Dragon's Egg

Dragon's Egg was written by American physicist and author Robert L. Forward. It was originally published in 1980 and is considered a cornerstone of hard science fiction literature.

The novel is set on the surface of a neutron star and depicts an alien species called the cheela, who are composed of neutron-star matter. Because of their intense gravity and biology, their civilization operates at vastly accelerated rates compared to humans, living entire lifetimes in roughly a month.

Yes, Forward wrote a direct sequel titled Starquake! in 1985. The sequel continues the story of human contact with the cheela and explores the catastrophic effects of a stellar phenomenon on their fragile neutron star society.

Because Robert L. Forward was a professional physicist, the novel is incredibly grounded in actual astrophysics, gravity, and orbital mechanics. The book is celebrated for its rigorous scientific extrapolation of what life might look like on a surface with a gravity billions of times that of Earth.