Where they spell out a formula for the speed of sound in this type of planet given some assumptions. It's beyond my understanding, but I thought it was pretty cool. Section 4.4 if you want to have a look.
Very cool! Isn't it amazing what happens when you don't assume bad faith or incompetence on the part of the researchers? You have to like a paper that has a section discussing the precipitation of vaporized iron out of a planets atmosphere...mindblowing. Of course, that means doing a little homework to actually understand what they already know and avoiding the lazy "me and my preconceived notions and lack of domain knowledge are here to tell you why your wrong".