NASA Artist Impression of Kepler-37b
|Discovery date||February 20, 2013|
Kepler-37b is an extrasolar planet (exoplanet) orbiting Kepler-37 in the constellation Lyra. 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. The measurements do not constrain its mass, but masses above a few times that of the Moon give unphysically high densities.
Kepler-37b, along with two other planets, Kepler-37c and Kepler-37d, were discovered by the Kepler space telescope, which observes stellar transits. 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] Kepler-37 is currently the smallest star to be studied using this process. This allowed the size of Kepler-37b to be determined "with extreme accuracy".
To date, Kepler-37b is the smallest planet discovered around a main-sequence star[b] outside the Solar System. 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. 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".
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. The outer two planets in the system have orbital periods within one percent of the 8:5 and 3:1 resonances with Kepler-37b's period.
Kepler-37b is located approximately 210 light-years from Earth. It is slightly larger than the Moon, with a diameter of about 3,900 kilometres (2,400 mi). NASA states that it probably has no atmosphere and cannot support life. Furthermore, it is most likely composed of rocky materials. 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).
- 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 (journal) 494 (7438): 452–4. arXiv:1305.5587. Bibcode:2013Natur.494..452B. doi:10.1038/nature11914. ISSN 0028-0836. PMID 23426260. Retrieved 2013-02-21.
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- Smallest Alien Planet Kepler-37b Explained (Infographic)
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- Centauri Dreams - Small Planets Confirm Kepler’s Capabilities
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PSR B1257+12 A
|Least massive exoplanet