HD 40307 g
HARPS | |
Orbital characteristics | |
---|---|
0.600 AU (89,800,000 km) | |
Eccentricity | 0.22[1] |
197.8 ± 9.0[1] d | |
Semi-amplitude | 0.95 ± 0.3[1] |
Star | HD 40307 |
Physical characteristics | |
Mean radius | 2.39[2] R🜨 |
Mass | 7.09[2] ME |
Temperature | 277.6[3] |
HD 40307 g is an
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."[4]
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."[4]
See also
- Circumstellar habitable zone
- Extrasolar planet
- List of potentially habitable exoplanets
- Planetary habitability
References
- ^ S2CID 7424216.
- ^ a b "PHL's Exoplanets Catalog - Planetary Habitability Laboratory @ UPR Arecibo". Archived from the original on 2019-05-21. Retrieved 2014-01-09.
- ^ "HEC: Data of Potential Habitable Worlds". University of Puerto Rico at Arecibo (Planetary Habitability Laboratory). November 12, 2012. Archived from the original on December 1, 2017. Retrieved November 16, 2012.
- ^ a b c Wall, Mike (November 7, 2012). "'Super-Earth' Alien Planet May Be Habitable for Life". Space.com. Retrieved November 8, 2012.
- ^ Tate, Karl (November 7, 2012). "Super-Earth Planet: Potentially Habitable Alien World Explained (Infographic)". Space.com. Retrieved November 8, 2012.
- ^ Murrin, Marc (November 8, 2012). "Astronomers discover a potentially habitable Super-Earth HD 40307g (Infographic)". tech-stew.com. Archived from the original on November 10, 2012. Retrieved November 8, 2012.
- S2CID 118531921.
- S2CID 18849636.
- ^ University of Toronto astronomer Ray Jayawardhana, author of Strange New Worlds: The Search for Alien Planets and Life beyond Our Solar System. Paraphrased in Dan Vergano (November 7, 2012). "Habitable zone 'Super Earth' candidate planet detected". USA Today.
External links
- "Super-Earth Discovered in Star's Habitable Zone". Exoplanets. 2017-05-10. Archived from the original on 2012-11-28. Retrieved 2012-11-08.