In the last 20 years, the hunt for planetary systems which may be habitable has uncovered dozens of oddities. A few of these planets have novel chemistry which could be consistent with denser forms of hydrogen.
There are many findings of hot Jupiter sized planets which are hotter than our sun and Neptune sized planets which are both hot and icy. Some of these discoveries hint at unique chemistry which could be consistent with dense molecular hydrogen including collapsing hydrogen as a non-fusion heat source.. Here is a story on a planet about the size of our Neptune but covered in what appears to be hot yet solid water (aka “ice”). https://www.universetoday.com/1650/neptune-sized-planet-covered-in-superhot-ice/ Water can remain solid under intense gravity even when it would be superheated steam on earth. Unsaid by any paper is that when composed of oxygen and dense hydrogen, a whole new set of assumptions are presented which have become controversial implications of the work of Mills Holmlid and others. … then for Vonnegut fans, there is the already well-known ice-nine… which conception may turn out to be prescient. Anyway, there are many new planets which are completely unexpected and one is a most dramatic extrasolar planetary discovery - a Neptune-sized large planet which is close enough to its parent star to be extremely hot – above 400 F in shade on average. The assumption is that it is heated by its sun, but that may not be the only source of heat. Since, even at oven temperatures, large oceans of solid ice are detected and little else is certain. The announcement was made in the paper Detection of transits of the nearby hot Neptune GJ 436 b, in the journal Astronomy and Astrophysics Letters. Or here https://arxiv.org/abs/0705.2219
