@GregMiller it would be great if you could turn that helpful comment into a helpful answer. The OP has what they need, but the question may be relevant for someone else in the future, and comments aren't permanent... :-)

@DarthPseudonym Great comment – I always find comparisons helpful! Further factoids: according to this paper, (a) Venus-from-Earth is -2.98 at inferior conjunction with Sun (i.e. during transit) – surprisingly bright even at its faintest; (b) Jupiter and Mars share the same max, at -2.94; and (c) Jupiter-from-Ceres is therefore about 70% brighter than Mars-from-Earth at their respective maxima. That's quite bright!

I think people are failing to understand the underlying basis of an admittedly poorly-worded question. It's seeking the missing element (pun intended) in a line of logic: (1) Do we know for a fact that there are molecules elsewhere in the solar system that are not found (or exceedingly rare) on Earth? If yes, (2) I can use this as the basis for my story that involves non-Earthly compounds, that (3) will be used to create a thing that enables a new form of space travel. Let's not get hung up about whether the plot is credible; it's an interesting astronomy question.

@uhoh I think your comments are enough to constitute an answer – even if you simply cut and pasted them (retaining the hyperlinks, of course). Comments aren't permanent, and it's always possible that someone down the track might be looking for info on SGP4 that your answer might help with. If the question is closed for lack of detail, it probably won't get auto-deleted, so it will remain in our Astronomy.SE library – and your answer would therefore remain a potentially useful resource. If you're disinclined to do so, I'd consider using your comments as a community wiki answer. Thoughts? :-)

AFAIK the CNO cycle starts at quite a bit lower than 20 million K, so I'm not sure where Wikipedia gets that figure from. The actual temperature for fusion to commence isn't the issue, nor is the surface temperature: the OP is understandably confused about how the accreted hydrogen can get so much hotter than the surface it's being heated by.

This summarises what a black hole is and what happens when it ceases to be, but it completely fails to answer the OP's question – i.e. "does an evaporating black hole remain a black hole until it evaporates [or] does it change into something else ... below a certain mass?" [my emphasis].