Kepler-22b
| Extrasolar planet | List of extrasolar planets | |
|---|---|---|
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| Parent star | ||
| Star | Kepler-22 | |
| Constellation | Cygnus | |
| Right ascension | (α) | 19h 16m 52.2s |
| Declination | (δ) | +47° 53′ 4.0″ |
| Apparent magnitude | (mV) | 11.5 (B-band) [1] |
| Distance | 587 ly (180 [2] pc) |
|
| Spectral type | G5V | |
| Mass | (m) | 0.97 M☉ |
| Radius | (r) | 0.98 R☉ |
| Temperature | (T) | 5606 K |
| Orbital elements | ||
| Semimajor axis | (a) | 0.85 AU (127 Gm) |
| Orbital period | (P) | 289.9 [3] d |
| Physical characteristics | ||
| Radius | (r) | 2.4 [4] R⊕ |
| Discovery information | ||
| Discovery date | 2009 (first observed) [5] | |
| Discoverer(s) | Kepler Science Team | |
| Detection method | Transit | |
| Discovery site | Kepler telescope | |
| Discovery status | Published | |
| Other designations | ||
| Database references | ||
| Extrasolar Planets Encyclopaedia |
data | |
| SIMBAD | data | |
Kepler-22b is a confirmed extrasolar planet found to orbit the habitable zone of a Sun-like star.[5] Kepler-22b, a possible super-Earth, was discovered by NASA's Kepler Space Telescope.[6]
Contents[hide] |
[edit] Discovery
The discovery was announced December 5, 2011.[6] The planet was originally discovered on Kepler's third day of science operations in mid-2009. The third transit was detected in late 2010. Additional confirmation data was provided by the Spitzer Space Telescope and ground-based observations. It is 600 light years away from Earth, in orbit around the G-type star Kepler-22.[6][5]
[edit] Composition and structure
Kepler-22b's radius is roughly 2.4 times the radius of Earth (about half that of Neptune). Its mass and surface composition remain unknown,[6][5] with only some very rough estimates established:
It has been estimated that it is probably a "Neptunian" gas planet with a mass of ~35 Earth masses, but in the "best case" it could be an ocean world with only some 10 Earth masses.[7]
The planet is either a super-Earth or a "warm Neptune",[7] depending on its actual mass.[6] Since it is substantially larger than Earth, it is likely to have a different composition. If it is mostly ocean with a small rocky core, Natalie Batalha, one of the scientists on the project, speculated "it's not beyond the realm of possibility that life could exist in such an ocean."[8] This possibility of life has spurred the United States military to fund SETI to perform research on top candidates for extraterrestrial intelligence.[9]
[edit] Surface temperature and composition
The distance from Kepler-22b to its host star Kepler-22 is about 1% less than the distance from Earth to the Sun,[3][10] but the luminosity (light output) of Kepler-22 is about 25% less than that of the Sun.[6] This combination of a shorter distance from the star and a lower stellar luminosity are consistent with a moderate surface temperature. Scientists estimate that in the absence of an atmosphere, the equilibrium temperature would be approximately -11°C. If the atmosphere provides a greenhouse effect similar in magnitude to the one on Earth, the planet would have an average surface temperature of 22 °C (72°F).[6][5]
[edit] See also
[edit] References
- ^ "SIMBAD data for host star". SIMBAD. http://simbad.u-strasbg.fr/simbad/sim-id?Ident=Kepler-22. Retrieved 8 December 2011.
- ^ "Notes for Planet Kepler-22 b". Extrasolar Planet Database. http://exoplanet.eu/planet.php?p1=Kepler-22&p2=b. Retrieved 6 December 2011.
- ^ a b Alien Planet Could Host Life, Discovery.com
- ^ "NASA Telescope Confirms Alien Planet in Habitable Zone", Space.com 12/5/2011
- ^ a b c d e "NASA - NASA's Kepler Confirms Its First Planet in Habitable Zone of Sun-like Star". NASA Press Release. http://www.nasa.gov/centers/ames/news/releases/2011/11-99AR.html. Retrieved 6 December 2011.
- ^ a b c d e f g "BBC News - Kepler 22-b: Earth-like planet confirmed". BBC Online. 5 December 2011. http://www.bbc.co.uk/news/science-environment-16040655. Retrieved 6 December 2011.
- ^ a b Abel Mendez Torres (2011-12-08). "Updates on Exoplanets during the First Kepler Science Conference". Planetary Habitability Laboratory at UPR Arecibo. http://phl.upr.edu/library/notes/updatesonexoplanetsduringthefirstkeplerscienceconference.
- ^ Borenstein, Seth (5 December 2011). "Planet in sweet spot of Goldilocks zone for life". Associated Press. http://hosted2.ap.org/APDEFAULT/3d281c11a96b4ad082fe88aa0db04305/Article_2011-12-06-Alien%20Planet/id-6e919895b31c4012a1df1b4f664fb63e. Retrieved 6 December 2011.
- ^ Ian O'Neill (2011-12-05). "SETI to Hunt for Aliens on Kepler's Worlds". Discovery News. http://news.discovery.com/space/seti-to-hunt-for-aliens-on-keplers-worlds.html.
- ^ NASA - NASA's Kepler Mission Confirms Its First Planet in Habitable Zone of Sun-like Star
[edit] External links
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Wikimedia Commons has media related to: Kepler-22 b |
- "NASA Telescope Confirms Alien Planet in Habitable Zone" (Space.com)
- "Kepler 22-b: Earth-like planet confirmed" (BBC)
- "NASA's Kepler Confirms Its First Planet In Habitable Zone" (NASA)
- "Kepler discoveries: Kepler-22b: 'a yearly orbit of 289 days'" (NASA)
- "View of Kepler 22-b Sky Location" (Worldwide Telescope)
- "The Habitable Exoplanets Catalog" (PHL/UPR Arecibo)
- Preprint of discovery paper - Accepted to Astrophysical Journal
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