Helium Depletion in Escaping Atmospheres of Sub-Neptunes: A Signature of Primary-to-Secondary Transition

Issei Kobayashi, Hiroyuki Kurokawa, Laura Schaefer +1

Short-period sub-Neptunes are common in extrasolar systems. These sub-Neptunes are generally thought to have primary atmospheres of protoplanetary-disk gas origin. However, atmosph…