacity of the Earth’s atmosphere. These systematics are sufficient to affect the daily quality of the light curves, the longer time-scale variability study of our targets and even mimic transit-like signals. Here we present the implementation and impact of our water vapour correction method. Using the 179 nights and 98 targets observed in the I + z′ filter by SPECULOOS-South since 2019 January, we show the impressive photometric performance of the facility (with a median precision of ∼1.5 mmag for 30-min binning of the raw, non-detrended light curves) and assess its detection potential. We compare simultaneous observations with SPECULOOS-South and TESS, to show that we readily achieve high-precision, space-level photometry for bright, UCDs, highlighting SPECULOOS-South as the first facility of its kind.

31. Global analysis of the TRAPPIST Ultra-Cool Dwarf Transit Survey

Author

Lienhard, F, Queloz, D, Gillon, M, Burdanov, A, Delrez, L, Ducrot, E, Handley, W, Jehin, E, Murray, CA, Triaud, AHMJ, Gillen, E, Mortier, A, and Rackham, BV

Subjects
techniques: photometric, planets and satellites: detection, 13. Climate action, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Astrophysics::Galaxy Astrophysics, atmospheric effects
Abstract

We conducted a global analysis of the TRAPPIST Ultra-Cool Dwarf Transit Survey – a prototype of the SPECULOOS transit search conducted with the TRAPPIST-South robotic telescope in Chile from 2011 to 2017 – to estimate the occurrence rate of close-in planets such as TRAPPIST-1b orbiting ultra-cool dwarfs. For this purpose, the photometric data of 40 nearby ultra-cool dwarfs were reanalysed in a self-consistent and fully automated manner starting from the raw images. The pipeline developed specifically for this task generates differential light curves, removes non-planetary photometric features and stellar variability, and searches for transits. It identifies the transits of TRAPPIST-1b and TRAPPIST-1c without any human intervention. To test the pipeline and the potential output of similar surveys, we injected planetary transits into the light curves on a star-by-star basis and tested whether the pipeline is able to detect them. The achieved photometric precision enables us to identify Earth-sized planets orbiting ultra-cool dwarfs as validated by the injection tests. Our planet-injection simulation further suggests a lower limit of 10 per cent on the occurrence rate of planets similar to TRAPPIST-1b with a radius between 1 and 1.3 R⊕ and the orbital period between 1.4 and 1.8 d.

33. TOI-4010: A System of Three Large Short-Period Planets With a Massive Long-Period Companion

Author

Kunimoto, Michelle, Vanderburg, Andrew, Huang, Chelsea X., Davis, M. Ryleigh, Affer, Laura, Cameron, Andrew Collier, Charbonneau, David, Cosentino, Rosario, Damasso, Mario, Dumusque, Xavier, Fiorenzano, A. F. Martnez, Ghedina, Adriano, Haywood, R. D., Lienhard, Florian, López-Morales, Mercedes, Mayor, Michel, Pepe, Francesco, Pinamonti, Matteo, Poretti, Ennio, Maldonado, Jesús, Rice, Ken, Sozzetti, Alessandro, Wilson, Thomas G., Udry, Stéphane, Baptista, Jay, Barkaoui, Khalid, Becker, Juliette, Benni, Paul, Bieryla, Allyson, Bosch-Cabot, Pau, Ciardi, David R., Collins, Karen A., Collins, Kevin I., Evans, Elise, Dupuy, Trent J., Goliguzova, Maria V., Guerra, Pere, Kraus, Adam, Lissauer, Jack J., Huber, Daniel, Murgas, Felipe, Palle, Enric, Quinn, Samuel N., Safonov, Boris S., Schwarz, Richard P., Shporer, Avi, Stassun, Keivan G., Jenkins, Jon M., Latham, David W., Ricker, George R., Seager, Sara, Vanderspek, Roland, Winn, Joshua, Essack, Zahra, Lewis, Hannah M., Rose, Mark E., Kunimoto, M [0000-0001-9269-8060], Vanderburg, A [0000-0001-7246-5438], Huang, CX [0000-0003-0918-7484], Davis, MR [0000-0002-7451-4704], Affer, L [0000-0001-5600-3778], Cameron, AC [0000-0002-8863-7828], Charbonneau, D [0000-0002-9003-484X], Cosentino, R [0000-0003-1784-1431], Damasso, M [0000-0001-9984-4278], Dumusque, X [0000-0002-9332-2011], Fiorenzano, AFM [0000-0002-4272-4272], Ghedina, A [0000-0003-4702-5152], Haywood, RD [0000-0001-9140-3574], Lienhard, F [0000-0003-4047-0771], López-Morales, M [0000-0003-3204-8183], Mayor, M [0000-0002-9352-5935], Pepe, F [0000-0002-9815-773X], Pinamonti, M [0000-0002-4445-1845], Poretti, E [0000-0003-1200-0473], Maldonado, J [0000-0002-2218-5689], Rice, K [0000-0002-6379-9185], Sozzetti, A [0000-0002-7504-365X], Wilson, TG [0000-0001-8749-1962], Udry, S [0000-0001-7576-6236], Baptista, J [0000-0002-9306-1704], Barkaoui, K [0000-0003-1464-9276], Becker, J [0000-0002-7733-4522], Benni, P [0000-0001-6981-8722], Bieryla, A [0000-0001-6637-5401], Bosch-Cabot, P [0000-0002-1514-5558], Ciardi, DR [0000-0002-5741-3047], Collins, KA [0000-0001-6588-9574], Collins, KI [0000-0003-2781-3207], Dupuy, TJ [0000-0001-9823-1445], Goliguzova, MV [0000-0003-2228-7914], Guerra, P [0000-0002-4308-2339], Kraus, A [0000-0001-9811-568X], Lissauer, JJ [0000-0001-6513-1659], Huber, D [0000-0001-8832-4488], Murgas, F [0000-0001-9087-1245], Palle, E [0000-0003-0987-1593], Quinn, SN [0000-0002-8964-8377], Safonov, BS [0000-0003-1713-3208], Schwarz, RP [0000-0001-8227-1020], Shporer, A [0000-0002-1836-3120], Stassun, KG [0000-0002-3481-9052], Jenkins, JM [0000-0002-4715-9460], Latham, DW [0000-0001-9911-7388], Ricker, GR [0000-0003-2058-6662], Seager, S [0000-0002-6892-6948], Vanderspek, R [0000-0001-6763-6562], Winn, J [0000-0002-4265-047X], Essack, Z [0000-0002-2482-0180], Lewis, HM [0000-0002-7871-085X], Rose, ME [0000-0003-4724-745X], Apollo - University of Cambridge Repository, 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
MCC, Earth and Planetary Astrophysics (astro-ph.EP), Exoplanets, Exoplanet dynamics, FOS: Physical sciences, DAS, 5109 Space Sciences, Hot Neptunes, QB Astronomy, Transit photometry, Exoplanet systems, 51 Physical Sciences, Astrophysics - Earth and Planetary Astrophysics, QB
Abstract

We report the confirmation of three exoplanets transiting TOI-4010 (TIC-352682207), a metal-rich K dwarf observed by TESS in Sectors 24, 25, 52, and 58. We confirm these planets with HARPS-N radial velocity observations and measure their masses with 8 - 12% precision. TOI-4010 b is a sub-Neptune ($P = 1.3$ days, $R_{p} = 3.02_{-0.08}^{+0.08}~R_{\oplus}$, $M_{p} = 11.00_{-1.27}^{+1.29}~M_{\oplus}$) in the hot Neptune desert, and is one of the few such planets with known companions. Meanwhile, TOI-4010 c ($P = 5.4$ days, $R_{p} = 5.93_{-0.12}^{+0.11}~R_{\oplus}$, $M_{p} = 20.31_{-2.11}^{+2.13}~M_{\oplus}$) and TOI-4010 d ($P = 14.7$ days, $R_{p} = 6.18_{-0.14}^{+0.15}~R_{\oplus}$, $M_{p} = 38.15_{-3.22}^{+3.27}~M_{\oplus}$) are similarly-sized sub-Saturns on short-period orbits. Radial velocity observations also reveal a super-Jupiter-mass companion called TOI-4010 e in a long-period, eccentric orbit ($P \sim 762$ days and $e \sim 0.26$ based on available observations). TOI-4010 is one of the few systems with multiple short-period sub-Saturns to be discovered so far., Comment: 26 pages, 16 figures, published in AJ; (v3) added missing citation

Published
2023
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34. The EXPRES Stellar Signals Project II. State of the field in disentangling photospheric velocities

Author

Lily L. Zhao, Debra A. Fischer, Eric B. Ford, Alex Wise, Michaël Cretignier, Suzanne Aigrain, Oscar Barragan, Megan Bedell, Lars A. Buchhave, João D. Camacho, Heather M. Cegla, Jessi Cisewski-Kehe, Andrew Collier Cameron, Zoe L. de Beurs, Sally Dodson-Robinson, Xavier Dumusque, João P. Faria, Christian Gilbertson, Charlotte Haley, Justin Harrell, David W. Hogg, Parker Holzer, Ancy Anna John, Baptiste Klein, Marina Lafarga, Florian Lienhard, Vinesh Maguire-Rajpaul, Annelies Mortier, Belinda Nicholson, Michael L. Palumbo, Victor Ramirez Delgado, Christopher J. Shallue, Andrew Vanderburg, Pedro T. P. Viana, Jinglin Zhao, Norbert Zicher, Samuel H. C. Cabot, Gregory W. Henry, Rachael M. Roettenbacher, John M. Brewer, Joe Llama, Ryan R. Petersburg, Andrew E. Szymkowiak, Apollo-University Of Cambridge Repository, Zhao, LL [0000-0002-3852-3590], Fischer, DA [0000-0003-2221-0861], Ford, EB [0000-0001-6545-639X], Wise, A [0000-0002-5013-5769], Cretignier, M [0000-0002-2207-0750], Aigrain, S [0000-0003-1453-0574], Barragan, O [0000-0003-0563-0493], Bedell, M [0000-0001-9907-7742], Buchhave, LA [0000-0003-1605-5666], Camacho, JD [0000-0001-5121-5560], Cegla, HM [0000-0001-8934-7315], Cisewski-Kehe, J [0000-0002-9656-2272], Collier Cameron, A [0000-0002-8863-7828], De Beurs, ZL [0000-0002-7564-6047], Dodson-Robinson, S [0000-0002-8796-4974], Dumusque, X [0000-0002-9332-2011], Faria, JP [0000-0002-6728-244X], Gilbertson, C [0000-0002-1743-3684], Haley, C [0000-0003-3996-773X], Harrell, J [0000-0001-8936-6276], Hogg, DW [0000-0003-2866-9403], Holzer, P [0000-0001-8936-6276], John, AA [0000-0002-1715-6939], Klein, B [0000-0003-0637-5236], Lafarga, M [0000-0002-8815-9416], Lienhard, F [0000-0003-4047-0771], Maguire-Rajpaul, V [0000-0001-7576-6703], Mortier, A [0000-0001-7254-4363], Nicholson, B [0000-0003-1360-4404], Palumbo, ML [0000-0002-4677-8796], Ramirez Delgado, V [0000-0001-8183-459X], Shallue, CJ [0000-0002-7585-9974], Vanderburg, A [0000-0001-7246-5438], Viana, PTP [0000-0003-1572-8531], Zhao, J [0000-0001-5290-2952], Zicher, N [0000-0001-6143-2905], Cabot, SHC [0000-0001-9749-6150], Henry, GW [0000-0003-4155-8513], Roettenbacher, RM [0000-0002-9288-3482], Brewer, JM [0000-0002-9873-1471], Llama, J [0000-0003-4450-0368], Petersburg, RR [0000-0003-2168-0191], Szymkowiak, AE [0000-0002-4974-687X], Apollo - University of Cambridge Repository, Zhao, Lily L. [0000-0002-3852-3590], Fischer, Debra A. [0000-0003-2221-0861], Ford, Eric B. [0000-0001-6545-639X], Wise, Alex [0000-0002-5013-5769], Cretignier, Michaël [0000-0002-2207-0750], Aigrain, Suzanne [0000-0003-1453-0574], Barragan, Oscar [0000-0003-0563-0493], Bedell, Megan [0000-0001-9907-7742], Buchhave, Lars A. [0000-0003-1605-5666], Camacho, João D. [0000-0001-5121-5560], Cegla, Heather M. [0000-0001-8934-7315], Cisewski-Kehe, Jessi [0000-0002-9656-2272], Collier Cameron, Andrew [0000-0002-8863-7828], de Beurs, Zoe L. [0000-0002-7564-6047], Dodson-Robinson, Sally [0000-0002-8796-4974], Dumusque, Xavier [0000-0002-9332-2011], Faria, João P. [0000-0002-6728-244X], Gilbertson, Christian [0000-0002-1743-3684], Haley, Charlotte [0000-0003-3996-773X], Harrell, Justin [0000-0001-8936-6276], Hogg, David W. [0000-0003-2866-9403], Holzer, Parker [0000-0001-8936-6276], John, Ancy Anna [0000-0002-1715-6939], Klein, Baptiste [0000-0003-0637-5236], Lafarga, Marina [0000-0002-8815-9416], Lienhard, Florian [0000-0003-4047-0771], Maguire-Rajpaul, Vinesh [0000-0001-7576-6703], Mortier, Annelies [0000-0001-7254-4363], Nicholson, Belinda [0000-0003-1360-4404], Palumbo, Michael L., III [0000-0002-4677-8796], Ramirez Delgado, Victor [0000-0001-8183-459X], Shallue, Christopher J. [0000-0002-7585-9974], Vanderburg, Andrew [0000-0001-7246-5438], Viana, Pedro T. P. [0000-0003-1572-8531], Zhao, Jinglin [0000-0001-5290-2952], Zicher, Norbert [0000-0001-6143-2905], Cabot, Samuel H. C. [0000-0001-9749-6150], Henry, Gregory W. [0000-0003-4155-8513], Roettenbacher, Rachael M. [0000-0002-9288-3482], Brewer, John M. [0000-0002-9873-1471], Llama, Joe [0000-0003-4450-0368], Petersburg, Ryan R. [0000-0003-2168-0191], Szymkowiak, Andrew E. [0000-0002-4974-687X], 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
Radial velocity, astro-ph.SR, FOS: Physical sciences, QB Astronomy, Exoplanet detection methods, Astrophysics::Solar and Stellar Astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), Solar and Stellar Astrophysics (astro-ph.SR), QC, Stellar activity, QB, Earth and Planetary Astrophysics (astro-ph.EP), MCC, Spectrometers, The Solar System, Exoplanets, and Astrobiology, Astronomy and Astrophysics, 3rd-DAS, QC Physics, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, astro-ph.EP, Planet hosting stars, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics, astro-ph.IM, Astrophysics - Earth and Planetary Astrophysics
Abstract

Measured spectral shifts due to intrinsic stellar variability (e.g., pulsations, granulation) and activity (e.g., spots, plages) are the largest source of error for extreme precision radial velocity (EPRV) exoplanet detection. Several methods are designed to disentangle stellar signals from true center-of-mass shifts due to planets. The EXPRES Stellar Signals Project (ESSP) presents a self-consistent comparison of 22 different methods tested on the same extreme-precision spectroscopic data from EXPRES. Methods derived new activity indicators, constructed models for mapping an indicator to the needed RV correction, or separated out shape- and shift-driven RV components. Since no ground truth is known when using real data, relative method performance is assessed using the total and nightly scatter of returned RVs and agreement between the results of different methods. Nearly all submitted methods return a lower RV RMS than classic linear decorrelation, but no method is yet consistently reducing the RV RMS to sub-meter-per-second levels. There is a concerning lack of agreement between the RVs returned by different methods. These results suggest that continued progress in this field necessitates increased interpretability of methods, high-cadence data to capture stellar signals at all timescales, and continued tests like the ESSP using consistent data sets with more advanced metrics for method performance. Future comparisons should make use of various well-characterized data sets -- such as solar data or data with known injected planetary and/or stellar signals -- to better understand method performance and whether planetary signals are preserved., 33 pages (+12 pages of Appendix), 10 figures, 8 tables, accepted for publication in AJ

Published
2022

35. A pair of TESS planets spanning the radius valley around the nearby mid-M dwarf LTT 3780

Author

Andrew W. Mann, Dimitar Sasselov, Jon M. Jenkins, Charles A. Beichman, Steve B. Howell, F. Lienhard, David Charbonneau, Joseph E. Rodriguez, Giampaolo Piotto, Ken Rice, Avet Harutyunyan, Matteo Pinamonti, Eric D. Lopez, Laura Kreidberg, David W. Latham, Xavier Dumusque, Mercedes Lopez-Morales, Michel Mayor, George R. Ricker, Nicola Astudillo-Defru, Jack J. Lissauer, Douglas A. Caldwell, Kevin I. Collins, A. Magazzu, Joseph D. Twicken, Joshua E. Schlieder, Andrew Collier Cameron, David F. Phillips, Xavier Delfosse, Joshua N. Winn, Dennis M. Conti, M. Stalport, Rosario Cosentino, Sara Seager, Rodrigo F. Díaz, Annelies Mortier, Sébastien Lépine, Patricia T. Boyd, Rachel A. Matson, John F. Kielkopf, David R. Ciardi, Stéphane Udry, Cesar Briceno, Thierry Forveille, Nicholas M. Law, Samuel N. Quinn, Adriano Ghedina, Lars A. Buchhave, Ennio Poretti, Nuno C. Santos, Karen A. Collins, René Doyon, Xavier Bonfils, Emilio Molinari, Aldo F. M. Fiorenzano, Jason D. Eastman, Eric L. N. Jensen, Étienne Artigau, Alessandro Sozzetti, Jonathan Irwin, Michael Vezie, Benjamin V. Rackham, Pedro Figueira, Mario Damasso, L. Mignon, Damien Ségransan, Francesco Pepe, Claudio Melo, Carl Ziegler, Jennifer G. Winters, Elisabeth Matthews, José Renan de Medeiros, Luca Di Fabrizio, Giuseppina Micela, Christophe Lovis, Ian J. M. Crossfield, François Bouchy, Christopher J. Burke, J. M. Almenara, Roland Vanderspek, John Asher Johnson, Ryan Cloutier, Peter Tenenbaum, Christopher A. Watson, Courtney D. Dressing, Robert Massey, Erica J. Gonzales, Science & Technology Facilities Council, University of St Andrews. School of Physics and Astronomy, University of St Andrews. St Andrews Centre for Exoplanet Science, Harvard-Smithsonian Center for Astrophysics (CfA), Smithsonian Institution-Harvard University [Cambridge], 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), Cloutier, R [0000-0001-5383-9393], Eastman, JD [0000-0003-3773-5142], Rodriguez, JE [0000-0001-8812-0565], Mortier, A [0000-0001-7254-4363], Pinamonti, M [0000-0002-4445-1845], Lienhard, F [0000-0003-4047-0771], Latham, DW [0000-0001-9911-7388], Collins, KA [0000-0001-6588-9574], Massey, R [0000-0001-8879-7138], Winters, JG [0000-0001-6031-9513], Charbonneau, D [0000-0002-9003-484X], Ziegler, C [0000-0002-0619-7639], Matthews, E [0000-0003-0593-1560], Kreidberg, L [0000-0003-0514-1147], Quinn, SN [0000-0002-8964-8377], Ricker, G [0000-0003-2058-6662], Vanderspek, R [0000-0001-6763-6562], Seager, S [0000-0002-6892-6948], Winn, J [0000-0002-4265-047X], Jenkins, JM [0000-0002-4715-9460], Udry, S [0000-0001-7576-6236], Twicken, JD [0000-0002-6778-7552], Tenenbaum, P [0000-0002-1949-4720], Sozzetti, A [0000-0002-7504-365X], Ségransan, D [0000-0003-2355-8034], Schlieder, JE [0000-0001-5347-7062], Sasselov, D [0000-0001-7014-1771], Santos, NC [0000-0003-4422-2919], Rackham, BV [0000-0002-3627-1676], Poretti, E [0000-0003-1200-0473], Piotto, G [0000-0002-9937-6387], Molinari, E [0000-0002-1742-7735], Micela, G [0000-0002-9900-4751], De Medeiros, JR [0000-0001-8218-1586], Matson, RA [0000-0001-7233-7508], Mann, AW [0000-0003-3654-1602], Magazzú, A [0000-0003-1259-4371], López-Morales, M [0000-0003-3204-8183], Lissauer, JJ [0000-0001-6513-1659], Law, N [0000-0001-9380-6457], Kielkopf, JF [0000-0003-0497-2651], Jensen, ELN [0000-0002-4625-7333], Howell, SB [0000-0002-2532-2853], Ghedina, A [0000-0003-4702-5152], Forveille, T [0000-0003-0536-4607], Figueira, P [0000-0001-8504-283X], Dumusque, X [0000-0002-9332-2011], Dressing, CD [0000-0001-8189-0233], Díaz, RF [0000-0001-9289-5160], Conti, DM [0000-0003-2239-0567], Collins, KI [0000-0003-2781-3207], Ciardi, D [0000-0002-5741-3047], Caldwell, DA [0000-0003-1963-9616], Burke, C [0000-0002-7754-9486], Buchhave, L [0000-0003-1605-5666], Boyd, P [0000-0003-0442-4284], and Apollo - University of Cambridge Repository

Subjects
Radial velocity, 010504 meteorology & atmospheric sciences, Stellar mass, NDAS, FOS: Physical sciences, Astrophysics, M dwarf stars, 01 natural sciences, Planet, 0103 physical sciences, QB Astronomy, Spectroscopy, 010303 astronomy & astrophysics, Exoplanet systems, QC, 0105 earth and related environmental sciences, QB, Physics, Earth and Planetary Astrophysics (astro-ph.EP), Astronomy and Astrophysics, Radius, Planetary system, Photoevaporation, Stars, QC Physics, Space and Planetary Science, astro-ph.EP, Transit photometry, Low Mass, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Earth and Planetary Astrophysics
Abstract

We present the confirmation of two new planets transiting the nearby mid-M dwarf LTT 3780 (TIC 36724087, TOI-732, $V=13.07$, $K_s=8.204$, $R_s$=0.374 R$_{\odot}$, $M_s$=0.401 M$_{\odot}$, d=22 pc). The two planet candidates are identified in a single TESS sector and are validated with reconnaissance spectroscopy, ground-based photometric follow-up, and high-resolution imaging. With measured orbital periods of $P_b=0.77$ days, $P_c=12.25$ days and sizes $r_{p,b}=1.33\pm 0.07$ R$_{\oplus}$, $r_{p,c}=2.30\pm 0.16$ R$_{\oplus}$, the two planets span the radius valley in period-radius space around low mass stars thus making the system a laboratory to test competing theories of the emergence of the radius valley in that stellar mass regime. By combining 63 precise radial-velocity measurements from HARPS and HARPS-N, we measure planet masses of $m_{p,b}=2.62^{+0.48}_{-0.46}$ M$_{\oplus}$ and $m_{p,c}=8.6^{+1.6}_{-1.3}$ M$_{\oplus}$, which indicates that LTT 3780b has a bulk composition consistent with being Earth-like, while LTT 3780c likely hosts an extended H/He envelope. We show that the recovered planetary masses are consistent with predictions from both photoevaporation and from core-powered mass loss models. The brightness and small size of LTT 3780, along with the measured planetary parameters, render LTT 3780b and c as accessible targets for atmospheric characterization of planets within the same planetary system and spanning the radius valley., Comment: Accepted to AJ. 8 figures, 6 tables. CSV file of the RV measurements (i.e. Table 2) are included in the source code

Published
2020

36. Endurance training affects myosin heavy chain phenotype in regenerating fast-twitch muscle.

Author

Bigard XA, Janmot C, Merino D, Lienhard F, Guezennec YC, and D'Albis A

Subjects
Animals, Immunohistochemistry, Male, Rats, Rats, Wistar, Muscle Fibers, Fast-Twitch metabolism, Myosin Heavy Chains metabolism, Physical Conditioning, Animal physiology, Regeneration physiology
Abstract

The aim of this study was to analyze the effects of treadmill training (2 h/day, 5 days/wk, 30 m/min, 7% grade for 5 wk) on the expression of myosin heavy chain (MHC) isoforms during and after regeneration of a fast-twitch white muscle [extensor digitorum longus (EDL)]. Male Wistar rats were randomly assigned to a sedentary (n = 10) or an endurance-trained (ET; n = 10) group. EDL muscle degeneration and regeneration were induced by two subcutaneous injections of a snake toxin. Five days after induction of muscle injury, animals were trained over a 5-wk period. It was verified that approximately 40 days after venom treatment, central nuclei were present in the treated EDL muscles from sedentary and ET rats. The changes in the expression of MHCs in EDL muscles were detected by using a combination of biochemical and immunocytochemical approaches. Compared with contralateral nondegenerated muscles, relative concentrations of types I, IIa, and IIx MHC isoforms in ET rats were greater in regenerated EDL muscles (146%, P < 0.05; 76%, P < 0.01; 87%, P < 0.01, respectively). Their elevation corresponded to a decrease in the relative concentration of type IIb MHC (-36%, P < 0.01). Although type I accounted for only 3.2% of total myosin in regenerated muscles from the ET group, the cytochemical analysis showed that the proportion of positive staining with the slow MHC antibody was markedly greater in regenerated muscles than in contralateral ones. Collectively, these results demonstrate that the regenerated EDL muscle is sensitive to endurance training and suggest that the training-induced shift in MHC isoforms observed in these muscles resulted from an additive effect of regeneration and repeated exercise.

Published
1996
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37. Effects of chronic low frequency stimulation on structural and metabolic properties of hindlimb suspended rat soleus muscle.

Author

Canton F, Bigard AX, Merino D, Lienhard F, and Guezennec CY

Subjects
Animals, Atrophy, Body Weight, Capillary Action, Cell Size physiology, Citrate (si)-Synthase metabolism, Hindlimb physiology, Histocytochemistry, Immobilization physiology, Immunohistochemistry, Male, Muscle Fibers, Skeletal pathology, Muscle Proteins metabolism, Myosins metabolism, Organ Size, Rats, Rats, Wistar, Time Factors, Electric Stimulation, Muscle, Skeletal metabolism, Muscle, Skeletal pathology
Abstract

The use of chronic low frequency stimulations (CLFS, 10 Hz bipolar current 8 h.day-1) as a countermeasure against unweighting-induced muscle alterations was investigated in rat soleus muscle during 21 days of hindlimb suspension (HS). It was shown that CLFS was able to minimize the soleus muscle atrophy induced by suspension (-29% in stimulated muscles compared to -56% in the non-stimulated soleus muscle). In parallel, CLFS partly prevented the HS-induced decreases in the cross-sectional area of type I fibres and in the total and myofibril protein contents. Stimulation at low frequency reduced the increase in the fast-myosin expression recorded with unweighting. Moreover, the HS-induced increase in glycolytic capacity was counteracted to a considerable extent by CLFS. In conclusion, the results of this study showed that CLFS can only partly prevent the HS-induced modifications in the soleus muscle. However, the limited effectiveness of CLFS to prevent muscle atrophy emphasized the critical role of reduced load bearing in the induction of soleus muscle atrophy.

Published
1995
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38. Structural and biochemical properties of the rat myocardium after 21 days of head-down suspension.

Author

Bigard AX, Serrurier B, Mérino D, Lienhard F, and Guezennec CY

Subjects
Animals, Heart Ventricles enzymology, Heart Ventricles pathology, L-Lactate Dehydrogenase metabolism, Male, Myocardium enzymology, Rats, Rats, Wistar, Time Factors, Myocardium pathology, Myosins metabolism, Posture
Abstract

The effects of 21 d of head-down suspension on the biochemical and structural properties of the myocardium were determined in male rats (HDS, n = 10), and compared with control non-suspended animals (C, n = 10). HDS rats were prepared using Morey's tail-suspension model, and maintained at 45 degrees tilt. At the end of the conditioning period, hearts were excised and dissected into right (RV) and left plus intraventricular septum (LV). We observed that HDS rats had lower LV- and RV-absolute weights than C animals (-8.5%, p < 0.05, and -12%, p < 0.05, respectively). The relative ventricle weights (ventricle weight/body weight, mg.g-1) were unaffected by HDS. Native myosin isoform analysis revealed that HDS did not alter myosin expression in both LV and RV. The capillary bed, examined using histochemical methods, was found to be unaffected by HDS. A significant decrease in the lactate dehydrogenase activity was detected in LV after 21 d of HDS (-16%, p < 0.05). Collectively, these results suggest that the early neurohumoral changes occurring in response to HDS-induced hemodynamic overload are sufficient to prevent any alteration in the biochemical and structural properties of the myocardial tissue.

Published
1994

39. Effects of surface electrostimulation on the structure and metabolic properties in monkey skeletal muscle.

Author

Bigard AX, Lienhard F, Merino D, Serrurier B, and Guezennec CY

Subjects
Adaptation, Physiological, Analysis of Variance, Animals, Chi-Square Distribution, Citrate (si)-Synthase metabolism, Dihydrolipoamide Dehydrogenase metabolism, Histocytochemistry, Macaca mulatta, Male, Muscles blood supply, Physical Conditioning, Animal, Muscle Contraction physiology, Muscles anatomy & histology, Muscles enzymology, Transcutaneous Electric Nerve Stimulation
Abstract

Adaptative changes in skeletal muscle following surface electrical stimulation (SES) were investigated in rhesus monkeys. SES was performed on the triceps brachialis muscle (TB) according to an intermittent pattern. The procedure was carried out for 3 wk, using a current with a medium frequency of 60 Hz normally observed in fast motor axons. The histochemical assays performed on biopsies taken from proximal and distal parts of the TB muscle, before and after the SES program, showed that the distribution of fibers typed by ATPase was unaffected. On the other hand, SES led to an overall increase in the mean fiber cross-sectional area (FCSA); P < 0.01 (+13.7%, NS, in proximal portion, vs +31%, P < 0.01 in distal portion). This increase in size occurred in all fiber types. SES was shown to induce an overall increase in capillary to fiber ratio (C/F; +11.06%, NS, in proximal portion, vs +25.93%, P < 0.05 in distal portion). The number of capillaries surrounding fiber Type II (CAFII) was significantly increased by SES (P < 0.05): +3.21%, NS, in proximal portion, versus +21.47%, P < 0.05 in distal portion. Moreover, the number of capillaries surrounding fiber Type I (CAFI) was statistically unaffected by SES. These results suggest that a stimulation of capillary growth may occur following SES-training. Citrate synthase activity was significantly increased after SES. This enhancement in oxidative potential was shown to occur in all fiber types (NADH-diaphorase staining).(ABSTRACT TRUNCATED AT 250 WORDS)

Published
1993

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