Year: 2017
Type: article
Abstract: Some close-in gaseous exoplanets are nearly in Roche lobe contact, and previous studies show that tidal decay can drive hot Jupiters into contact during the main sequence of their host stars. Improving on a previous model, we present a revised model for mass transfer in a semidetached binary system that incorporates an extended atmosphere around the donor and allows for an arbitrary mass ratio. We apply this new formalism to hypothetical, confirmed, and candidate planetary systems to estimate mass-loss rates and compare with models of evaporative mass loss. Overflow may be significant for hot Neptunes out to periods of ∼2 days, while for hot Jupiters, it may only be important inward of 0.5 days. We find that CoRoT-24 b may be losing mass at a rate of more than an Earth mass in a gigayear. The hot Jupiter WASP-12 b may lose an Earth mass in a megayear, while the putative planet PTFO8-8695 orbiting a T Tauri star might shed its atmosphere in a few megayears. We point out that the orbital expansion that can accompany mass transfer may be less effective than previously considered because the gas accreted by the host star removes some of the angular momentum from the orbit, but simple scaling arguments suggest that the Roche lobe overflow might remain stable. Consequently, the recently discovered small planets in ultrashort periods (<1 day) may not be the remnants of hot Jupiters/Neptunes. The new model presented here has been incorporated into Modules for Experiments in Stellar Astrophysics (MESA).
Source: The Astrophysical Journal
Authors: Brian Jackson, Phil Arras, Kaloyan Penev, Sarah Peacock, Pablo Marchant
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
Awards: G2171960263, THE ORIGINS OF CLOSE-IN EXTRASOLAR PLANETS WE WILL STUDY THE ROLES OF TIDAL DISSIPATION WITHIN PLANET-HOSTING STARS AND THE PLANETS THEMSELVES IN THE, G433322167, THE MULTI-MISSION ARCHIVE AT SPACE TELESCOPE SCIENCE INSTITUTE (MAST) IS NASA'S ARCHIVE CENTER FOR OPTICAL/UV SPACE ASTROPHYSICS DATA. MAST PROVIDE, G58316358, G6273510985, THE UPPER ATMOSPHERES OF GAS GIANT EXOPLANETS ORBITING CLOSE TO THEIR PARENT STAR ARE HEATED AND IONIZED BY ENERGETIC STELLAR PHOTONS.BOTH GROUND-BAS
OpenAlex ID: W2566209400