Tidal Dissipation In Rotating Low Mass Stars: Implications For The Orbital Evolution Of Close In Planets
Abstract
Close-in planets represent a large fraction of the population of confirmed exoplanets. To understand the dynamical evolution of these planets, star-planet interactions must be taken into account. In particular, the dependence of the tidal interactions on the structural parameters of the star, its rotation, and its metallicity should be treated in the models. We quantify how the tidal dissipation in the convective envelope of rotating low-mass stars evolves in time. We also investigate the possible consequences of this evolution on planetary orbital evolution. In Gallet et al. (2017) and Bolmont et al. (2017) we generalized the work of Bolmont & Mathis (2016) by following the orbital evolution of close-in planets using the new tidal dissipation predictions for advanced phases of stellar evolution and non-solar metallicity. We find that during the pre-main sequence the evolution of tidal dissipation is controlled by the evolution of the internal structure of the star through the stellar contraction. On the main-sequence tidal dissipation is strongly driven by the evolution of the surface rotation that is impacted by magnetized stellar winds braking. Finally, during the more evolved phases, the tidal dissipation sharply decreases as radiative core retreats in mass and radius towards the red-giant branch. Using an orbital evolution model, we also show that changing the metallicity leads to diUerent orbital evolutions (e.g., planets migrate farther out from an initially fast rotating metal rich star). By using this model, we qualitatively reproduced the observational trends of the population of hot Jupiters with the metallicity of their host stars. However, more work still remain to be do so as to be able to quantitatively fit our results to the observations.
- Publication:
-
EWASS Special Session 4 (2017): Star-planet interactions (EWASS-SS4-2017)
- Pub Date:
- October 2017
- DOI:
- 10.5281/zenodo.1059407
- Bibcode:
- 2017ewas.confE..10G
- Keywords:
-
- hydrodynamics;
- waves;
- planet-star interactions;
- planet-star interactions;
- stars: evolution;
- stars: rotation;
- stars: abundances;
- stars: solar-type;
- Zenodo community ewass-ss4-2017