Imaginary Picture of K2-125 b

Display orbital revolution of K2-125 b around the hoststar K2-125
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Exoplanet Name : K2-125 b
Alternate Name : "EPIC 212398486 b, 2MASS J13363410-1456512 b, EPIC 212398486.01, WISE J133634.07-145651.8 b"
Status : Confirmed
Radius (Rjup / Re): 0.1940 (Rjup) 2.1745 (Rearth)
Mass (Mjup / Me): 0.0171 (Mjup) 5.4333 (Mearth)
Semi Major Axis / Orbital Distance Calculated 0.1210 (AU) 0.1210 (AU Est.)
Eccentricity : 0.0800
Orbital Period(Yrs) 0.0595
Orbital Period(Observed/Estimated) 21.75 (Days Obs.) 21.96 (Days Est.)
Surface Gravity (G Earth) 1.1490
Star Radiation at Atmospheric Boundary: 2389.1 (W/m2)
Measured Temperature (K) 0.0 (K)
Blackbody T 0.1(K) 312.0 (K)
Blackbody T 0.3(K) 293.0 (K)
Blackbody T 0.7(K) 237.1 (K)
Tidally Locked Blackbody T 0.1(K) 371.1 (K)
Tidally Locked Blackbody T 0.3(K) 348.5 (K)
Size Class: sub-Neptune-size
Mass Class:
Detection Type : Primary Transit
Mass Detection :
Radius Detection : Primary Transit
Habitability by Solar Eq. Astronomical Unit: Habitable
Habitability by Kopparapu: Not habitable
Star Name : K2-125
Alternate Name : "EPIC 212398486, 2MASS J13363410-1456512, WISE J133634.07-145651.8"
Star Distance(LY) : 414.9
Stellar Radius(Rsun) : 0.4 (Rsun Measured)
Stellar Mass(Msun) : 0.5 (Msun Measured) 0.5 (Msun Estimated)
Star Age : 0.0 (GY)
Temperature : 3654 (K)
Spectral type : M2V
UV portion[%]: 0.4
Visible portion[%]: 17.5
IR portion[%]: 82.1
Metalicity : 0.0
Absolute Magnitude: 7.1
Apparent Magnitude: 12.6
Right Ascension(RA) 204.1421
Declination (DEC) -14.9476
Hubble Space Telescope Guide Star Catalog (GSC) ID
Discovered by
Discovery Paper - Authors
Discovery Paper - Title
Discovery Paper - Journal
Discovery Paper - URL
SIMBAD LINK http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=K2-125+&submit=SIMBAD+search
Open Exoplanet Database Link
K2-125 b
K2-125 b

  • K2-125 b is an exoplanet orbiting the star K2-125, located about 414.9 light-years (127.2 pc) away from Solar System. Its discovery was publicly announced on 2017.
  • The host star K2-125 has apparent magnitude of 12.6, with absolute magnitude of 7.1.
  • It is 0.5 times more massive and 0.4 times bigger compared with our Sun. The surface temperature is 3654 with its spectral types of M2V
  • In this planetary system, the extrasolar planet K2-125 b orbits around the star K2-125 every 21.8 days with its orbital distance of 0.12 AU ( 18101342.4 km)
  • (Projected orbit of K2-125 b around its host star K2-125)


  • The Star K2-125 's habitable zone is located at the following distance
  • Inner Boundary (the orbital distance at Venus's Equivalent Radiation ) : 0.116 AU ( 17308330.9 km)
  • Earth Boundary (the orbital distance at Earth's Equivalent Radiation) : 0.160 AU ( 23924636.5 km)
  • Outer Boundary (the orbital distance at Mars's Equivalent Radiation) : 0.244 AU ( 36455851.6 km)
  • Snow Line (the orbital distance at Snow Line Equivalent Radiation) : 0.359 AU ( 53646382.6 km)
  • Radiation at Planetary Boundary of K2-125 b : 2389.07 W/m2

    (Habitable zone calculated based on SEAU(Solar Equivalent Astronomical Unit) around the star K2-125)



  • Kopparapu Recent Venus for Star K2-125 distance : 0.130 AU
  • Kopparapu Runaway Greenhouse for Earth-sized planet for Star K2-125 distance : 0.165 AU
  • Kopparapu Runaway Greenhouse for Super-Earth-sized planet for Star K2-125 distance : 0.159 AU
  • Kopparapu Runaway Greenhouse for Mars-sized planet for Star K2-125 distance : 0.175 AU
  • Kopparapu Outer Boundary for Maximum Greenhouse for Star K2-125 distance : 0.319 AU
  • Kopparapu Outer Boundary for Early Mars for Star K2-125 distance : 0.336 AU

    (Habitable zone calculated based on Kopparapu et al.(2013) around the star K2-125)



  • Original Kopparapu Recent Venus for Star K2-125 distance : 0.129 AU
  • Original Kopparapu Runaway Greenhouse for Star K2-125 distance : 0.171 AU
  • Original Kopparapu Moist Greenhouse for Star K2-125 distance : 0.171 AU
  • Original Kopparapu Outer Boundary for Maximum Greenhouse for Star K2-125 distance : 0.324 AU
  • Original Kopparapu Outer Boundary for Early Mars for Star K2-125 distance : 0.337 AU

    (Habitable zone calculated based on Kopparapu et al.(Original) around the star K2-125)



    (Position in Stellar Map of star K2-125 and its Exoplanet K2-125 b)



    (Zoomed position in Stellar Map of star K2-125 and its Exoplanet K2-125 b (zoom level 3))

    (Synthetic Spectrum of star K2-125*)
    *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