Kepler-37b

Kepler-37b
	NASA Artist Impression of Kepler-37b
Discovery
Discovery date	February 20, 2013
Detection method	Transit
Orbital characteristics
Semi-major axis	0.1003 AU
Orbital period (sidereal)	13.367308 d
Inclination	88.63°
Physical characteristics
Mean radius	0.303 R⊕ ; 1930 km
Mass	>0.01 M⊕; <6 M⊕
Temperature	700 K

Kepler-37b is an extrasolar planet (exoplanet) orbiting Kepler-37 in the constellation Lyra.^[7] As of February 2013^[update] it is the smallest planet discovered around a main-sequence star, with a radius slightly greater than that of the Moon.^[8] The measurements do not constrain its mass, but masses above a few times that of the Moon give unphysically high densities.^[5]

Discovery

Kepler-37b, along with two other planets, Kepler-37c and Kepler-37d, were discovered by the Kepler space telescope, which observes stellar transits.^[1]^[6] After observing transits of Kepler-37b, astronomers had to compare it with the size of the parent star.

The size of the star was obtained using asteroseismology;^{[clarification needed]}^[9] Kepler-37 is currently the smallest star to be studied using this process.^[6] This allowed the size of Kepler-37b to be determined "with extreme accuracy".^[6]

To date, Kepler-37b is the smallest planet discovered around a main-sequence star^[b] outside the Solar System.^[8] Detection of Kepler-37b was possible due to its short orbital period, relative brightness, and low activity of its host star, allowing brightness data to average out quickly.^[10] The discovery of Kepler-37b has led Jack Lissauer, a scientist at NASA's Ames Research Center, to conjecture that "such little planets are common".^[6]

Orbit

Kepler-37b orbits its parent star at a distance of about 15 million kilometers (9.3 million miles), with a period of roughly 13 days.^[8] The outer two planets in the system have orbital periods^[1]^[2] within one percent of the 8:5 and 3:1 resonances with Kepler-37b's period.

Physical properties

Kepler-37b is located approximately 210 light-years from Earth.^[11] It is slightly larger than the Moon, with a diameter of about 3,900 kilometres (2,400 mi).^[9] NASA states that it probably has no atmosphere and cannot support life.^[6] Furthermore, it is most likely composed of rocky materials.^[6] Because it is so close to its star (Mercury is more than three times as far from the Sun), Kepler-37b's mean temperature is estimated to be around 425 °C (800 °F).^[6]

Notes

^ Masses more than a few times that of the Moon result in unphysically high densities.
^ The pulsar planet PSR B1257+12 A has a comparable mass. The actual size of PSR B1257+12 A is unknown, but is likely comparable to Kepler-37b.

References

^ ^a ^b ^c ^d ^e Barclay, T.; Rowe, J. F.; Lissauer, J. J.; Huber, D.; Fressin, F.; Howell, S. B.; Bryson, S. T.; Chaplin, W. J.; Désert, J. M. (2013-02-20). "A sub-Mercury-sized exoplanet". Nature. 494 (7438): 452–4. arXiv:1305.5587. Bibcode:2013Natur.494..452B. doi:10.1038/nature11914. ISSN 0028-0836. PMID 23426260. Retrieved 2013-02-21.
^ ^a ^b ^c ^d "Kepler-37 System". kepler.nasa.gov. Retrieved February 21, 2013.
^ http://kepler.nasa.gov/news/index.cfm?FuseAction=ShowNews&NewsID=256
^ http://exoplanet.eu/catalog/kepler-37b/
^ ^a ^b [1]
^ ^a ^b ^c ^d ^e ^f ^g ^h "NASA's Kepler Mission Discovers Tiny Planet System". NASA. February 20, 2013. Retrieved February 21, 2013.
^ Smallest Alien Planet Kepler-37b Explained (Infographic)
^ ^a ^b ^c "Tiniest Planet Yet Discovered by NASA Outside our Solar System". scienceworldreport.com. February 21, 2013. Retrieved February 21, 2013.
^ ^a ^b "Astronomers Find the Tiniest Exoplanet Yet". Slate. February 20, 2013. Retrieved February 21, 2013.
^ Centauri Dreams - Small Planets Confirm Kepler’s Capabilities
^ "NASA, using Kepler space telescope, finds smallest planet yet". Los Angeles Times. February 20, 2013. Retrieved February 21, 2013.

Templates

Records
Preceded by PSR B1257+12 A	Least massive exoplanet^{[citation needed]} 2013—	Succeeded by current
Preceded by Kepler-42 d	Smallest-volume exoplanet 2013—	Succeeded by current

[6] Masses more than a few times that of the Moon result in unphysically high densities.

[11] The pulsar planet PSR B1257+12 A has a comparable mass. The actual size of PSR B1257+12 A is unknown, but is likely comparable to Kepler-37b.

[nature-1] Barclay, T.; Rowe, J. F.; Lissauer, J. J.; Huber, D.; Fressin, F.; Howell, S. B.; Bryson, S. T.; Chaplin, W. J.; Désert, J. M. (2013-02-20). "A sub-Mercury-sized exoplanet". Nature. 494 (7438): 452–4. arXiv:1305.5587. Bibcode:2013Natur.494..452B. doi:10.1038/nature11914. ISSN 0028-0836. PMID 23426260. Retrieved 2013-02-21.

[keplernasa-2] "Kepler-37 System". kepler.nasa.gov. Retrieved February 21, 2013.

[3] ttp://kepler.nasa.gov/news/index.cfm?FuseAction=ShowNews&NewsID=256

[exoplanetcatalog-4] ttp://exoplanet.eu/catalog/kepler-37b/

[smallKeplerMRO-5] [1]

[NASA-7] ^ ^a ^b ^c ^d ^e ^f ^g ^h "NASA's Kepler Mission Discovers Tiny Planet System". NASA. February 20, 2013. Retrieved February 21, 2013.

[space.com_kepler-37b-8] Smallest Alien Planet Kepler-37b Explained (Infographic)

[SWR-9] "Tiniest Planet Yet Discovered by NASA Outside our Solar System". scienceworldreport.com. February 21, 2013. Retrieved February 21, 2013.

[slate-10] "Astronomers Find the Tiniest Exoplanet Yet". Slate. February 20, 2013. Retrieved February 21, 2013.

[12] Centauri Dreams - Small Planets Confirm Kepler’s Capabilities

[latimes-13] "NASA, using Kepler space telescope, finds smallest planet yet". Los Angeles Times. February 20, 2013. Retrieved February 21, 2013.

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v t e The Kepler-37 system
Stars	Kepler-37
Planets	Kepler-37b Kepler-37c Kepler-37d Kepler-37e