Improved parameters of seven Kepler giant companions characterized with SOPHIE and HARPS-N

Abstract

Radial-velocity observations of Kepler candidates obtained with the SOPHIE and HARPS-N spectrographs have permitted unveiling the nature of the five giant planets Kepler-41b, Kepler-43b, Kepler-44b, Kepler-74b, and Kepler-75b, the massive companion Kepler-39b, and the brown dwarf KOI-205b. These companions were previously characterized with long-cadence (LC) Kepler data. Here we aim at refining the parameters of these transiting systems by i) modelling the published radial velocities (RV) and Kepler short-cadence (SC) data that provide a much better sampling of the transits, ii) performing new spectral analyses of the SOPHIE and ESPaDOnS spectra, and iii) improving stellar rotation periods hence stellar age estimates through gyrochronology, when possible. Posterior distributions of the system parameters were derived with a differential evolution Markov chain Monte Carlo approach. Our main results are as follows: a) Kepler-41b is significantly larger and less dense than previously found because a lower orbital inclination is favoured by SC data. This also affects the determination of the geometric albedo that is lower than previously derived: Ag < 0.135; b) Kepler-44b is moderately smaller and denser than reported in the discovery paper; c) good agreement was achieved with published Kepler-43, Kepler-75, and KOI-205 system parameters, although the host stars Kepler-75 and KOI-205 were found to be slightly richer in metals and hotter, respectively; d) the previously reported non-zero eccentricities of Kepler-39b and Kepler-74b might be spurious. If their orbits were circular, the two companions would be smaller and denser than in the eccentric case. The radius of Kepler-39b is still larger than predicted by theoretical isochrones. Its parent star is hotter and richer in metals than previously determined. [ABRIDGED]

17 pages, 9 figures, accepted for publication in Astronomy and Astrophysics

References in corpus (11)

• The generalised Lomb-Scargle periodogram. A new formalism for the floating-mean and Keplerian periodograms
• Improved Age Estimation for Solar-Type Dwarfs Using Activity-Rotation Diagnostics
• Achieving better than 1 minute accuracy in the Heliocentric and Barycentric Julian Dates
• EXOFAST: A fast exoplanetary fitting suite in IDL
• The effect of red noise on planetary transit detection
• Improving Stellar and Planetary Parameters of Transiting Planet Systems: The Case of TrES-2
• SOPHIE velocimetry of Kepler transit candidates VII. A false-positive rate of 35% for Kepler close-in giant exoplanet candidates
• Observability of the General Relativistic Precession of Periastra in Exoplanets
• Optical Albedo Theory of Strongly-Irradiated Giant Planets: The Case of HD 209458b
• SOPHIE velocimetry of Kepler transit candidates. VIII. KOI-205 b: a brown-dwarf companion to a K-type dwarf
• Transit Light Curves with Finite Integration Time: Fisher Information Analysis

Cited by in corpus (26)

• A giant impact as the likely origin of different twins in the Kepler-107 exoplanet system
• Exoplanet atmospheres with GIANO II. Detection of molecular absorption in the dayside spectrum of HD 102195b
• The Densities of Planets in Multiple Stellar Systems
• Two intermediate-mass transiting brown dwarfs from the TESS mission
• Populating the brown dwarf and stellar boundary: Five stars with transiting companions near the hydrogen-burning mass limit
• TOI-811b and TOI-852b: New transiting brown dwarfs with similar masses and very different radii and ages from the TESS mission
• A sub-Neptune and a non-transiting Neptune-mass companion unveiled by ESPRESSO around the bright late-F dwarf HD 5278 (TOI-130)
• The GAPS Programme at TNG LV. Multiple molecular species in the atmosphere of HAT-P-11 b and review of the HAT-P-11 planetary system
• NLTT5306B: an inflated, weakly irradiated brown dwarf
• Three new brown dwarfs and a massive hot Jupiter revealed by TESS around early-type stars
• Improved radius determinations for the transiting brown dwarf population in the era of Gaia and TESS
• On a Possible Solution to the Tidal Realignment Problem for Hot Jupiters
• TOI 694 b and TIC 220568520 b: Two Low-Mass Companions Near the Hydrogen Burning Mass Limit Orbiting Sun-like Stars
• Determining Exoplanetary Oblateness Using Transit Depth Variations
• HIP 33609 b: An Eccentric Brown Dwarf Transiting a V=7.3 Rapidly Rotating B-Star
• The GAPS Programme at TNG XL: A puffy and warm Neptune-sized planet and an outer Neptune-mass candidate orbiting the solar-type star TOI-1422
• A warm super-Neptune around the G-dwarf star TOI-1710 revealed with TESS, SOPHIE and HARPS-N
• Tidal Response and Shape of Hot Jupiters
• Hundreds of TESS exoplanets might be larger than we thought
• Minimum Orbital Periods of H-Rich Bodies
• Observations of scattered light from exoplanet atmospheres
• Kepler-102: Masses and Compositions for a Super-Earth and Sub-Neptune Orbiting an Active Star
• Low-mass and sub-stellar eclipsing binaries in stellar clusters
• SIOUX project: a simultaneous multiband camera for exoplanet atmospheres studies
• The GAPS programme at TNG LXXI. A sub-Neptune suitable for atmospheric characterization in a multiplanet and mutually inclined system orbiting the bright K dwarf TOI-5789 (HIP 99452)
• Evidence of Radius Inflation Based on 50 Transiting Brown Dwarfs and Low-mass Stellar Companions