Astronomy and Astrophysics, volume 602A, 107-107 (2017/6-1)
The GAPS Programme with HARPS-N at TNG. XIV. Investigating giant planet migration history via improved eccentricity and mass determination for 231 transiting planets.
BONOMO A.S., DESIDERA S., BENATTI S., BORSA F., CRESPI S., DAMASSO M., LANZA A.F., SOZZETTI A., LODATO G., MARZARI F., BOCCATO C., CLAUDI R.U., COSENTINO R., COVINO E., GRATTON R., MAGGIO A., MICELA G., MOLINARI E., PAGANO I., PIOTTO G., PORETTI E., SMAREGLIA R., AFFER L., BIAZZO K., BIGNAMINI A., ESPOSITO M., GIACOBBE P., HEBRARD G., MALAVOLTA L., MALDONADO J., MANCINI L., MARTINEZ FIORENZANO A., MASIERO S., NASCIMBENI V., PEDANI M., RAINER M. and SCANDARIATO G.
Abstract (from CDS):
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<0.05au 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.
© ESO, 2017
planetary systems - techniques: radial velocities - stars: fundamental parameters - planet-star interactions - planet-star interactions
VizieR on-line data:
<Available at CDS (J/A+A/602/A107): table1.dat table2.dat table5.dat table6.dat table7.dat table8.dat table9.dat refs.dat>
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