X-ray emission from the super-Earth host GJ 1214

TL;DR

This study detects X-ray emission from GJ 1214, a super-Earth host star, and estimates the planetary atmospheric mass loss due to stellar irradiation, providing insights into planetary evolution.

Contribution

First detection of X-ray emission from GJ 1214, quantifying stellar activity and planetary atmospheric evaporation rates.

Findings

X-ray luminosity LX=7.4E25 erg/s

Planet GJ 1214 b loses ~2-5.6 Earth masses over time

Coronal temperature around 3.5 million Kelvin

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 an XMM-Newton observation. We derive an X-ray luminosity LX=7.4E25 erg/s and a corresponding activity level of log(LX/Lbol)~ -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 1.3E10 g/s and has lost a total of ~2-5.6 MEarth.