.png) Approximate size comparison of Kepler-442b (left) with Earth | |
| Discovery | |
|---|---|
| Discovered by | Kepler spacecraft |
| Discovery date | 6 January 2015[1][2] |
| Transit | |
| Orbital characteristics | |
| 0.409+0.209 −0.060 AU | |
| Eccentricity | 0.04+0.08 −0.04[1] |
| 112.3053+0.0024 −0.0028[1] d | |
| Inclination | 89.94+0.06 −0.12[1] |
| Star | Kepler-442 (KOI-4742) |
| Physical characteristics | |
| 1.34+0.11 −0.18[1] R🜨 | |
| Mass | 2.3+5.9 −1.3[3] ME |
| Temperature | Teq: 233 K (−40 °C; −40 °F) |
Kepler-442b[1][4][5] (also known by its Kepler object of interest designation KOI-4742.01) is a confirmed near-Earth-sized exoplanet, likely rocky, orbiting within the habitable zone of the K-type main-sequence star[6] Kepler-442, about 1,206 light-years (370 pc) from Earth in the constellation of Lyra.[4][5]
The planet orbits its host star at a distance of about 0.409 AU (61.2 million km; 38.0 million mi) with an orbital period of roughly 112.3 days. It has a mass of around 2.3 and has a radius of about 1.34 times that of Earth. It is one of the more promising candidates for potential habitability, as its parent star is at least 40% less massive than the Sun – thus, it can have a lifespan of about 30 billion years.[7]
The planet was discovered by NASA's Kepler spacecraft using the transit method, in which it measures the dimming effect that a planet causes as it crosses in front of its star. NASA announced the confirmation of the exoplanet on 6 January 2015.[5]
- ^ a b c d e f Torres, Guillermo; Kipping, David M.; Fressin, Francois; Caldwell, Douglas A.; Twicken, Joseph D.; Ballard, Sarah; Batalha, Natalie M.; Bryson, Stephen T.; Ciardi, David R.; Henze, Christopher E.; Howell, Steve B.; Isaacson, Howard T.; Jenkins, Jon M.; Muirhead, Philip S.; Newton, Elisabeth R.; Petigura, Erik A.; Barclay, Thomas; Borucki, William J.; Crepp, Justin R.; Everett, Mark E.; Horch, Elliott P.; Howard, Andrew W.; Kolbl, Rea; Marcy, Geoffrey W.; McCauliff, Sean; Quintana, Elisa V. (2015). "Validation of Twelve Small Kepler Transiting Planets in the Habitable Zone". The Astrophysical Journal. 800 (2): 99. arXiv:1501.01101. Bibcode:2015ApJ...800...99T. doi:10.1088/0004-637X/800/2/99. S2CID 8512655.
- ^ Staff (2015). "Planet Kepler-442 b". Extrasolar Planets Encyclopaedia. Retrieved 11 January 2015.
- ^ Cite error: The named reference
UPR-Catalogwas invoked but never defined (see the help page). - ^ a b Sample, Ian (7 January 2015). "Kepler 438b: Most Earth-like planet ever discovered could be home for alien life". The Guardian. Retrieved 7 January 2015.
- ^ a b c Clavin, Whitney; Chou, Felicia; Johnson, Michele (6 January 2015). "NASA's Kepler Marks 1,000th Exoplanet Discovery, Uncovers More Small Worlds in Habitable Zones". NASA. Retrieved 6 January 2015.
- ^ Gilster, Paul (6 January 2015). "AAS: 8 New Planets in Habitable Zone". Centauri-dreams.org. Retrieved 9 January 2015.
- ^ Cite error: The named reference
KTypePosLifewas invoked but never defined (see the help page).