That means that sub-Neptunes will evolve differently depending on the exact upper atmosphere composition, even if they're always hydrogen-dominated. We find that the opacity ratios can make a difference between very little atmosphere being retained under core-powered mass loss, or nearly all. 8/10

The difference in mass loss rates for different opacity ratios is biggest when the atmospheres are most contracted, with up to a factor of 10^10 in mass loss rate separating cold upper atmospheres from hot ones! We provide tabulated rates in case you'd like to use these numbers yourself. 7/10

What we found is that the opacities have big implications for escape from sub-Neptunes: hotter temperature profiles lead to more mass loss! The most important reason why is that the density falls off more slowly if the temperatures are higher, leading to higher escape rates. 6/10

If the ratio (termed gamma) is near 1, then the atmosphere is roughly isothermal, but if it's not, you can get cool stratospheres or thermal inversions. This won't come as news to a lot of exoplaneteers, as we've long seen evidence for the phenomenon in atmospheric spectra! 4/10

Core-powered mass loss, one of the mechanisms that can explain the radius valley separating the super-Earths and sub-Neptunes, has always been modeled using an analytic escape rate calculation, called a Parker wind, that assumed the outer atmosphere was isothermal at the equilibrium temperature 2/10

Excited for my first-ever (!) AAS this week. Look out for my thesis talk, conveniently on Monday morning to ease you back into conferencing:
133.05D “Coupled chemistry and structure of sub-Neptune atmospheres: a window into the interior”
Mon, Jan 8 10:40-11:00am
Room R04 #AAS243