The XUV environments of exoplanets from Jupiter-size to super-Earth

George W. King, Peter J. Wheatley, Michael Salz, Vincent Bourrier, Stefan Czesla, David Ehrenreich, James Kirk, Alain Lecavelier des Etangs, Tom Louden, Jürgen Schmitt, P. Christian Schneider
(Submitted on 30 Apr 2018)

Planets that reside close-in to their host star are subject to intense high-energy irradiation. Extreme-ultraviolet (EUV) and X-ray radiation (together, XUV) is thought to drive mass loss from planets with volatile envelopes. We present $\textit{XMM-Newton}$ observations of six nearby stars hosting transiting planets in tight orbits (with orbital period, $P_\text{orb} < 10\,$d), wherein we characterise the XUV emission from the stars and subsequent irradiation levels at the planets. In order to reconstruct the unobservable EUV emission, we derive a new set of relations from Solar $\textit{TIMED/SEE}$ data that are applicable to the standard bands of the current generation of X-ray instruments. From our sample, WASP-80b and HD$\,$149026b experience the highest irradiation level, but HAT-P-11b is probably the best candidate for Ly$\,\alpha$ evaporation investigations because of the system's proximity to the Solar System. The four smallest planets have likely lost a greater percentage of their mass over their lives than their larger counterparts. We also detect the transit of WASP-80b in the near ultraviolet with the Optical Monitor on $\textit{XMM-Newton}$. Comments:    17 pages, 14 figures, 8 tables; accepted for publication in MNRAS
Subjects:    Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)
Cite as:    arXiv:1804.11124 [astro-ph.EP] (or arXiv:1804.11124v1 [astro-ph.EP] for this version)
Submission history
From: George King 
[v1] Mon, 30 Apr 2018 11:22:54 GMT (2016kb,D)
https://arxiv.org/abs/1804.11124