Wikipedia

Nemesis (star)

hypothetical star orbiting the Sun, responsible of extinction events

Nemesis is a hypothetical red dwarf[1] or brown dwarf,[2] first thought in 1984[3] to be orbiting the Sun at a distance of about 95,000 AU (1.5 light-years),[2] past the Oort cloud, to explain a cycle of mass extinctions in the geological record, which look like they happen every 26 million years.[2][4] In a 2017 paper, Sarah Sadavoy and Steven Stahler said that the Sun was probably part of a binary system when it formed, making them suggest "there probably was a Nemesis, a long time ago".[5][6] This star would have separated from this binary system more than four billion years ago, meaning it could not be what made the cycle of mass extinctions.[7]

Later, geologists found there was a cycle of extinctions, but it was twice as long.[8] However, in 2011, scientists checked at craters and found there was no pattern.[9]

There were many attempts to find Nemesis. The Infared Astronomical Satellite, launched in the 1980s, was not able to find it. The 2MASS astronomical survey, which ran from 1997 to 2001, did not see another star or brown dwarf in the Solar System. Using newer and more powerful infrared telescope technology that can find brown dwarfs as cold as 150 kelvins out to a distance of 10 light-years from the Sun, the Wide-field Infrared Survey Explorer (WISE survey) has not found Nemesis.[10][11][12][13][14][15][16]

References

change
  1. ↑ Leader-Post, "Scientists claim killer star exists", 22 Feb 1984, Page B6, Associated Press
  2. ↑ 2.0 2.1 2.2 Leslie Mullen (11 March 2010). "Getting WISE About Nemesis". Astrobiology Magazine (Cosmic Evolution). Archived from the original on 14 March 2010. Retrieved 2010-05-15.{{cite web}}: CS1 maint: unfit URL (link)
  3. ↑ M. Davis, P. Hut, and R. Muller, “Extinction of species by periodic comet showers”, Nature 308, 715 (1984).
  4. ↑ Raup, D.M.; Sepkoski, J.J. (1 February 1984). "Periodicity of Extinctions in the Geologic Past" (PDF). Proceedings of the National Academy of Sciences. 81 (3): 801–805. Bibcode:1984PNAS...81..801R. doi:10.1073/pnas.81.3.801. PMC 344925. PMID 6583680. Retrieved 30 April 2007.
  5. ↑ "New evidence that all stars are born in pairs". Berkeley News. 2017-06-13. Retrieved 2018-06-19.
  6. ↑ Sadavoy, Sarah I.; Stahler, Steven W. (2017-05-03). "Embedded binaries and their dense cores". Monthly Notices of the Royal Astronomical Society. 469 (4): 3881–3900. arXiv:1705.00049. Bibcode:2017MNRAS.469.3881S. doi:10.1093/mnras/stx1061. ISSN 0035-8711. S2CID 119341787.
  7. ↑ Levine, David (2018-06-19). "All stars in the universe may form in pairs — but we can't find the sun's missing 'Nemesis'". Business Insider. Retrieved 2018-06-19.
  8. ↑ Melott, A.L.; Bambach, R.K. (2010). "Nemesis Reconsidered". Monthly Notices of the Royal Astronomical Society Letters. 407 (1): L99–L102. arXiv:1007.0437. Bibcode:2010MNRAS.407L..99M. doi:10.1111/j.1745-3933.2010.00913.x. S2CID 7911150.
  9. ↑ "Nemesis is a myth". Max Planck. August 1, 2011. Retrieved 2011-10-07.
  10. ↑ Kirkpatrick, J. Davy; Cushing, Michael C.; Gelino, Christopher R.; Griffith, Roger L.; et al. (2011). "The First Hundred Brown Dwarfs Discovered by the Wide-field Infrared Survey Explorer (WISE)". The Astrophysical Journal Supplement. 197 (2): 19. arXiv:1108.4677v1. Bibcode:2011ApJS..197...19K. doi:10.1088/0067-0049/197/2/19. S2CID 16850733.
  11. ↑ David Morrison (October 17, 2012). "The idea has been disproved by several infrared sky surveys, most recently the WISE mission". NASA Ask An Astrobiologist. Archived from the original on October 23, 2012. Retrieved 2012-10-18.
  12. ↑ David Morrison (August 2, 2011). "Scientists today no longer think an object like Nemesis could exist". NASA Ask An Astrobiologist. Archived from the original on December 13, 2012. Retrieved 2011-10-22.
  13. ↑ David Morrison (November 25, 2010). "this hypothetical Nemesis does not exist". NASA Ask An Astrobiologist. Archived from the original on December 13, 2012. Retrieved 2011-11-09.
  14. ↑ "NASA's WISE Survey Finds Thousands of New Stars, But No 'Planet X'". Nasa JPL. 2014-03-07. Archived from the original on 2014-03-12. Retrieved 2014-03-15.
  15. ↑ "Science: Brown Dwarfs". WISE/NASA. Retrieved 2007-12-28.
  16. ↑ Leslie Mullen (Astrobiology Magazine) (11 March 2010). "Sun's Nemesis Pelted Earth with Comets, Study Suggests". Space.com. Retrieved 2010-08-22.


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