Gravity star theory models are disproven by the Kavli Foundation by showing that the transfer of ALL hydrogen gas to the lesser mass binary companion star, leaves behind a low mass helium star that supernovas. Logically, this is done by a phase change of what became pure helium gas into a cold He3 and He4 superfluid core, that was not possible when the star contained all it's hydrogen. Superfluid helium is already proven to mathematically analog black holes in physics laboratories.A four solar mass superfluid helium star supernovas, after the formerly more massive star unexplainably transfers over a long period of time, most of it's mass in the form of hydrogen to the smaller binary companion star. This is astrochemistry and phase changes of matter, and not gravity. The findings provide strong evidence for a superfluid helium supernova, which is not another hydrogen model for gravity theories that say more massive stars burn hydrogen quickly and then explode when they run out of it.
Here is the complete and original news story by the Kavli Foundation: