BPM 37093

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BPM 37093
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Centaurus
Right ascension  12h 38m 49.93s[1]
Declination −49° 48′ 01.2″[1]
Apparent magnitude (V) 14.0[1]
Spectral type DAV4.4[2]
Variable type DAV (ZZ Ceti)[2]
Radial velocity (Rv)−12[2] km/s
Parallax (π)61.0 ± 9.4[3] mas
Distanceapprox. 53 ly
(approx. 16 pc)
Mass1.10[4] M
Radius0.0057 R
Luminosity0.001[3] L
Surface gravity (log g)8.81 ± 0.05[5] cgs
Temperature11730 ± 350[5] K
Other designations
V886 Cen, BPM 37093, GJ 2095, LFT 931, LHS 2594, LTT 4816, WD 1236-495[1]
Database references

BPM 37093 (V886 Centauri) 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.[1][4] Like other white dwarfs, BPM 37093 is thought to be composed primarily of carbon and oxygen, which are created by thermonuclear fusion of helium nuclei in the triple-alpha process.[6]


In the 1960s, it was predicted that as a white dwarf cools, its material should crystallize, starting at the center.[7] When a star pulsates, observing its pulsations gives information about its structure. BPM 37093 was first observed to be a pulsating variable in 1992,[8] and in 1995 it was pointed out that this yielded a potential test of the crystallization theory.[9] 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 BPM 37093 had crystallized.[4][7][10][11] Other work gives a crystallized mass fraction of between 32% and 82%.[5] Any of these estimates would result in a total crystalline mass in excess of 5×1029 kilograms. As the white dwarf has a diameter of 4,000-kilometre (2,500 mi), this means that the core of BPM 37093, nicknamed Lucy, is likely one of the largest diamonds in the universe.[12][13]

Body-centered cubic lattice

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.[14]

Nickname and press coverage[edit]

In popular culture[edit]

  • In John C. Wright's science fiction novel, "Count to a Trillion" and its sequels, V886 Centauri is called the "Diamond Star", after the crystalline carbon core. In the story of the novel, it becomes the destination of the first human interstellar journey after it is discovered that the star, a ten-decillion-carat diamond of degenerate matter, is not matter at all, but antimatter. An alien artifact called "The Monument" is found orbiting it, which increases human knowledge of mathematics immensely.
  • In Jim Jarmusch's 2013 film Only Lovers Left Alive, Tilda Swinton's character Eve tells Tom Hiddleston's character Adam about BPM 37093, describing it as a "diamond up there the size of a planet" that "emits the music of a gigantic gong."

See also[edit]


  1. ^ a b c d e "WG 22". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved April 1, 2008.
  2. ^ a b c 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.
  3. ^ a b 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. Bibcode2001ApJS..133..413B
  4. ^ a b c 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. Bibcode2005A&A...432..219K doi:10.1051/0004-6361:20041125.
  5. ^ a b c P. Brassard, G. Fontaine, Asteroseismology of the Crystallized ZZ Ceti Star BPM 37093: A Different View, Astrophysical Journal 622, #1, pp. 572–576. Bibcode2005ApJ...622..572B
  6. ^ Late stages of evolution for low-mass stars, Michael Richmond, lecture notes, Physics 230, Rochester Institute of Technology, accessed online May 3, 2007.
  7. ^ a b 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. Bibcode2004ApJ...605L.133M
  8. ^ 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. Bibcode1992ApJ...390L..89K
  9. ^ The Status of White Dwarf Asteroseismology and a Glimpse of the Road Ahead, D. E. Winget, Baltic Astronomy 4 (1995), pp. 129–136. Bibcode1995BaltA...4..129W
  10. ^ a b BBC News: Diamond star thrills astronomers
  11. ^ Press release, 2004, Harvard-Smithsonian Center for Astrophysics.
  12. ^ "This Valentine's Day, Give The Woman Who Has Everything The Galaxy's Largest Diamond". Center for Astrophysics. Retrieved May 5, 2009.
  13. ^ "Lucy's in the Sky with Diamonds: Meet the Most Expensive Star Ever Found". Futurism. 12 June 2014. Retrieved 20 May 2019.
  14. ^ 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. Bibcode1988A&A...199L..15B

External links[edit]