sentence: Some white dwarfs are blue, instead of white.
sentences_before: A 'white dwarf' is a star. The colour of a white dwarf is like most other stars, but not as bright. White Dwarfs were discovered in the 19th century, and the first ones found were white. The colour of a star is a measure of how hot it is, white stars are like the Sun, blue stars are hotter, and red stars are cooler. White dwarfs are not very bright because they are smaller than many brighter stars - not because they are cold.
concept_name: white dwarf
headings: White dwarf
categories: Types of stars