The Rate of Planet-star Coalescences Due to Tides and Stellar Evolution
arXiv:1909.01719 · doi:10.1093/mnras/stz2783
Abstract
Orbits of close-in planets can shrink significantly due to dissipation of tidal energy in a host star. This process can result in star-planet coalescence within the Galactic lifetime. In some cases, such events can be accompanied by an optical or/and UV/X-ray transient. Potentially, these outbursts can be observed in near future with new facilities such as LSST from distances about few Mpc. We use a population synthesis model to study this process and derive the rate of star-planet mergers of different types. Mostly, planets are absorbed by red giants. However, these events, happening with the rate about 3 per year, mostly do not produce detectable transients. The rate of mergers with main sequence stars depends on the effectiveness of tidal dissipation; for reasonable values of stellar tidal quality factor, such events happen in a Milky Way-like galaxy approximately once in 70 yrs or more rarely. This rate is dominated by planets with low masses. Such events do not produce bright transients having maximum luminosities erg s. Brighter events, related to massive planets, with maximum luminosity --erg s, have the rate nearly five times smaller.
16 pages, 11 figures, 2 tables, accepted to MNRAS; corrected references
References in corpus (16)
- The Transiting Exoplanet Survey Satellite
- Seven temperate terrestrial planets around the nearby ultracool dwarf star TRAPPIST-1
- Improving PARSEC models for very low mass stars
- Tidal dissipation in stars and giant planets
- Tidal Evolution of Close-in Extra-Solar Planets
- The population of long-period transiting exoplanets
- Formation and composition of planets around very low mass stars
- Tidal dissipation in rotating low-mass stars and implications for the orbital evolution of close-in planets I. From the PMS to the RGB at solar metallicity
- Star-planet interactions: II. Is planet engulfment the origin of fast rotating red giants?
- Why is there a Dearth of Close-In Planets around Fast-Rotating stars?
- Tidal Dissipation in WASP-12
- POET: A Model for (P)lanetary (O)rbital (E)volution due to (T)ides on Evolving Stars
- Planetary Engulfment in the Hertzsprung--Russell Diagram
- Dynamical tides in exoplanetary systems containing Hot Jupiters: confronting theory and observations
- Stars Get Dizzy After Lunch
- On the Nature of Rapidly Rotating Single Evolved Stars