Imaginary Picture of K2-258 b

Display orbital revolution of K2-258 b around the hoststar K2-258
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Exoplanet Name : K2-258 b
Alternate Name : "2MASS J12303152-0109391 b, EPIC 229017395 b, EPIC 229017395.01, WISE J123031.53-010939.3 b"
Status : Confirmed
Radius (Rjup / Re): 0.2680 (Rjup) 3.0040 (Rearth)
Mass (Mjup / Me): 0.0231 (Mjup) 7.3380 (Mearth)
Semi Major Axis / Orbital Distance Calculated 0.1490 (AU) 0.1490 (AU Est.)
Eccentricity : 0.0000
Orbital Period(Yrs) 0.0523
Orbital Period(Observed/Estimated) 19.09 (Days Obs.) 19.10 (Days Est.)
Surface Gravity (G Earth) 0.8132
Star Radiation at Atmospheric Boundary: 154220.9 (W/m2)
Measured Temperature (K) 0.0 (K)
Blackbody T 0.1(K) 884.5 (K)
Blackbody T 0.3(K) 830.6 (K)
Blackbody T 0.7(K) 672.0 (K)
Tidally Locked Blackbody T 0.1(K) 1051.8 (K)
Tidally Locked Blackbody T 0.3(K) 987.8 (K)
Size Class: sub-Neptune-size
Mass Class:
Detection Type : Primary Transit
Mass Detection :
Radius Detection :
Habitability by Solar Eq. Astronomical Unit: Not habitable
Habitability by Kopparapu: Not habitable
Star Name : K2-258
Alternate Name : "2MASS J12303152-0109391, EPIC 229017395, WISE J123031.53-010939.3"
Star Distance(LY) : 2090.9
Stellar Radius(Rsun) : 1.3 (Rsun Measured)
Stellar Mass(Msun) : 1.2 (Msun Measured) 1.2 (Msun Estimated)
Star Age : 0.0 (GY)
Temperature : 6351 (K)
Spectral type : F7
UV portion[%]: 0.3
Visible portion[%]: 1.5
IR portion[%]: 98.2
Metalicity : 0.0
Absolute Magnitude: 3.1
Apparent Magnitude: 12.1
Right Ascension(RA) 187.6313
Declination (DEC) -1.1609
Hubble Space Telescope Guide Star Catalog (GSC) ID
Discovered by
Discovery Paper - Authors
Discovery Paper - Title
Discovery Paper - Journal
Discovery Paper - URL
SIMBAD LINK https://simbad.u-strasbg.fr/simbad/sim-basic?Ident=K2-258&submit=SIMBAD+search
Open Exoplanet Database Link
K2-258 b
K2-258 b

  • K2-258 b is an exoplanet orbiting the star K2-258, located about 2090.9 light-years (641.1 pc) away from Solar System. Its discovery was publicly announced on 2018.
  • The host star K2-258 has apparent magnitude of 12.1, with absolute magnitude of 3.1.
  • It is 1.2 times more massive and 1.3 times bigger compared with our Sun. The surface temperature is 6351 with its spectral types of F7
  • In this planetary system, the extrasolar planet K2-258 b orbits around the star K2-258 every 19.1 days with its orbital distance of 0.15 AU ( 22290082.7 km)
  • (Projected orbit of K2-258 b around its host star K2-258)


  • The Star K2-258 's habitable zone is located at the following distance
  • Inner Boundary (the orbital distance at Venus's Equivalent Radiation ) : 1.145 AU ( 171243317.8 km)
  • Earth Boundary (the orbital distance at Earth's Equivalent Radiation) : 1.582 AU ( 236703016.4 km)
  • Outer Boundary (the orbital distance at Mars's Equivalent Radiation) : 2.411 AU ( 360683014.8 km)
  • Snow Line (the orbital distance at Snow Line Equivalent Radiation) : 3.548 AU ( 530760856.7 km)
  • Radiation at Planetary Boundary of K2-258 b : 154220.93 W/m2

    (Habitable zone calculated based on SEAU(Solar Equivalent Astronomical Unit) around the star K2-258)



  • Kopparapu Recent Venus for Star K2-258 distance : 1.146 AU
  • Kopparapu Runaway Greenhouse for Earth-sized planet for Star K2-258 distance : 1.451 AU
  • Kopparapu Runaway Greenhouse for Super-Earth-sized planet for Star K2-258 distance : 1.401 AU
  • Kopparapu Runaway Greenhouse for Mars-sized planet for Star K2-258 distance : 1.536 AU
  • Kopparapu Outer Boundary for Maximum Greenhouse for Star K2-258 distance : 2.531 AU
  • Kopparapu Outer Boundary for Early Mars for Star K2-258 distance : 2.669 AU

    (Habitable zone calculated based on Kopparapu et al.(2013) around the star K2-258)



  • Original Kopparapu Recent Venus for Star K2-258 distance : 1.162 AU
  • Original Kopparapu Runaway Greenhouse for Star K2-258 distance : 1.488 AU
  • Original Kopparapu Moist Greenhouse for Star K2-258 distance : 1.537 AU
  • Original Kopparapu Outer Boundary for Maximum Greenhouse for Star K2-258 distance : 2.576 AU
  • Original Kopparapu Outer Boundary for Early Mars for Star K2-258 distance : 2.679 AU

    (Habitable zone calculated based on Kopparapu et al.(Original) around the star K2-258)



    (Position in Stellar Map of star K2-258 and its Exoplanet K2-258 b)



    (Zoomed position in Stellar Map of star K2-258 and its Exoplanet K2-258 b (zoom level 3))

    (Synthetic Spectrum of star K2-258*)
    *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