Volume 602, June 2017
|Number of page(s)||16|
|Section||Planets and planetary systems|
|Published online||23 June 2017|
The GAPS Programme with HARPS-N at TNG
XIV. Investigating giant planet migration history via improved eccentricity and mass determination for 231 transiting planets⋆
1 INAF–Osservatorio Astrofisico di Torino, via Osservatorio 20, 10025 Pino Torinese, Italy
2 INAF–Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio 5, 35122 Padova, Italy
3 INAF–Osservatorio Astronomico di Brera, via E. Bianchi 46, 23807 Merate (LC), Italy
4 Dipartimento di Fisica, Università Degli Studi di Milano, via Celoria 16, 20133 Milano, Italy
5 INAF–Osservatorio Astrofisico di Catania, via S. Sofia 78, 95123 Catania, Italy
6 Dipartimento di Fisica e Astronomia Galileo Galilei–Università di Padova, Vicolo dell Osservatorio 3, 35122 Padova, Italy
7 Fundación Galileo Galilei–INAF, Rambla José Ana Fernandez Pérez 7, 38712 Breña Baja, TF, Spain
8 INAF–Osservatorio Astronomico di Capodimonte, Salita Moiariello 16, 80131 Napoli, Italy
9 INAF–Osservatorio Astronomico di Palermo, Piazza del Parlamento, 1, 90134 Palermo, Italy
10 INAF–Osservatorio Astronomico di Trieste, via Tiepolo 11, 34143 Trieste, Italy
11 Institut d’Astrophysique de Paris, UMR 7095 CNRS, Université Pierre & Marie Curie, 98bis boulevard Arago, 75014 Paris, France
12 Observatoire de Haute-Provence, Université Aix-Marseille & CNRS, 04870 St. Michel l’ Observatoire, France
13 Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany
14 GAL Hassin, Centro Internazionale per le Scienze Astronomiche, 90010 Isnello, Italy
Received: 11 October 2016
Accepted: 1 March 2017
We carried out a Bayesian homogeneous determination of the orbital parameters of 231 transiting giant planets (TGPs) that are alone or have distant companions; we employed differential evolution Markov chain Monte Carlo methods to analyse radial-velocity (RV) data from the literature and 782 new high-accuracy RVs obtained with the HARPS-N spectrograph for 45 systems over ~3 years. Our work yields the largest sample of systems with a transiting giant exoplanet and coherently determined orbital, planetary, and stellar parameters. We found that the orbital parameters of TGPs in non-compact planetary systems are clearly shaped by tides raised by their host stars. Indeed, the most eccentric planets have relatively large orbital separations and/or high mass ratios, as expected from the equilibrium tide theory. This feature would be the outcome of planetary migration from highly eccentric orbits excited by planet-planet scattering, Kozai-Lidov perturbations, or secular chaos. The distribution of α = a/aR, where a and aR are the semi-major axis and the Roche limit, for well-determined circular orbits peaks at 2.5; this agrees with expectations from the high-eccentricity migration (HEM), although it might not be limited to this migration scenario. The few planets of our sample with circular orbits and α> 5 values may have migrated through disc-planet interactions instead of HEM. By comparing circularisation times with stellar ages, we found that hot Jupiters with a< 0.05 au have modified tidal quality factors 105 ≲ Q'p ≲ 109, and that stellar Q's ≳ 106 - 107 are required to explain the presence of eccentric planets at the same orbital distance. As aby-product of our analysis, we detected a non-zero eccentricity e = 0.104-0.018+0.021 for HAT-P-29; we determined that five planets that were previously regarded to be eccentric or to have hints of non-zero eccentricity, namely CoRoT-2b, CoRoT-23b, TrES-3b, HAT-P-23b, and WASP-54b, have circular orbits or undetermined eccentricities; we unveiled curvatures caused by distant companions in the RV time series of HAT-P-2, HAT-P-22, and HAT-P-29; we significantly improved the orbital parameters of the long-period planet HAT-P-17c; and we revised the planetary parameters of CoRoT-1b, which turned out to be considerably more inflated than previously found.
Key words: planetary systems / techniques: radial velocities / stars: fundamental parameters / planet-star interactions
Full Tables 1, 2, 5–9 are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (18.104.22.168) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/602/A107
© ESO, 2017
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