Van Maanen's star (van Maanen 2) is a white dwarf star. Out of the white dwarfs known, it is the third closest to the Sun, after Sirius B and Procyon B, in that order, and the closest known solitary white dwarf.69 Discovered in 1917 by Adriaan van Maanen, Van Maanen's star was the third white dwarf identified, after 40 Eridani B and Sirius B, and the first that was not a member of a multi-star system.
Van Maanen's star is located 14.1 light years from the Sun in the constellation Pisces, and has a relatively high proper motion of 2.98" annually. It is far too faint to be seen with the naked eye. Like other white dwarfs, it is a very dense star: its mass has been estimated to be about 70% of the Sun's, and its radius is roughly 1% of the Sun's. It is under 2/10,000 times as luminous as the Sun, and has a relatively cool temperature of approximately 6750 K. As white dwarfs cool with time, the star's temperature can be used to estimate its age, thought to be around 4 billion years.
The stellar classification of this white dwarf is DZ8, where the DZ indicates the presence of elements heavier than helium in the spectrum. Indeed, this star is the prototype for white dwarfs of this class. Based upon physical models of white dwarfs, it is believed that elements with mass greater than helium should sink below the photosphere of the star, leaving only hydrogen and helium to be visible in the spectrum. Hence, for heavier elements to appear, there must have been an external source. It is thought unlikely that the heavy elements were obtained from the interstellar medium. Instead, the surface of the star was likely polluted by circumstellar material, such as by the remains of a rocky, terrestrial planet.
Van Maanen's Star in space opera:
- Frontier: Elite II? and Frontier: First Encounters, computer games. The Van Maanen's Star system is the home of a radical religious sect that believes in suffering as the key to salvation. Mining is done without machines, and any surplus money that is not needed to satisfy basic requirements like oxygen, food and water is burned in a sacred ceremony. The system is only accessible with a special permit. Due to the banning of ordinary trade items, Van Maanen's is a haven for smugglers.
- In C. J. Cherryh's Alliance-Union universe, van Maanen's star is host to the star station Mariner.