A High-Resolution Non-Detection of Escaping Helium In The Ultra-Hot Neptune LTT 9779b: Evidence for Weakened Evaporation

Shreyas Vissapragada, Patrick McCreery, Leonardo A. Dos Santos +16

The recent discovery of ``ultra-hot'' ($P<1$ day) Neptunes has come as a surprise: some of these planets have managed to retain gaseous envelopes despite being close enough to th…