The GAPS Programme with HARPSN at TNG . XIV. Investigating giant planet migration history via improved eccentricity and mass determination for 231 transiting planets
Abstract
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 radialvelocity (RV) data from the literature and 782 new highaccuracy RVs obtained with the HARPSN 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 noncompact 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 planetplanet scattering, KozaiLidov perturbations, or secular chaos. The distribution of α = a/a_{R}, where a and a_{R} are the semimajor axis and the Roche limit, for welldetermined circular orbits peaks at 2.5; this agrees with expectations from the higheccentricity 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 discplanet 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 10^{5} ≲ Q'_{p} ≲ 10^{9}, and that stellar Q'_{s} ≳ 10^{6}  10^{7} are required to explain the presence of eccentric planets at the same orbital distance. As abyproduct of our analysis, we detected a nonzero eccentricity e = 0.104_{0.018}^{+0.021} for HATP29; we determined that five planets that were previously regarded to be eccentric or to have hints of nonzero eccentricity, namely CoRoT2b, CoRoT23b, TrES3b, HATP23b, and WASP54b, have circular orbits or undetermined eccentricities; we unveiled curvatures caused by distant companions in the RV time series of HATP2, HATP22, and HATP29; we significantly improved the orbital parameters of the longperiod planet HATP17c; and we revised the planetary parameters of CoRoT1b, which turned out to be considerably more inflated than previously found.
Full Tables 1, 2, 59 are only available at the CDS via anonymous ftp to http://cdsarc.ustrasbg.fr (http://130.79.128.5) or via http://cdsarc.ustrasbg.fr/vizbin/qcat?J/A+A/602/A107
 Publication:

Astronomy and Astrophysics
 Pub Date:
 June 2017
 DOI:
 10.1051/00046361/201629882
 arXiv:
 arXiv:1704.00373
 Bibcode:
 2017A&A...602A.107B
 Keywords:

 planetary systems;
 techniques: radial velocities;
 stars: fundamental parameters;
 planetstar interactions;
 Astrophysics  Earth and Planetary Astrophysics;
 Astrophysics  Solar and Stellar Astrophysics
 EPrint:
 44 pages (16 pages of main text and figures), 11 figures, 5 longtables, published in Astronomy and Astrophysics, Volume 602, A107 (2017). Tables with new HARPSN and TRES radialvelocity data (Tables 1 and 2), stellar parameters (Table 7), orbital parameters and RV jitter (Table 8), and planet physical parameters (Table 9) are available as ancillary files (sidebar on the right)