Ok, my turn.
I have vague memories of this great sci-fi novel I enjoyed in my younger days. It was based around life on a white star. On one side was this alien species that lived its day on the white star, and on the other side were humans, perhaps? Life on the white star was subject to a sort of time dilation, so every hour the humans talked to the creatures it was a year of their lives (or something akin to that). Eventually they made robots or other artificial creatures to talk to the humans so they wouldn’t have to sacrifice a year just for a conversation.
I don’t remember much else except I remember at the end of the book the author had pages and pages of mathematical proofs to show that life on a white dwarf star was at least conceivable. I just remember the central plot.