Imaginary Picture of K2-4 b

Display orbital revolution of K2-4 b around the hoststar K2-4
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Exoplanet Name : K2-4 b
Alternate Name : "EPIC-201208431 b, 2MASS J11385895-0354202 b, EPIC 201208431 b, EPIC 201208431.01, WISE J113858.93-035420.0 b"
Status : Confirmed
Radius (Rjup / Re): 0.1870 (Rjup) 2.0961 (Rearth)
Mass (Mjup / Me): 0.0165 (Mjup) 5.2508 (Mearth)
Semi Major Axis / Orbital Distance Calculated 0.0780 (AU) 0.0780 (AU Est.)
Eccentricity : 0.0800
Orbital Period(Yrs) 0.0274
Orbital Period(Observed/Estimated) 10.00 (Days Obs.) 9.95 (Days Est.)
Surface Gravity (G Earth) 1.1951
Star Radiation at Atmospheric Boundary: 17001.0 (W/m2)
Measured Temperature (K) 0.0 (K)
Blackbody T 0.1(K) 509.6 (K)
Blackbody T 0.3(K) 478.6 (K)
Blackbody T 0.7(K) 387.2 (K)
Tidally Locked Blackbody T 0.1(K) 606.1 (K)
Tidally Locked Blackbody T 0.3(K) 569.2 (K)
Size Class: sub-Neptune-size
Mass Class:
Detection Type : Primary Transit
Mass Detection :
Radius Detection : Primary Transit
Habitability by Solar Eq. Astronomical Unit: Not habitable
Habitability by Kopparapu: Not habitable
Star Name : K2-4
Alternate Name : "EPIC 201208431, 2MASS J11385895-0354202, WISE J113858.93-035420.0"
Star Distance(LY) : 761.8
Stellar Radius(Rsun) : 0.6 (Rsun Measured)
Stellar Mass(Msun) : 0.6 (Msun Measured) 0.6 (Msun Estimated)
Star Age : 0.0 (GY)
Temperature : 4014 (K)
Spectral type : K7
UV portion[%]: 0.7
Visible portion[%]: 24.0
IR portion[%]: 75.3
Metalicity : -0.1
Absolute Magnitude: 5.5
Apparent Magnitude: 12.4
Right Ascension(RA) 174.7456
Declination (DEC) -3.9056
Hubble Space Telescope Guide Star Catalog (GSC) ID
Discovered by
Discovery Paper - Authors
Discovery Paper - Title
Discovery Paper - Journal 0
Discovery Paper - URL 0
SIMBAD LINK http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=K2-4+&submit=SIMBAD+search
Open Exoplanet Database Link
K2-4 b
K2-4 b

  • K2-4 b is an exoplanet orbiting the star K2-4, located about 761.8 light-years (233.6 pc) away from Solar System. Its discovery was publicly announced on 2015.
  • The host star K2-4 has apparent magnitude of 12.4, with absolute magnitude of 5.5.
  • It is 0.6 times more massive and 0.6 times bigger compared with our Sun. The surface temperature is 4014 with its spectral types of K7
  • In this planetary system, the extrasolar planet K2-4 b orbits around the star K2-4 every 10.0 days with its orbital distance of 0.08 AU ( 11668633.9 km)
  • (Projected orbit of K2-4 b around its host star K2-4)


  • The Star K2-4 's habitable zone is located at the following distance
  • Inner Boundary (the orbital distance at Venus's Equivalent Radiation ) : 0.199 AU ( 29763753.9 km)
  • Earth Boundary (the orbital distance at Earth's Equivalent Radiation) : 0.275 AU ( 41141286.0 km)
  • Outer Boundary (the orbital distance at Mars's Equivalent Radiation) : 0.419 AU ( 62690215.4 km)
  • Snow Line (the orbital distance at Snow Line Equivalent Radiation) : 0.617 AU ( 92251398.2 km)
  • Radiation at Planetary Boundary of K2-4 b : 17001.01 W/m2

    (Habitable zone calculated based on SEAU(Solar Equivalent Astronomical Unit) around the star K2-4)



  • Kopparapu Recent Venus for Star K2-4 distance : 0.223 AU
  • Kopparapu Runaway Greenhouse for Earth-sized planet for Star K2-4 distance : 0.282 AU
  • Kopparapu Runaway Greenhouse for Super-Earth-sized planet for Star K2-4 distance : 0.272 AU
  • Kopparapu Runaway Greenhouse for Mars-sized planet for Star K2-4 distance : 0.299 AU
  • Kopparapu Outer Boundary for Maximum Greenhouse for Star K2-4 distance : 0.535 AU
  • Kopparapu Outer Boundary for Early Mars for Star K2-4 distance : 0.564 AU

    (Habitable zone calculated based on Kopparapu et al.(2013) around the star K2-4)



  • Original Kopparapu Recent Venus for Star K2-4 distance : 0.220 AU
  • Original Kopparapu Runaway Greenhouse for Star K2-4 distance : 0.292 AU
  • Original Kopparapu Moist Greenhouse for Star K2-4 distance : 0.291 AU
  • Original Kopparapu Outer Boundary for Maximum Greenhouse for Star K2-4 distance : 0.543 AU
  • Original Kopparapu Outer Boundary for Early Mars for Star K2-4 distance : 0.565 AU

    (Habitable zone calculated based on Kopparapu et al.(Original) around the star K2-4)



    (Position in Stellar Map of star K2-4 and its Exoplanet K2-4 b)



    (Zoomed position in Stellar Map of star K2-4 and its Exoplanet K2-4 b (zoom level 3))

    (Synthetic Spectrum of star K2-4*)
    *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