Kepler-37

From Wikipedia, the free encyclopedia
Jump to navigation Jump to search

Kepler-37
A Moon-size Line Up.jpg
Line up comparing the Kepler-37 planets system to the moon and planets in the Solar System.
Observation data
Epoch J2000      Equinox J2000
Constellation Lyra
Right ascension  18h 56m 14.3078s[1]
Declination 44° 31′ 05.389″[1]
Apparent magnitude (V) 9.710[2]
Characteristics
Spectral type G8V
Astrometry
Proper motion (μ) RA: −60.520±0.053[1] mas/yr
Dec.: 48.694±0.050[1] mas/yr
Parallax (π)15.6155 ± 0.0290[1] mas
Distance208.9 ± 0.4 ly
(64.0 ± 0.1 pc)
Details
Mass0.803 (± 0.07)[3] M
Radius0.77 (± 0.026)[3] R
Temperature5417 (± 75)[3] K
Metallicity [Fe/H]–0.32 (± 0.07)[3] dex
Rotational velocity (v sin i)1.1 (± 1.1)[3] km/s
Age5.66 Gyr
Other designations
KOI-245, KIC 8478994,[2] TYC 3131-1199-1[4]
Database references
SIMBADdata
Extrasolar Planets
Encyclopaedia
data
KICdata

Kepler-37, also known as UGA-1785,[5][6][7] is a G-type main-sequence star located in the constellation Lyra 209 light years from Earth. It is host to exoplanets Kepler-37b, Kepler-37c, Kepler-37d and Kepler-37e, all of which orbit very close to it. Kepler-37 has a mass about 80.3 percent of the Sun's and a radius about 77 percent as large.[8] It has a temperature similar to that of the Sun, but a bit cooler at 5,417 K. It has about half the metallicity of our Sun. With an age of roughly 6 billion years,[9] it is slightly older than the Sun, but is still a main-sequence star. Until January 2015, Kepler-37 was the smallest star to be measured via asteroseismology.[10]

Planetary system[edit]

The Kepler-37 planetary system[8]
Companion
(in order from star)
Mass Semimajor axis
(AU)
Orbital period
(days)
Eccentricity Inclination Radius
b 0.01[a] M 0.1003 13.367308 88.63° 0.354 R
c 0.1368 21.301886 89.07° 0.742 R
d 0.2076 39.792187 89.335° 1.99 R
e 0.2508 51.196

Kepler-37b is the closest planet to the Kepler-37. At the time of its discovery in February 2013, it was the smallest known exoplanet.[11] At 3,865 kilometres (2,402 mi) in diameter, it is slightly larger than the Moon.[11] It orbits Kepler-37 once every 13 days at a distance of about 0.1 astronomical units (AU).[8] Kepler-37b has a rocky surface and is believed to be too small and too close to its star to support water or maintain an atmosphere.[11] Surface temperature is estimated at 700 K (427 °C; 800 °F).[10]

Kepler-37c is around three-quarters of the diameter of Earth and orbits approximately every 21 days at a distance of just under 0.14 AU. Kepler-37d is about twice the diameter of Earth. It orbits in around 40 days at a distance of nearly 0.21 AU.[8] Neither is able to support water due to their proximity to Kepler-37.[11]

The periods of the three inner planets are close (within one per cent) to a 5:8:15 mean-motion resonance relationship.

Discovery[edit]

The Kepler planets were discovered in September 2012 with the aid of transit events detected by the Kepler space telescope, and announced to the public in February 2013.[8] Computer simulation was used to rule out other astronomical phenomenon mimicking planetary transit with probabilities of error <0.05% (3σ) for each potential planet. Additionally, simulation demonstrated that the proposed planetary configuration was stable.[8] The exoplanets were considerably smaller than any previously detected, leading Science World Reports to state that "a major technological improvement for the telescope" had been achieved.[11]

Thomas Barclay, an astrophysicist on the Kepler space telescope team, said the discovery was "really good news" in the search for hospitable planets, a prime objective of the project, because it demonstrated the telescope was capable of detecting Earth-sized planets.[12] However, he does not anticipate finding many planets as small as Kepler-37b due to the very small amount of light such planets obscure.[12] According to NASA scientist Jack Lissauer, the discovery of Kepler-37b "suggests such little planets are common, and more planetary wonders await as we continue to gather and analyze additional data."[10] Astronomer John Johnson of Caltech university said the discovery would have been "unimaginable" a few years ago and that the telescope had revolutionized astronomers' picture of the universe.[12]

The asteroseismology work was, in part, paid for by White Dwarf Research Corporation, a crowd funded non-profit organization.[13]

In 2014, a fourth planet with orbital period of 51 days was confirmed through transit timing variations. Previously this signal was thought to be a false positive.[14]

Notes[edit]

  1. ^ Masses more than a few times that of the Moon result in unphysically high densities.

References[edit]

  1. ^ a b c d e Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia Data Release 2 Vizier catalog entry
  2. ^ a b "Kepler Host Star Characteristics". Archive for Space Telescopes. STSI. 2012-02-24. Retrieved 2013-02-21.
  3. ^ a b c d e Barclay, T; Rowe, JF; Lissauer, JJ; et al. (2013-02-20). "A sub-Mercury-sized exoplanet (Additional Information)" (PDF). Nature. 494 (7438): 452–4. arXiv:1305.5587. Bibcode:2013Natur.494..452B. doi:10.1038/nature11914. PMID 23426260. Retrieved 2013-02-21.
  4. ^ "TYC 3131-1199-1". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2013-02-22.
  5. ^ Planets in Kepler-37 star system designated ‘UGA-1785’ by NASA
  6. ^ 211 light years away, star system named for UGA
  7. ^ Kepler-37, Open Exoplanet catalogue
  8. ^ a b c d e 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.; Lopez, Eric D.; Marcy, Geoffrey W.; Mullally, Fergal; Ragozzine, Darin; Torres, Guillermo; Adams, Elisabeth R.; Agol, Eric; Barrado, David; Basu, Sarbani; Bedding, Timothy R.; Buchhave, Lars A.; Charbonneau, David; Christiansen, Jessie L.; Christensen-Dalsgaard, Jørgen; Ciardi, David; Cochran, William D.; Dupree, Andrea K.; Elsworth, Yvonne; Everett, Mark; Fischer, Debra A.; et al. (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.
  9. ^ Smallest Alien Planet Kepler-37b Explained (Infographic)
  10. ^ a b c "NASA's Kepler Mission Discovers Tiny Planet System" (Press release). NASA. February 20, 2012. Retrieved February 21, 2012.
  11. ^ a b c d e Catherine Griffin (February 21, 2013). "Tiniest Planet Yet Discovered by NASA Outside our Solar System". Science World Report. Retrieved February 21, 2013.
  12. ^ a b c Eryn Brown (February 21, 2013). "NASA, using Kepler space telescope, finds smallest planet yet". LA Times. Retrieved February 21, 2013.
  13. ^ Phil Plait (February 20, 2013). "Astronomers Find the Tiniest Exoplanet Yet". Bad Astronomy blog. Slate. Retrieved February 21, 2013.
  14. ^ Hadden, Sam; Lithwick, Yoram (2014). "Densities and Eccentricities of 139 Kepler Planets from Transit Time Variations". The Astrophysical Journal. 787: 80. arXiv:1310.7942. Bibcode:2014ApJ...787...80H. doi:10.1088/0004-637X/787/1/80.

Further reading[edit]

External links[edit]

Coordinates: Sky map 18h 56m 14.32s, +44° 31′ 05.3″