Kepler-438b

Kepler-438b[1][2][3]
Exoplanet List of exoplanets

Approximate size comparison of Kepler-438b (right) with Earth
Parent star
Star Kepler-438
Constellation Lyra[2]
Right ascension (α) 18h 46m 35.000s
Declination (δ) +41° 57′ 3.93″
Apparent magnitude (mV) 14.467
Distance470;[2] 475[1] ly
(145 pc)
Mass (m) 0.540 M☉
Radius (r) 0.520 R☉
Temperature (T) 3748 K
Metallicity [Fe/H] 0.160
Age 4.4+0.8
−0.7[3] Gyr
Physical characteristics
Radius(r)1.120 R⊕
Stellar flux(F⊙)1.40+0.67
−0.77 ⊕
Temperature (T) 276 K (3 °C; 37 °F)
Orbital elements
Semi-major axis(a) 0.16600 AU
Eccentricity (e) 0.03+0.01
−0.03[3]
Orbital period(P) 35.23319000 d
Inclination (i) 89.860°
Discovery information
Discovery date 2015[4]
Discoverer(s)
Discovery method Transit
Discovery site Kepler Space Observatory
Discovery status Published refereed article
Other designations
KOI-3284.01; Kepler-438 b; KOI-3284 b; K03284.01; WISE J184634.98+415704.0 b; KIC 6497146 b; 2MASS J18463499+4157039 b
Database references
Extrasolar Planets
Encyclopaedia		data
SIMBADdata
Exoplanet Archivedata
Open Exoplanet Cataloguedata

Kepler-438b (also known by its Kepler Object of Interest designation KOI-3284.01) is a confirmed near-Earth-sized exoplanet, likely rocky, orbiting within the habitable zone of the red dwarf[5] Kepler-438, about 470 light-years (145 pc) from Earth in the constellation Lyra.[1][2] The planet was discovered by NASA's Kepler spacecraft using the transit method, in which the dimming effect that a planet causes as it crosses in front of its star is measured. NASA announced the confirmation of the exoplanet on 6 January 2015.[1] Although it is not habitable, as of June 2015, it is the most Earth-like exoplanet.[6]

Kepler-438b is 475 light years from Earth, so travelling there is presently impossible. The German-designed Helios probes, notable for having set the current speed record among spacecraft at 252,792 km/h, would take some two million years to travel to Kepler-438b.[7]

Basic data

Kepler-438b is a near-Earth-sized exoplanet with a radius 1.12 times that of Earth. The planet orbits the red dwarf[5] Kepler-438, a star considerably smaller and cooler than the Sun, once every 35.2 days.[1][2]

Habitability

The planet was announced as orbiting within the habitable zone of Kepler-438, a region where liquid water could exist on the surface of the planet. In the Earth Similarity Index (ESI), which measures how similar are planets to Earth as to physics and chemistry, with 1.00 being the most similar, Kepler-438b has an index of 0.88, the highest known to date, making it currently the most Earth-like planet.[1][2] However it has been found that this planet is subjected to superflare activity from its parent star every 100 days, much more violent storms than the stellar flares emitted by the Sun and which would be capable of sterilizing life on Earth.[8]

Researchers at the University of Warwick say that Kepler-438b is not habitable after all due to the large amount of radiation it receives.[9] The question of what makes a planet habitable is much more complex than having a planet located at the right distance from its host star so that water can be liquid on its surface: various geophysical and geodynamical aspects, the radiation, and the host stars plasma environment can influence the evolution of planets and life, if it originated.[10]

Notable Exoplanets – Kepler Space Telescope
Confirmed small exoplanets in habitable zones.
(Kepler-62e, Kepler-62f, Kepler-186f, Kepler-296e, Kepler-296f, Kepler-438b, Kepler-440b, Kepler-442b)
(Kepler Space Telescope; 6 January 2015).[1]

See also

References

  1. 1 2 3 4 5 6 7 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.
  2. 1 2 3 4 5 6 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.
  3. 1 2 3 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". arXiv:1501.01101 [astro-ph.EP].
  4. ↑ Staff (2015). "Planet Kepler-438 b". The Extrasolar Planets Encyclopaedia. Retrieved 11 January 2015.
  5. 1 2 Gilster, Paul (6 January 2015). "AAS: 8 New Planets in Habitable Zone". Centauri-dreams.org. Retrieved 9 January 2015.
  6. ↑ "10 Real Planets That Are Stranger Than Science Fiction". Retrieved 2015-06-13.
  7. ↑ Alien earth 'could support life', but what is Kepler 438b like?
  8. ↑ Perkins, Sid (2015). "Earth-like planet may be not so hospitable after all, thanks to blasts of radiation". Science. doi:10.1126/science.aad7455. ISSN 0036-8075.
  9. ↑ 'Earth-like' Exoplanet Likely Not Habitable
  10. ↑ Lammer, H.; Bredehöft, J. H.; Coustenis, A.; Khodachenko, M. L.; et al. (2009). "What makes a planet habitable?" (PDF). The Astronomy and Astrophysics Review 17: 181–249. Bibcode:2009A&ARv..17..181L. doi:10.1007/s00159-009-0019-z. Retrieved 2016-05-03.

External links

Wikimedia Commons has media related to Kepler Mission.
Preceded by
Gliese 667 Cc		 Highest ESI for an exoplanet
2015 — present 		Succeeded by
none

Coordinates: 18h 46m 35.000s, +41° 57′ 03.93″

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