Greetings. According to my Geology textbook (it is about astronomy, i wonder why we have this in the Geology textbook) : (sorry if translation is not really good) The text may seem a little bit confusing, but let me give you the summary. The book says that a star may become a dwarf when the nuclear reactions in it stops, and later the book says that dwarf have high temprature. My question is: Where does the temprature of the Dwarf comes if the nuclear reactions are over ? Thanks in advance.