GD 362

Last updated
GD 362
Observation data
Epoch J2000.0        Equinox J2000.0 (ICRS)
Constellation Hercules [1]
Right ascension 17h 31m 34.33s [2]
Declination +37° 05 20.6 [2]
Apparent magnitude  (V)16.23 [2]
Characteristics
Spectral type DAZB [3]
B−V color index 0.2 [4]
Astrometry
Proper motion (μ)RA: 27 [2]   mas/yr
Dec.: -223 [2]   mas/yr
Distance ~150 [5]   ly
(50.6 [6]   pc)
Details
Mass 0.73±0.02 [7]   M
Surface gravity (log g)8.24±0.04 [7]   cgs
Temperature 10540±200 [7]   K
Other designations
G 204-14, NLTT 44986, WD 1729+371, EGGR 545, 2MASS  J17313433+3705209, PG 1729+371 [3]
Database references
SIMBAD data

GD 362 is a white dwarf approximately 150 light years from Earth. [5] In 2004, spectroscopic observations showed that it had a relatively high concentration of metals in its atmosphere. Since the high gravitational field of white dwarfs quickly forces heavy elements to settle towards the bottom of the atmosphere, this meant that the atmosphere was being polluted by an external source. [4] In 2005, infrared photometric observations suggested that it was surrounded by a ring of dust with size comparable to the rings of Saturn, providing an explanation for this pollution. [8]

In 2006, Benjamin Zuckerman, Michael Jura and other astronomers used the Keck telescope to obtain high-resolution spectra of GD 362 which showed that heavy elements in the star's atmosphere occurred in concentrations similar to those in the Earth-Moon system. [7] The group concluded that a possible origin for GD 362's dust ring and atmospheric pollutants was that a rocky asteroid about 200 km in diameter was disintegrated by tidal effects between 100,000 and 1 million years ago. If this was the origin, the spectra indicate that the asteroid should have had composition similar to the Earth's crust, suggesting that the star might have had an Earth-like planet before it entered its red giant phase. [5] [7] [9]

GD 362 has been a white dwarf for approximately 900 million years. [10]

Related Research Articles

<span class="mw-page-title-main">Stellar classification</span> Classification of stars based on their spectral characteristics

In astronomy, stellar classification is the classification of stars based on their spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a prism or diffraction grating into a spectrum exhibiting the rainbow of colors interspersed with spectral lines. Each line indicates a particular chemical element or molecule, with the line strength indicating the abundance of that element. The strengths of the different spectral lines vary mainly due to the temperature of the photosphere, although in some cases there are true abundance differences. The spectral class of a star is a short code primarily summarizing the ionization state, giving an objective measure of the photosphere's temperature.

<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 faint 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">Brown dwarf</span> Type of substellar object larger than a planet

Brown dwarfs are substellar objects that are not massive enough to sustain nuclear fusion of ordinary hydrogen (1H) into helium in their cores, unlike a main-sequence star. Instead, they have a mass between the most massive gas giant planets and the least massive stars, approximately 13 to 80 times that of Jupiter (MJ). However, they can fuse deuterium (2H), and the most massive ones can fuse lithium (7Li).

<span class="mw-page-title-main">Ross 128</span> Small star in constellation of Virgo

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<span class="mw-page-title-main">Van Maanen 2</span> White dwarf

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<span class="mw-page-title-main">BD+20°307</span> Star in the constellation Aries

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<span class="mw-page-title-main">HR 4796</span> Binary star system in the constellation Centaurus

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HR 8799 is a roughly 30 million-year-old main-sequence star located 133.3 light-years away from Earth in the constellation of Pegasus. It has roughly 1.5 times the Sun's mass and 4.9 times its luminosity. It is part of a system that also contains a debris disk and at least four massive planets. Those planets, along with Fomalhaut b, were the first exoplanets whose orbital motion was confirmed by direct imaging. The star is a Gamma Doradus variable: its luminosity changes because of non-radial pulsations of its surface. The star is also classified as a Lambda Boötis star, which means its surface layers are depleted in iron peak elements. It is the only known star which is simultaneously a Gamma Doradus variable, a Lambda Boötis type, and a Vega-like star.

GD 40 is a white dwarf in the constellation Cetus. It is located about 212 light-years away from the Sun. The star's spectrum has been found to show traces of external of metal contamination due to disruption of an extrasolar dwarf planet or an asteroid. The disrupted object should have had roughly the same mass of the Solar System asteroid 3 Juno.

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

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GD 61 is a white dwarf with a planetary system located 150 light-years from Earth in the constellation Perseus. It is thought to have been a main-sequence star of spectral type A0V with around three times the mass of the Sun that has aged and passed through a red-giant phase, leaving a dense, hot remnant that has around 70% of the Sun's mass and a surface temperature of 17,280 K. It is thought to be around 600 million years old, including both its life as a main-sequence star and as a white dwarf. It has an apparent magnitude of 14.8. GD 61 was first noted as a potential degenerate star in 1965, in a survey of white-dwarf suspects by astronomers from the Lowell Observatory in Arizona.

<span class="mw-page-title-main">U Monocerotis</span> Variable star system in the constellation Monoceros

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<span class="mw-page-title-main">LSPM J0207+3331</span> Star in the constellation Taurus

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WD J2356−209 is a white dwarf star located 65 pc away from the Earth. It is a very faint white dwarf, with an apparent visual magnitude of 21.03. Its visible spectrum is dominated by a broad absorption feature that has been attributed to pressure-broadened sodium D lines. The presence of this sodium absorption feature and the detection of spectral lines from other heavy elements indicate that the photosphere of WD J2356−209 has been polluted by a recent rocky debris accretion episode. A detailed analysis of the spectrum of WD J2356−209 shows that the accreted planetesimal was abnormally sodium-rich, containing up to ten times more sodium than calcium. With an effective temperature of 4040 K, WD J2356−209 is the coolest metal-polluted white dwarf observed to date.

<span class="mw-page-title-main">WD 0145+234</span> White dwarf in the constellation Aries

WD 0145+234 is a white dwarf star approximately 95 ly (29 pc) from Earth in the constellation of Aries that has been associated with studies suggesting that a very large exoasteroid near the star was substantially disrupted, resulting in a considerable amount of dust and debris around the star. Alternatively the outburst around WD 0145+234 is explained with ongoing collisions between planetesimals inside the dusty debris disk around the white dwarf.

References

  1. Constellation boundaries, CDS. Accessed on line October 4, 2007.
  2. 1 2 3 4 5 Improved Astrometry and Photometry for the Luyten Catalog. II. Faint Stars and the Revised Catalog, Samir Salim and Andrew Gould, Astrophysical Journal582, #2 (January 2003), pp. 10111031; CDS ID J/ApJ/582/1011. Entry for NLTT 44986. Accessed on line October 4, 2007.
  3. 1 2 "GD 362". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved October 4, 2007.
  4. 1 2 Discovery of a Cool, Massive, and Metal-rich DAZ White Dwarf, A. Gianninas, P. Dufour, and P. Bergeron, The Astrophysical Journal617, #1 (December 2004), pp. L57–L60.
  5. 1 2 3 Dunham, Will (2007-08-16). "Burned-out star harbors signs of Earthlike planets". Reuters . Retrieved 2007-08-17.
  6. Direct Distance Measurement to the Dusty White Dwarf GD 362, Mukremin Kilic, John R. Thorstensen, and D. Koester, ApJL,689,1
  7. 1 2 3 4 5 Zuckerman; et al. (2007). "The Chemical Composition of an Extrasolar Minor Planet". The Astrophysical Journal. 671 (1): 872–877. arXiv: 0708.0198 . Bibcode:2007ApJ...671..872Z. doi:10.1086/522223. S2CID   9631635.
  8. A Dusty Disk around GD 362, a White Dwarf with a Uniquely High Photospheric Metal Abundance, E.E. Becklin, J. Farihi, M. Jura, Inseok Song, A. J. Weinberger, and B. Zuckerman, The Astrophysical Journal632, #2 (October 2005), pp. L119–L122.
  9. "GD 362 Shows Signs It Had An Earthlike Planet". Scientificblogging.com. 2007-08-16. Archived from the original on 2013-02-02. Retrieved 2007-08-17.
  10. "Stars with Exoplanets: GD 362" . Retrieved 2007-08-17.