Van Maanen's Star
Van Maanen's star | |
Stellar characteristics | |
---|---|
Constellation | Pisces |
Right ascension (Epoch J2000) | 00h 49m 09.8992s |
Declination (Epoch J2000) | +05° 23' 19.007" |
Spectral type | DZ7 |
Distance from Sol | 14.1 ± 0.1 ly |
Other designations | van Maanen 2, Wolf 28, G 001-027, G 70-16, Gliese 35, GCTP 160.00, HIP 3829, LFT 76, LHS 7, LTT 10292, WD 0046+05, WD 0046+051, W 5 |
This dim object is located only about 14.4 light-years (ly) from our Sun, Sol. It lies in the center (00:49:09.90+05:23:19.01, ICRS 2000.0) of Constellation Pisces, the Fish -- west of Delta Piscium and east of Omega Piscium. As a white dwarf stellar remnant, this object is too faint to be seen with the naked eye.
Its significance as a very close Solar neighbor was discovered in 1917 by Adriaan van Maanen (1884-1946) who, in comparing photographs made between 1914 and 1917, noticed its high proper motion of 2.98" annually.
Van Maanen's Star (also known as Van Maanen 2) is a stellar remnant of spectral and luminosity type DZ7 or DF-G /VII. As a DZ white dwarf, it is relatively cool with metallic but no hydrogen or helium lines in its spectrum (Weidemann and Koester, 1989). It is the closest white dwarf to Sol without a stellar companion (i.e., as a stand-alone object), and its relative coolness suggests that it is a very old star, perhaps near or older than 10 billion years, but recent studies have presumed an age of 3.7 to 5 billion years based on cooling age, particularly in searches for a detectable brown dwarf companion (Burleigh et al, 2008; and Farihi et al, 2004; Bergeron et al, 2001).
Van Maanen's Star has about 0.57 to 0.63 (up to a modelled 0.83) of Sol's mass (Burleigh et al, 2008; Farihi et al, 2004; Bergeron et al, 2001; and Volker Weidemann, 1960), but with only about 1.3 percent of of its diameter (Gatewood and Russell, 1974), and less than 2/10,000th of its brightness. White dwarfs are incredibly dense objects because they squeeze a stellar mass into a planetary volume. According to Robert Burnham, Jr., Van Maanen's Star has a computed diameter of about 7,800 miles (just under the Earth's diameter of 7,930 miles), which results in a density of about 20 tons to the cubic inch, or about 10 times the computed density of Sirius B, the closest known white dwarf. While tiny compared to main sequence stars, white dwarf stars are actually intensely hot, but without the internal heat of fusion to keep them burning, they gradually cool and fade away.
(Boilerplate taken from SolStation.com)