2020RNAAS...4..231P

The He I 10830 Å absorption line in transit spectra traces the upper atmospheres of exoplanets and their mass loss, which in turn is important in determining their evolution and demographics. We use archival VLT/X-Shooter data to set new, more sensitive limits on the extended helium atmosphere of GJ 1214 b, a sub-Neptune orbiting an M-dwarf. We determine limits for the excess absorption at 10830 Å of 0.38% ± 0.44%, which corresponds to an extended atmosphere scale height of 0.13 ± 0.14R_p (95% confidence limit of <0.4R_p). This is an improvement on previous upper limits set by Crossfield et al. () and shows that X-shooter is a suitable instrument for these types of observations.