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*[[Extraterrestrial liquid water]]
*[[Extraterrestrial liquid water]]
*[[24 Themis]], the first Solar System asteroid detected having liquid water
*[[24 Themis]], the first Solar System asteroid detected having liquid water

==External links==
*[http://notice.usa.gov/ GD 61 at NASA website] (not accessible due to [[United States federal government shutdown of 2013|United States federal government shutdown]])


{{Stars of Perseus}}
{{Stars of Perseus}}

Revision as of 12:24, 20 October 2013

GD 61
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Perseus
Right ascension 04h 38m 39.39s [1]
Declination +41° 09′ 32.5″ [1]
Apparent magnitude (V) 14.8 [2]
Spectral typeDBZ [1]
Other designations
2MASS J04383938+4109325, EGGR 315, WD 0435+41, Lan 542
File:Artist's view of watery asteroid in white dwarf star system GD 61.jpg
Artist's view of watery asteroid, in the GD 61 system (NASA)

GD 61 is a white dwarf with a planetary system 150 light-years from Earth in the constellation Perseus.[3] Originally thought to have been a main sequence star of spectral type A0V with around triple the mass of our sun, it has aged and passed through a red giant phase, leaving a dense hot remnant that has around 70% of our Sun's mass and a surface temperature of 17280 K. It is thought to be around 600 million years old, including both its life as a main sequence star and white dwarf stellar remnant.[4] It has an apparent magnitude of 14.8.[2] 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.[5]

An asteroid in the system was detected in 2013 that contains water, the first detection of solid or liquid water on an extrasolar body. The asteroid, the first extrasolar asteroid detected, is 26% water by mass, close to the water content of Ceres. This evidence suggests that a planet, with a rocky surface similar to Earth's, may have existed in the past, with the asteroid thus being an artifact from this period, now possibly part of a debris field from the hypothetical planet's breakup. Such a planet would have had both a rocky surface and water, two key ingredients for life.[6][7][8] The elements magnesium, silicon and iron and oxygen were detected, all components of rocky planets, however the levels of oxygen were much higher than what could be accounted for. The lack of associated carbon left only one candidate for the oxygen excess—water.[7]

Detection

Data from NASA's Hubble and FUSE telescopes, and from the Keck Observatory in Hawaii, were used to detect and observe the asteroid.

References

  1. ^ a b c "GD 61 -- White Dwarf". SIMBAD Astronomical Database. Centre de Données astronomiques de Strasbourg. Retrieved 20 October 2013.
  2. ^ a b S. Xu (许偲艺) and M. Jura (2012). The Astrophysical Journal. 745 (1): 88–102. Bibcode:2012ApJ...745...88X. doi:10.1088/0004-637X/745/1/88. {{cite journal}}: Missing or empty |title= (help)
  3. ^ Rosen, Meghan (13 October 2013). "Water seen in rubble around star". ScienceNews. Retrieved 14 October 2013.
  4. ^ Farihi, J.; Brinkworth, C. S.; Gänsicke, B. T.; Marsh, T. R.; Girven, J.; Hoard, D. W.; Klein, B.; Koester, D. "Possible Signs of Water and Differentiation in a Rocky Exoplanetary Body". The Astrophysical Journal Letters. 728 (1): L8–L13. Bibcode:2011ApJ...728L...8F. doi:10.1088/2041-8205/728/1/L8.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  5. ^ Giclas, Henry L.; Burnham, Robert; Thomas, Norman Gene (1965). "A list of white dwarf suspects I : special objects of small proper motion from the Lowell survey" (PDF). Bulletin / Lowell Observatory. 6 (6): 155–64. Bibcode:1965LowOB...6..155G.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  6. ^ Sterling, Nate (October 12, 2013). "Scientists discover water-rich asteroid orbiting dead star GD 61 outside our solar system". Pentagon Post. Retrieved 2013-10-12.
  7. ^ a b "Watery asteroid discovered in dying star points to habitable exoplanets". Phys.org. October 10, 2013. Retrieved 2013-10-12.
  8. ^ Mack, Eric (2011-10-17). "Newly spotted wet asteroids point to far-flung Earth-like planets | Crave - CNET". News.cnet.com. Retrieved 2013-10-12.

See also

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