Epoch J2000.0 Equinox J2000.0 (ICRS)
|Right ascension||12h 38m 49.93s|
|Declination||-49° 48′ 01.2″|
|Apparent magnitude (V)||14.0|
|Variable type||DAV (ZZ Ceti)|
|Radial velocity (Rv)||−12 km/s|
|Parallax (π)||61.0 ± 9.4 mas|
|Distance||approx. 53 ly
(approx. 16 pc)
|Surface gravity (log g)||8.81 ± 0.05|
|Temperature||11730 ± 350 K|
V886 Cen, BPM 37093, GJ 2095, LFT 931, LHS 2594, LTT 4816, WD 1236-495
V886 Centauri (BPM 37093) is a variable white dwarf star of the DAV, or ZZ Ceti, type, with a hydrogen atmosphere and an unusually high mass of approximately 1.1 times the Sun's. It is about 50 light-years from Earth, in the constellation Centaurus, and vibrates; these pulsations cause its luminosity to vary. Like other white dwarfs, V886 Centauri is thought to be composed primarily of carbon and oxygen, which are created by thermonuclear fusion of helium nuclei in the triple-alpha process.
In the 1960s, it was predicted that as a white dwarf cools, its material should crystallize, starting at the center. When a star pulsates, observing its pulsations gives information about its structure. V886 Centauri was first observed to be a pulsating variable in 1992, and in 1995 it was pointed out that this yielded a potential test of the crystallization theory. In 2004, Antonio Kanaan and a team of researchers of the Whole Earth Telescope estimated, on the basis of these asteroseismological observations, that approximately 90% of the mass of V886 Centauri had crystallized. Other work gives a crystallized mass fraction of between 32% and 82%. Any of these estimates would result in a total crystalline mass in excess of 5×1029 kilograms.
Crystallization of the material of a white dwarf of this type is thought to result in a body-centered cubic lattice of carbon and/or oxygen nuclei, which are surrounded by a Fermi sea of electrons.
In Popular Culture 
- Since a diamond also consists of crystallized carbon, the star V886 Centauri has been nicknamed Lucy after The Beatles's hit Lucy in the Sky with Diamonds.
- The star is mentioned as trivia in the Modern Marvels episode "Carbon", and is said to be 10 billion trillion trillion carats. 
- In the science fiction novel Count to a Trillion by John C. Wright, this star is mined for antimatter.
See also 
- List of star extremes
- WASP-12b, a "diamond planet"
- PSR J1719-1438 b, the crystalline remnant of an evaporated white dwarf
- V886 Centauri, query result in SIMBAD. Accessed on line April 1, 2008.
- A Catalog of Spectroscopically Identified White Dwarfs, George P. McCook and Edward M. Sion, Astrophysical Journal Supplement 121, #1 (March 1999), pp. 1–130. CDS ID III/210.
- Photometric and Spectroscopic Analysis of Cool White Dwarfs with Trigonometric Parallax Measurements, P. Bergeron, S. K. Leggett, María Teresa Ruiz, Astrophysical Journal Supplement 133, #2 (April 2001), pp. 413–449. Bibcode: 2001ApJS..133..413B
- Whole Earth Telescope observations of BPM 37093: a seismological test of crystallization theory in white dwarfs, A. Kanaan, A. Nitta, D. E. Winget, S. O. Kepler, M. H. Montgomery, T. S. Metcalfe, et al., Astronomy and Astrophysics 432, #1 (March 2005), pp. 219–224. Bibcode: 2005A&A...432..219K doi:10.1051/0004-6361:20041125.
- P. Brassard, G. Fontaine, Asteroseismology of the Crystallized ZZ Ceti Star BPM 37093: A Different View, Astrophysical Journal 622, #1, pp. 572–576. Bibcode: 2005ApJ...622..572B
- Late stages of evolution for low-mass stars, Michael Richmond, lecture notes, Physics 230, Rochester Institute of Technology, accessed online May 3, 2007.
- Testing White Dwarf Crystallization Theory with Asteroseismology of the Massive Pulsating DA Star BPM 37093, T. S. Metcalfe, M. H. Montgomery, and A. Kanaan, Astrophysical Journal 605, #2 (April 2004), pp. L133–L136. Bibcode: 2004ApJ...605L.133M
- The discovery of a new DAV star using IUE temperature determination, A. Kanaan, S. O. Kepler, O. Giovannini, and M. Diaz, Astrophysical Journal Letters 390, #2 (May 10, 1992), pp. L89–L91. Bibcode: 1992ApJ...390L..89K
- The Status of White Dwarf Asteroseismology and a Glimpse of the Road Ahead, D. E. Winget, Baltic Astronomy 4 (1995), pp. 129–136. Bibcode: 1995BaltA...4..129W
- BBC News: Diamond star thrills astronomers
- Press release, 2004, Harvard-Smithsonian Center for Astrophysics.
- Crystallization of carbon-oxygen mixtures in white dwarfs, J. L. Barrat, J. P. Hansen, and R. Mochkovitch, Astronomy and Astrophysics 199, #1–2 (June 1988), pp. L15–L18. Bibcode: 1988A&A...199L..15B
- BPM 37093 (Diamond Star)
- Largest diamond in galaxy predicts future of solar system, Pravda.ru, December 26, 2007.