Tidal evolution of close-in exoplanets and host stars

• Published in: Monthly notices of the Royal Astronomical Society Vol. 523; no. 4; pp. 5220 - 5229
• Main Authors: Ferraz-Mello, S, Beaugé, C
• Format: Journal Article
• Language: English
• Published: Oxford University Press 22.06.2023
• Subjects: stars: rotation; planet–star interactions
• ISSN: 0035-8711; 1365-2966
• DOI: 10.1093/mnras/stad1777

ABSTRACT The evolution of exoplanetary systems with a close-in planet is ruled by the tides mutually raised on the two bodies and by the magnetic braking of the host star. This paper deals with consequences of this evolution and some features that can be observed in the distribution of the systems' two main periods: the orbital period and the stars rotational period. The results of the simulations are compared to plots showing both periods as determined from the light curves of a large number of Kepler objects of interest. These plots show important irregularities as a dearth of systems in some regions and accumulations of hot Jupiters in others. It is shown that the accumulation of short-period hot Jupiters around stars with rotation periods close to 25 d results from the evolution of the systems under the joint action of tides and braking, and requires a relaxation factor for Solar-type stars of around $10 \, \mathrm{ s}^{-1}$.