X-Ray Emission from the Super-Earth Host GJ 1214

Abstract

Stellar activity can produce large amounts of high-energy radiation, which is absorbed by the planetary atmosphere leading to irradiation-driven mass loss. We present the detection and an investigation of high-energy emission in a transiting super-Earth host system, GJ 1214, based on XMM-Newton observations. We derive an X-ray luminosity of L_X = 7.4 × 10²⁵ erg s^-1 and a corresponding activity level of log (L_X /L _bol) ~ -5.3. Further, we determine a coronal temperature of about ~3.5 MK, which is typical for coronal emission of moderately active low-mass stars. We estimate that GJ 1214 b evaporates at a rate of 1.3× 10¹⁰ g s^-1 and has lost a total of ≈2-5.6 M _⊕.