BPM 37093

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BPM 37093
V886CenLightCurve.png
A light curve for V886 Centauri, adapted from Kanaan et al. (1992) [1]
Observation data
Epoch J2000.0        Equinox J2000.0 (ICRS)
Constellation Centaurus
Right ascension 12h 38m 49.78112s [2]
Declination −49° 48′ 00.2195″ [2]
Apparent magnitude  (V)14.0 [3]
Characteristics
Spectral type DAV4.4 [4]
Variable type DAV (ZZ Ceti) [4]
Astrometry
Radial velocity (Rv)−12 [4]  km/s
Proper motion (μ)RA: -557.111  mas/yr [2]
Dec.: -74.036  mas/yr [2]
Parallax (π)67.4058 ± 0.0186  mas [2]
Distance 48.39 ± 0.01  ly
(14.836 ± 0.004  pc)
Details
Mass 1.10 [5]   M☉
Radius 0.0057  R☉
Luminosity 0.001 [6]   L☉
Surface gravity (log g)8.81 ± 0.05 [7]   cgs
Temperature 11730 ± 350 [7]   K
Other designations
V886  Cen, BPM 37093, GJ  2095, LFT 931, LHS 2594, LTT 4816, WD 1236-495 [3]
Database references
SIMBAD data
ARICNS data

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 48 light-years (15 parsecs ) from Earth in the constellation Centaurus and vibrates; these pulsations cause its luminosity to vary. [3] [5] 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. [8]

Contents

Structure

In the 1960s, it was predicted that as a white dwarf cools, its material should crystallize, starting at the center. [9] When a star pulsates, observing its pulsations gives information about its structure. BPM 37093 was first observed to be a pulsating variable in 1992, [1] and in 1995 it was pointed out that this yielded a potential test of the crystallization theory. [10] 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. [5] [9] [11] [12] Other work gives a crystallized mass fraction of between 32% and 82%. [7] Any of these estimates would result in a total crystalline mass in excess of 5×1029 kilograms. As the white dwarf has a radius of 4,000 kilometres (2,500 mi), this means that the core of BPM 37093, nicknamed Lucy, is likely one of the largest diamonds in the local region of the universe. [13] [14]

Body-centered cubic lattice Lattice body centered cubic.svg
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. [15]

Nickname and press coverage

See also

Related Research Articles

<span class="mw-page-title-main">White dwarf</span> Type of stellar remnant composed mostly of electron-degenerate matter

A white dwarf is a stellar core remnant composed mostly of electron-degenerate matter. A white dwarf is very dense: its mass is comparable to the Sun's, while its volume is comparable to the Earth's. A white dwarf's low luminosity comes from the emission of residual thermal energy; no fusion takes place in a white dwarf. The nearest known white dwarf is Sirius B, at 8.6 light years, the smaller component of the Sirius binary star. There are currently thought to be eight white dwarfs among the hundred star systems nearest the Sun. The unusual faintness of white dwarfs was first recognized in 1910. The name white dwarf was coined by Willem Luyten in 1922.

<span class="mw-page-title-main">Photosphere</span> Stars outer shell from which light is radiated

The photosphere is a star's outer shell from which light is radiated.

<span class="mw-page-title-main">G 29-38</span> White dwarf which undergoes characteristic variability

Giclas 29-38, also known as ZZ Piscium, is a variable white dwarf star of the DAV type, whose variability is due to large-amplitude, non-radial pulsations known as gravity waves. It was first reported to be variable by Shulov and Kopatskaya in 1974. DAV stars are like normal white dwarfs but have luminosity variations with amplitudes as high as 30%, arising from a superposition of vibrational modes with periods from 100 to 1,000 seconds. Large-amplitude DAVs generally differ from lower-amplitude DAVs by having lower temperatures, longer primary periodicities, and many peaks in their vibrational spectra with frequencies which are sums of other vibrational modes.

<span class="mw-page-title-main">HL Tau 76</span> Star in the constellation Taurus

HL Tau 76 is a variable white dwarf star of the DAV type. It was observed by G. Haro and W. J. Luyten in 1961, and was the first variable white dwarf discovered when, in 1968, Arlo U. Landolt found that it varied in brightness with a period of approximately 749.5 seconds, or 12.5 minutes. Like other DAV white dwarfs, its variability arises from non-radial gravity wave pulsations within itself., § 7. Later observation and analysis has found HL Tau 76 to pulsate in over 40 independent vibrational modes, with periods between 380 seconds and 1390 seconds.

A pulsating white dwarf is a white dwarf star whose luminosity varies due to non-radial gravity wave pulsations within itself. Known types of pulsating white dwarfs include DAV, or ZZ Ceti, stars, with hydrogen-dominated atmospheres and the spectral type DA; DBV, or V777 Her, stars, with helium-dominated atmospheres and the spectral type DB; and GW Vir stars, with atmospheres dominated by helium, carbon, and oxygen, and the spectral type PG 1159. GW Vir stars may be subdivided into DOV and PNNV stars; they are not, strictly speaking, white dwarfs but pre-white dwarfs which have not yet reached the white dwarf region on the Hertzsprung-Russell diagram. A subtype of DQV stars, with carbon-dominated atmospheres, has also been proposed, and in May 2012, the first extremely low mass variable (ELMV) white dwarf was reported.

<span class="mw-page-title-main">G 117-B15A</span> Nearby white dwarf star in the constellation Leo Minor

G117-B15A is a small, well-observed variable white dwarf star of the DAV, or ZZ Ceti, type in the constellation of Leo Minor.

<span class="mw-page-title-main">Ross 548</span> Variable star in the constellation Cetus

Ross 548 is a white dwarf in the equatorial constellation of Cetus. With a mean apparent visual magnitude of 14.2 it is much too faint to be visible to the naked eye. Based on parallax measurements, it is located at a distance of 107 light years from the Sun. It was found to be variable in 1970 and in 1972 it was given the variable star designation ZZ Ceti. This is a pulsating white dwarf of the DAV type that is the prototype of the ZZ Ceti variable class., pp. 891, 895.

<span class="mw-page-title-main">PG 1159-035</span> Star in the constellation Virgo

PG 1159-035 is the prototypical PG 1159 star after which the class of PG 1159 stars was named. It was discovered in the Palomar-Green survey of ultraviolet-excess stellar objects and, like the other PG 1159 stars, is in transition between being the central star of a planetary nebula and being a white dwarf.

A PG 1159 star, often also called a pre-degenerate, is a star with a hydrogen-deficient atmosphere that is in transition between being the central star of a planetary nebula and being a hot white dwarf. These stars are hot, with surface temperatures between 75,000 K and 200,000 K, and are characterized by atmospheres with little hydrogen and absorption lines for helium, carbon and oxygen. Their surface gravity is typically between 104 and 106 meters per second squared. Some PG 1159 stars are still fusing helium., § 2.1.1, 2.1.2, Table 2. The PG 1159 stars are named after their prototype, PG 1159-035. This star, found in the Palomar-Green survey of ultraviolet-excess stellar objects, was the first PG 1159 star discovered.

<span class="mw-page-title-main">GD 358</span> Star in the constellation Hercules

GD 358 is a variable white dwarf star of the DBV type. Like other pulsating white dwarfs, its variability arises from non-radial gravity wave pulsations within the star itself. GD 358 was discovered during the 1958–1970 Lowell Observatory survey for high proper motion stars in the Northern Hemisphere. Although it did not have high proper motion, it was noticed that it was a very blue star, and hence might be a white dwarf. Greenstein confirmed this in 1969.

HD 115404 is a binary star system located in the constellation Coma Berenices. Parallax measurements made by Hipparcos put the system at 36 light-years, or 11 parsecs, away. The combined apparent magnitude of the system is 6.52, with the magnitudes of the components being 6.66 and 9.50.

<span class="mw-page-title-main">G 185-32</span> White dwarf in the constellation Vulpecula

G 185-32, also known by the variable star designation PY Vulpeculae, is a white dwarf in the constellation Vulpecula. Located approximately 18.3 parsecs (60 ly) distant, the stellar remnant is a ZZ Ceti variable, varying by 0.02 apparent magnitudes from the mean of 13.00.

<span class="mw-page-title-main">PG 1047+003</span> Subdwarf B star in the constellation Sextans

PG 1047+003 is a post-AGB blue-white subdwarf star, located in the constellation of Sextans. The star is classed as member of the V361 Hydrae type class of pulsators in the field of asteroseismology. No additional stellar companion has been detected in tight orbit or imaged around the subdwarf star.

<span class="mw-page-title-main">KPD 1930+2752</span>

KPD 1930+2752 is a binary star system including a subdwarf B star and a probable white dwarf with relatively high mass. Due to the nature of this astronomical system, it seems like a likely candidate for a potential type Ia supernova, a type of supernova which occurs when a white dwarf star takes on enough matter to approach the Chandrasekhar limit, the point at which electron degeneracy pressure would not be enough to support its mass. However, carbon fusion would occur before this limit was reached, releasing enough energy to overcome the force of gravity holding the star together and resulting in a supernova.

<span class="mw-page-title-main">49 Ceti</span> Star in the constellation Cetus

49 Ceti is a single star in the equatorial constellation of Cetus. It is visible to the naked eye as a dim, white-hued star with an apparent visual magnitude of 5.607. The star is located 186 light-years away from the Solar System, based on its parallax, and is drifting further away with a radial velocity of +10 km/s. 49 Ceti has been identified as a member of the 40-million-year-old Argus Association.

<span class="mw-page-title-main">GD 165</span> Star in the constellation Boötes

GD 165 is a system of a white dwarf and a brown dwarf of spectral types DA4 + L4, located in constellation Boötes at approximately 103 light-years from Earth. GD 165 B remained the only brown dwarf companion of a white dwarf until the discovery of GD 1400 B, which was discovered 17 years later.

<span class="mw-page-title-main">TY Coronae Borealis</span> Variable white dwarf star in the constellation Corona Borealis

TY Coronae Borealis, also known as Ross 808, is a variable white dwarf star of the DAV type in the constellation Corona Borealis. It has a surface temperature of 11,213 ± 130 K and a mass around 70% times that of the Sun, but only 1.1% of its diameter. It is 107 light-years distant from Earth. It was confirmed as a variable star in 1976.

Kepler de Souza Oliveira Filho, also known as S. O. Kepler, is a Brazilian astronomer primarily known for his work on white dwarfs, variable stars, and magnetars. A member of the Brazilian Academy of Sciences, he is currently a professor at Universidade Federal do Rio Grande do Sul (UFRGS).

MY Apodis, also known as L 19-2, GJ 2108, or WD 1425-811, is a single white dwarf star located in the far southern constellation Apus. It is a low-amplitude variable star with an average apparent visual magnitude of 13.75 and thus is much too faint to be visible to the naked eye. Based on parallax measurements, this star is located at a distance of 68.3 light-years from the Sun. It is drifting further away with a radial velocity of 58.0

The Whole Earth Telescope is an international network of astronomers that collaborate to study variable stars. The distribution of the observatories in longitude allow the selected targets to be continuously monitored despite the rotation of the Earth.

References

  1. 1 2 Kanaan, A.; Kepler, S. O.; Giovannini, O.; Diaz, M. (10 March 1992). "The Discovery of a New DAV Star Using IUE Temperature Determination". The Astrophysical Journal. 390: L89–L91. Bibcode:1992ApJ...390L..89K. doi:10.1086/186379. hdl:10183/108720. Archived from the original on 4 December 2021. Retrieved 4 December 2021.
  2. 1 2 3 4 5 Vallenari, A.; et al. (Gaia Collaboration) (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics . arXiv: 2208.00211 . doi: 10.1051/0004-6361/202243940 . Gaia DR3 record for this source at VizieR.
  3. 1 2 3 "WG 22". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved April 1, 2008.
  4. 1 2 3 A Catalog of Spectroscopically Identified White Dwarfs Archived 2018-08-08 at the Wayback Machine , George P. McCook and Edward M. Sion, Astrophysical Journal Supplement121, #1 (March 1999), pp. 1–130. CDS ID III/210 Archived 2013-10-22 at the Wayback Machine .
  5. 1 2 3 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 Astrophysics432, #1 (March 2005), pp. 219–224. Bibcode : 2005A&A...432..219K doi : 10.1051/0004-6361:20041125.
  6. ↑ Photometric and Spectroscopic Analysis of Cool White Dwarfs with Trigonometric Parallax Measurements, P. Bergeron, S. K. Leggett, María Teresa Ruiz, Astrophysical Journal Supplement133, #2 (April 2001), pp. 413–449. Bibcode:2001ApJS..133..413B
  7. 1 2 3 P. Brassard, G. Fontaine, Asteroseismology of the Crystallized ZZ Ceti Star BPM 37093: A Different View, Astrophysical Journal622, #1, pp. 572–576. Bibcode : 2005ApJ...622..572B
  8. ↑ Late stages of evolution for low-mass stars Archived 2020-06-11 at the Wayback Machine , Michael Richmond, lecture notes, Physics 230, Rochester Institute of Technology, accessed online May 3, 2007.
  9. 1 2 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 Journal605, #2 (April 2004), pp. L133–L136. Bibcode : 2004ApJ...605L.133M
  10. ↑ The Status of White Dwarf Asteroseismology and a Glimpse of the Road Ahead, D. E. Winget, Baltic Astronomy4 (1995), pp. 129–136. Bibcode : 1995BaltA...4..129W
  11. 1 2 "BBC News: Diamond star thrills astronomers". 16 February 2004. Archived from the original on 2007-02-05. Retrieved 2007-02-26.
  12. ↑ Press release Archived 2013-12-25 at the Wayback Machine , 2004, Harvard-Smithsonian Center for Astrophysics.
  13. ↑ "This Valentine's Day, Give The Woman Who Has Everything The Galaxy's Largest Diamond". Center for Astrophysics. Archived from the original on July 6, 2008. Retrieved May 5, 2009.
  14. ↑ "Lucy's in the Sky with Diamonds: Meet the Most Expensive Star Ever Found". Futurism. 12 June 2014. Archived from the original on 11 December 2019. Retrieved 20 May 2019.
  15. ↑ Crystallization of carbon-oxygen mixtures in white dwarfs, J. L. Barrat, J. P. Hansen, and R. Mochkovitch, Astronomy and Astrophysics199, #1–2 (June 1988), pp. L15–L18. Bibcode : 1988A&A...199L..15B
  16. ↑ "Cosmic Backyard". Abstruse Goose. Archived from the original on 2020-07-02. Retrieved 2020-06-28.
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