K2-187, also known as EPIC 212157262, is a Sun-like star in K2 Campaign 5. It is very close in size and temperature to the Sun, and has a system of four confirmed exoplanets ranging between 1.4 R🜨 and 3.2 R🜨. The innermost planet takes just 18 hours to orbit its star, while the outermost planet orbits every 2 weeks.[2]

K2-187[1]
Observation data
Epoch J2000      Equinox J2000
Constellation Cancer
Right ascension 08h 50m 05.67s
Declination +23° 11′ 33.36″
Apparent magnitude (V) 12.864 (Kepler magnitude)[2]
Characteristics
Spectral type G
Astrometry
Proper motion (μ) RA: -11.864 mas/yr
Dec.: -30.702 mas/yr
Parallax (π)2.9939 ± 0.0510 mas[3]
Distance1,090 ± 20 ly
(334 ± 6 pc)
Details
Mass0.966999 +0.025227
−0.024169
[1] M
Radius0.894913 +0.041087
−0.025505
[1] R
Temperature5477 ± 50[2] K
Metallicity [Fe/H]+0.26 ± 0.08[2] dex
Other designations
EPIC 212157262, K2-187, WISE J085005.65+231133.0, 2MASS J08500566+2311333
Database references
SIMBADdata

Planetary system

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K2-187 has at least four orbiting exoplanets: two Super-Earths, one Hot Neptune, and one Mini-Neptune. All four planets are in near-resonances with each other and are far too hot for life.

 
Size comparison of the known planets of K2-187 (artistic concept) with Earth
The K2-187 planetary system[2][1] [4]
Companion
(in order from star)
Mass Semimajor axis
(AU)
Orbital period
(days)
Eccentricity Inclination Radius
b 0.016322 0.773981+0.000052
−0.000050
81.930168+5.825258
−11.735217
°
1.30+0.13
−0.13
 R🜨
c 0.0391185 2.871788+0.000256
−0.000257
86.067367+2.836604
−6.998926
°
1.80+0.14
−0.14
 R🜨
d 0.0718533 7.149079+0.000360
−0.000372
87.483206+1.886985
−3.903548
°
3.17+0.18
−0.18
 R🜨
e 0.11036 13.608341+0.001661
−0.001580
88.970197+0.751147
−1.318388
°
2.38+0.18
−0.18
 R🜨


References

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  1. ^ a b c d "K2-187 PLANET HOST OVERVIEW PAGE". NASA Exoplanet Archive. Retrieved 2018-03-05.
  2. ^ a b c d e "Andrew W. Mayo" (PDF).
  3. ^ 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.
  4. ^ Livingston, John H.; Crossfield, Ian J. M.; Petigura, Erik A.; Gonzales, Erica J.; Ciardi, David R.; Beichman, Charles A.; Christiansen, Jessie L.; Dressing, Courtney D.; Henning, Thomas; Howard, Andrew W.; Isaacson, Howard; Fulton, Benjamin J.; Kosiarek, Molly; Schlieder, Joshua E.; Sinukoff, Evan; Tamura, Motohide (2018). "Sixty Validated Planets from K2 Campaigns 5–8". The Astronomical Journal. 156 (6): 277. arXiv:1810.04074. Bibcode:2018AJ....156..277L. doi:10.3847/1538-3881/aae778. S2CID 119387939.