K2-18b

K2-18b
Exoplanet List of exoplanets
Size comparison
Neptune K2-18b
Parent star
Star K2-18
Constellation Leo[1]
Right ascension (α) 11h 30m 14.5176s[2]
Declination (δ) 07° 35′ 18.257″[2]
Distance124.2±0.3[2] ly
(38.07±0.08[2] pc)
Spectral type M2.5 V[3]
Mass (m) 0.413±0.043[3] M☉
Radius (r) 0.394±0.038[3] R☉
Temperature (T) 3503±60[3] K
Metallicity [Fe/H] 0.090±0.090[3]
Age null[3] Gyr
Physical characteristics
Mass(m)7.96 (± 1.91) M⊕
Radius(r)2.24±0.23[3] R⊕
Temperature (T) 235 K (−38 °C; −37 °F)
Orbital elements
Semi-major axis(a) 0.1491[3] AU
Eccentricity (e) <0.43
Orbital period(P) 32.94488[3] d
Inclination (i) null[3]°
Discovery information
Discovery date 2015
Discoverer(s)
Discovery method Transit
Discovery site Kepler Space Observatory
Discovery status Confirmed

K2-18b also known as EPIC 201912552 b is an exoplanet orbiting the red dwarf star K2-18 every 33 days. It is 124 ly away[2] in the constellation Leo.[1]

Physical Characteristics

The planet may have a rocky surface and an atmosphere providing similar insulation to Earth's, according to a study published in mid-2017. However, the same study also states that the planet could be primarily water-based with a thick ice surface; as of yet, its exact structure is unknown. K2-18b is within the habitable zone of its star and could have oceans of liquid water on its surface.[4][5]

References

  1. 1 2 Roman, Nancy G. (1987). "Identification of a Constellation From a Position". Publications of the Astronomical Society of the Pacific. 99 (617): 695–699. Bibcode:1987PASP...99..695R. doi:10.1086/132034. Vizier query form
  2. 1 2 3 4 5 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 DR2 record for this source at VizieR.
  3. 1 2 3 4 5 6 7 8 9 10 "K2-18 b CONFIRMED PLANET OVERVIEW PAGE". NASA Exoplanet Archive. Retrieved 2015-10-17.
  4. ↑ "Two Super-Earths around star K2-18". 20 October 2017.
  5. ↑ Cloutier, R.; et al. (2017). "Characterization of the K2-18 multi-planetary system with HARPS. A habitable zone super-Earth and discovery of a second, warm super-Earth on a non-coplanar orbit". Astronomy and Astrophysics. 608 (35). A35. arXiv:1707.04292. Bibcode:2017A&A...608A..35C. doi:10.1051/0004-6361/201731558.


This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.