Bringing Heat by Viola Grace

Her life on Earth had died decades earlier; helping to bring heat to a frozen world seems like a good use of her time.
The love of her life died when they were teens, and Idalia had no plans for any kind of future. When a woman named Minerva arrived near the lighthouse where she spent her days escorting tourists and made Idalia an offer, it was a no-brainer. Nothing or something. She chose something to bring her life out of the lock she had been in.

The process to change her body to enable her to survive Los was detailed and altered every bit of tissue and bone she had.

Taunting a planet’s avatar into reappearing using sex isn’t something one can train for, but Idalia has a good instinct for it, and he soon rises to claim her, body and soul.