What are the different types of dwarf stars?

There are four main types of dwarf stars: red dwarfs, white dwarfs, brown dwarfs, and yellow dwarfs.

Red dwarfs are the most common type of dwarf star, with a mass of less than half that of the sun. They are also the coolest and dimmest type of dwarf star, with a surface temperature of less than 4,000 Kelvin. Despite their small size, they can live for trillions of years.

White dwarfs are the remnants of stars that have exhausted their nuclear fuel and shed their outer layers. They are incredibly dense, with a mass similar to that of the sun but a size comparable to that of the earth. They are also incredibly hot, with a surface temperature of up to 100,000 Kelvin.

Brown dwarfs are often referred to as "failed stars" because they are too small to sustain nuclear fusion in their cores and become full-fledged stars. They are larger than gas giants like Jupiter but smaller than red dwarfs, with a mass between 13 and 80 times that of Jupiter.

Yellow dwarfs, like our sun, are main-sequence stars that fuse hydrogen into helium in their cores. They are the most familiar type of star, with a surface temperature of around 5,500 Kelvin and a lifespan of around 10 billion years.