X-ray irradiation and evaporation of the four young planets around V1298 Tau
| Autor: | Laura Ketzer, Matthias Mallonn, Katja Poppenhaeger |
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| Rok vydání: | 2020 |
| Předmět: |
Astrophysics::High Energy Astrophysical Phenomena
FOS: Physical sciences Astrophysics Astrophysics::Cosmology and Extragalactic Astrophysics Star (graph theory) 01 natural sciences Planet 0103 physical sciences ROSAT Astrophysics::Solar and Stellar Astrophysics 010303 astronomy & astrophysics Astrophysics::Galaxy Astrophysics Solar and Stellar Astrophysics (astro-ph.SR) Spin-½ Physics Earth and Planetary Astrophysics (astro-ph.EP) 010308 nuclear & particles physics Astronomy and Astrophysics Radius Exoplanet Stars Astrophysics - Solar and Stellar Astrophysics Space and Planetary Science Extreme ultraviolet Astrophysics::Earth and Planetary Astrophysics Astrophysics - Earth and Planetary Astrophysics |
| DOI: | 10.48550/arxiv.2005.10240 |
| Popis: | Planets around young stars are thought to undergo atmospheric evaporation due to the high magnetic activity of the host stars. Here we report on X-ray observations of V1298 Tau, a young star with four transiting exoplanets. We use X-ray observations of the host star with Chandra and ROSAT to measure the current high-energy irradiation level of the planets, and employ a model for the stellar activity evolution together with exoplanetary mass loss to estimate the possible evolution of the planets. We find that V1298 Tau is X-ray bright with $\log L_X$ [erg/s] $=30.1$ and has a mean coronal temperature of $\approx 9$ MK. This places the star amongst the more X-ray luminous ones at this stellar age. We estimate the radiation-driven mass loss of the exoplanets, and find that it depends sensitively on the possible evolutionary spin-down tracks of the star as well as on the current planetary densities. Assuming the planets are of low density due to their youth, we find that the innermost two planets can lose significant parts of their gaseous envelopes, and could be evaporated down to their rocky cores depending on the stellar spin evolution. However, if the planets are heavier and follow the mass-radius relation of older planets, then even in the highest XUV irradiation scenario none of the planets is expected to cross the radius gap into the rocky regime until the system reaches an age of 5 Gyr. Comment: Accepted for publication in MNRAS. 14 pages |
| Databáze: | OpenAIRE |
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