Imaginary Picture of K2-137 b

Display orbital revolution of K2-137 b around the hoststar K2-137
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Exoplanet Name : K2-137 b
Alternate Name : "EPIC 228813918 b, 2MASS J12272899-0611428 b, WISE J122728.92-061142.7 b"
Radius (Rjup / Re): 0.0790 (Rjup) 0.8855 (Rearth)
Mass (Mjup / Me): 0.5000 (Mjup) 158.9690 (Mearth)
Semi Major Axis / Orbital Distance Calculated 0.0058 (AU) 0.0058 (AU Est.)
Eccentricity : 0.0000
Orbital Period(Yrs) 0.0005
Orbital Period(Observed/Estimated) 0.18 (Days Obs.) 0.24 (Days Est.)
Surface Gravity (G Earth) 202.7330
Star Radiation at Atmospheric Boundary: 1049424.3 (W/m2)
Measured Temperature (K) 0.0 (K)
Blackbody T 0.1(K) 1428.5 (K)
Blackbody T 0.3(K) 1341.5 (K)
Blackbody T 0.7(K) 1085.4 (K)
Tidally Locked Blackbody T 0.1(K) 1698.8 (K)
Tidally Locked Blackbody T 0.3(K) 1595.3 (K)
Size Class: Earth-size
Mass Class:
Detection Type : Primary Transit
Mass Detection : Radial Velocity
Radius Detection :
Habitability by Solar Eq. Astronomical Unit: Not habitable
Habitability by Kopparapu: Not habitable
Star Name : K2-137
Alternate Name : "2MASS J12272899-0611428, EPIC 228813918, EPIC 228813918, WISE J122728.92-061142.7"
Star Distance(LY) : 323.4
Stellar Radius(Rsun) : 0.4 (Rsun Measured)
Stellar Mass(Msun) : 0.5 (Msun Measured) 0.8 (Msun Estimated)
Star Age : 0.0 (GY)
Temperature : 3492 (K)
Spectral type : M3 V
UV portion[%]: 0.3
Visible portion[%]: 14.3
IR portion[%]: 85.4
Metalicity : 0.1
Absolute Magnitude: 10.5
Apparent Magnitude: 15.5
Right Ascension(RA) 186.8708
Declination (DEC) -6.1952
Hubble Space Telescope Guide Star Catalog (GSC) ID
Discovered by
Discovery Paper - Authors "A. M. S. Smith, J. Cabrera, Sz. Csizmadia, F. Dai, D. Gandolfi, T. Hirano, J. N. Winn, S. Albrecht, R. Alonso, G. Antoniciello, O. Barrag_n, H. Deeg, Ph. Eigm_ller, M. Endl, A. Erikson, M. Fridlund, A. Fukui, S. Grziwa, E. W. Guenther, A. P. Hatzes, D. Hidalgo, A. W. Howard, H. Isaacson, J. Korth, M. Kuzuhara, J. Livingston, N. Narita, D. Nespral, G. Nowak, E. Palle, M. P_tzold, C.M. Persson, E. Petigura, J. Prieto-Arranz, H. Rauer, I. Ribas, V. Van Eylen"
Discovery Paper - Title K2-137 b: an Earth-sized planet in a 4.3-hour orbit around an M-dwarf
Discovery Paper - Journal Earth and Planetary Astrophysics (astro-ph.EP)
Discovery Paper - URL https://arxiv.org/abs/1707.04549
SIMBAD LINK http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=K2-137+&submit=SIMBAD+search
Open Exoplanet Database Link
K2-137 b
K2-137 b

  • K2-137 b is an exoplanet orbiting the star K2-137, located about 323.4 light-years (99.2 pc) away from Solar System. Its discovery was publicly announced on 2017.
  • The host star K2-137 has apparent magnitude of 15.5, with absolute magnitude of 10.5.
  • It is 0.5 times more massive and 0.4 times bigger compared with our Sun. The surface temperature is 3492 with its spectral types of M3 V
  • In this planetary system, the extrasolar planet K2-137 b orbits around the star K2-137 every 0.2 days with its orbital distance of 0.01 AU ( 867667.7 km)
  • (Projected orbit of K2-137 b around its host star K2-137)


  • The Star K2-137 's habitable zone is located at the following distance
  • Inner Boundary (the orbital distance at Venus's Equivalent Radiation ) : 0.116 AU ( 17388385.5 km)
  • Earth Boundary (the orbital distance at Earth's Equivalent Radiation) : 0.161 AU ( 24035292.8 km)
  • Outer Boundary (the orbital distance at Mars's Equivalent Radiation) : 0.245 AU ( 36624467.3 km)
  • Snow Line (the orbital distance at Snow Line Equivalent Radiation) : 0.360 AU ( 53894508.0 km)
  • Radiation at Planetary Boundary of K2-137 b : 1049424.30 W/m2

    (Habitable zone calculated based on SEAU(Solar Equivalent Astronomical Unit) around the star K2-137)



  • Kopparapu Recent Venus for Star K2-137 distance : 0.131 AU
  • Kopparapu Runaway Greenhouse for Earth-sized planet for Star K2-137 distance : 0.166 AU
  • Kopparapu Runaway Greenhouse for Super-Earth-sized planet for Star K2-137 distance : 0.160 AU
  • Kopparapu Runaway Greenhouse for Mars-sized planet for Star K2-137 distance : 0.177 AU
  • Kopparapu Outer Boundary for Maximum Greenhouse for Star K2-137 distance : 0.324 AU
  • Kopparapu Outer Boundary for Early Mars for Star K2-137 distance : 0.341 AU

    (Habitable zone calculated based on Kopparapu et al.(2013) around the star K2-137)



  • Original Kopparapu Recent Venus for Star K2-137 distance : 0.130 AU
  • Original Kopparapu Runaway Greenhouse for Star K2-137 distance : 0.172 AU
  • Original Kopparapu Moist Greenhouse for Star K2-137 distance : 0.172 AU
  • Original Kopparapu Outer Boundary for Maximum Greenhouse for Star K2-137 distance : 0.329 AU
  • Original Kopparapu Outer Boundary for Early Mars for Star K2-137 distance : 0.342 AU

    (Habitable zone calculated based on Kopparapu et al.(Original) around the star K2-137)



    (Position in Stellar Map of star K2-137 and its Exoplanet K2-137 b)



    (Zoomed position in Stellar Map of star K2-137 and its Exoplanet K2-137 b (zoom level 3))

    (Synthetic Spectrum of star K2-137*)
    *Yamashiki YA et al. 2019 ApJ 881 114
    MUSCLES Paper I - France et al. 2016 ApJ 820 89
    MUSCLES Paper II- Youngblood et al. 2016 ApJ 824 101
    MUSCLES Paper III- Loyd et al. 2016 ApJ 824 102