HD 40307 g explained

HD 40307 g
Discoverer:Mikko Tuomi et al.
Discovery Site:La Silla Observatory, Chile
Discovered:October 28, 2012
Apsis:astron
Semimajor:0.6AU
Eccentricity:0.22
Period:197.8 ± 9.0 d
Semi-Amplitude:0.95 ± 0.3
Mean Radius:2.39[1]
Mass:7.09
Single Temperature:277.6[2]

HD 40307 g is an exoplanet candidate suspected to be orbiting in the habitable zone of HD 40307. It is located 42 light-years away in the direction of the southern constellation Pictor. The planet was discovered by the radial velocity method, using the European Southern Observatory's HARPS apparatus[3] [4] [5] by a team of astronomers led by Mikko Tuomi at the University of Hertfordshire and Guillem Anglada-Escude of the University of Göttingen, Germany.[6]

The existence of the planet was disputed in 2015, as more Doppler spectroscopy data has become available.[7]

Planetary characteristics

The codiscoverer Hugh Jones, of the University of Hertfordshire in England, surmised: "The longer orbit of the new planet means that its climate and atmosphere may be just right to support life."

However, another astronomer, Rory Barnes of the University of Washington, had already studied the orbits of the planets b, c, and d. First, Barnes had presumed b to take on too much tidal heating for it to be terrestrial, instead predicting a "mini-Neptune". He thought that b, c, and d had all migrated inward,[8] which extrapolates to e and f as well, which are further out, but not by much. It is possible that HD 40307 g has also migrated into where it is now. The discoverers of HD 40307 g did not try to refute Barnes, on the nature of b and its extrapolation to the other planets. The composition of g is unsettled.[9] Lead author Mikko Tuomi, also of the University of Hertfordshire, stated"If I had to guess, I would say 50-50 ... But the truth at the moment is that we simply do not know whether the planet is a large Earth or a small, warm Neptune without a solid surface."

See also

External links

Notes and References

  1. Web site: PHL's Exoplanets Catalog - Planetary Habitability Laboratory @ UPR Arecibo . 2014-01-09 . 2019-05-21 . https://web.archive.org/web/20190521010035/http://phl.upr.edu/projects/habitable-exoplanets-catalog/data/database . dead .
  2. Web site: HEC: Data of Potential Habitable Worlds . November 12, 2012 . University of Puerto Rico at Arecibo (Planetary Habitability Laboratory) . November 16, 2012 . December 1, 2017 . https://web.archive.org/web/20171201032102/http://phl.upr.edu/projects/habitable-exoplanets-catalog/data . dead .
  3. 10.1051/0004-6361/201220268 . Tuomi . Mikko . Anglada-Escudé . Guillem . Gerlach . Enrico . Jones . Hugh R. A. . Reiners . Ansgar . Rivera . Eugenio J. . Vogt . Steven S. . Butler . R. Paul . Habitable-zone super-Earth candidate in a six-planet system around the K2.5V star HD 40307 . Astronomy & Astrophysics . 17 December 2012 . 549 . A48 . 1211.1617 . 2013A&A...549A..48T . 7424216 .
  4. News: Wall . Mike . 'Super-Earth' Alien Planet May Be Habitable for Life . November 7, 2012 . . November 8, 2012 .
  5. News: Tate . Karl . Super-Earth Planet: Potentially Habitable Alien World Explained (Infographic) . November 7, 2012 . . November 8, 2012 .
  6. Web site: Murrin . Marc . Astronomers discover a potentially habitable Super-Earth HD 40307g (Infographic) . November 8, 2012 . . November 8, 2012 . https://web.archive.org/web/20121110203130/http://www.tech-stew.com/post/2012/11/08/Astronomers-discover-a-potentially-habitable-Super-Earth-HD40307g.aspx . November 10, 2012 . dead .
  7. The HARPS search for southern extra-solar planets. XXXVIII. Bayesian re-analysis of three systems. New super-Earths, unconfirmed signals, and magnetic cycles . Díaz . R. F. . Ségransan . D. . Udry . S. . Lovis . C. . Pepe . F. . Dumusque . X. . Marmier . M. . Alonso . R. . Benz . W. . Bouchy . F. . Coffinet . A. . Collier Cameron . A. . Deleuil . M. . Figueira . P. . Gillon . M. . Lo Curto . G. . Mayor . M. . Mordasini . C. . Motalebi . F. . Moutou . C. . Pollacco . D. . Pompei . E. . Queloz . D. . Santos . N. . Wyttenbach . A. . 1 . Astronomy and Astrophysics . 585 . A134 . 2016 . 1510.06446 . 2016A&A...585A.134D . 10.1051/0004-6361/201526729 . 118531921 .
  8. 0901.1698. Barnes, R.. Jackson, B.. Raymond, S.. West, A.. Greenberg, R.. The HD 40307 Planetary System: Super-Earths or Mini-Neptunes?. The Astrophysical Journal. 2009. 10.1088/0004-637X/695/2/1006. 695. 2. 1006–1011. 2009ApJ...695.1006B. 18849636 .
  9. University of Toronto astronomer Ray Jayawardhana, author of Strange New Worlds: The Search for Alien Planets and Life beyond Our Solar System. Paraphrased in Web site: Habitable zone 'Super Earth' candidate planet detected. Dan Vergano . USA Today. November 7, 2012.

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "HD 40307 g".

Except where otherwise indicated, Everything.Explained.Today is © Copyright 2009-2024, A B Cryer, All Rights Reserved. Cookie policy.