Imaginary Picture of K2-254 b

Display orbital revolution of K2-254 b around the hoststar K2-254
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Exoplanet Name : K2-254 b
Alternate Name : "2MASS J12221217-0443019 b, EPIC 228849382 b, EPIC 228849382.01, WISE J122212.18-044302.1 b"
Status : Confirmed
Radius (Rjup / Re): 0.1450 (Rjup) 1.6253 (Rearth)
Mass (Mjup / Me): 0.0130 (Mjup) 4.1446 (Mearth)
Semi Major Axis / Orbital Distance Calculated 0.0448 (AU) 0.0448 (AU Est.)
Eccentricity : 0.0000
Orbital Period(Yrs) 0.0112
Orbital Period(Observed/Estimated) 4.10 (Days Obs.) 4.11 (Days Est.)
Surface Gravity (G Earth) 1.5690
Star Radiation at Atmospheric Boundary: 125935.2 (W/m2)
Measured Temperature (K) 0.0 (K)
Blackbody T 0.1(K) 840.8 (K)
Blackbody T 0.3(K) 789.6 (K)
Blackbody T 0.7(K) 638.9 (K)
Tidally Locked Blackbody T 0.1(K) 999.9 (K)
Tidally Locked Blackbody T 0.3(K) 939.0 (K)
Size Class: super-Earth-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 : K2-254
Alternate Name : "2MASS J12221217-0443019, EPIC 228849382, WISE J122212.18-044302.1"
Star Distance(LY) : 748.2
Stellar Radius(Rsun) : 0.7 (Rsun Measured)
Stellar Mass(Msun) : 0.7 (Msun Measured) 0.7 (Msun Estimated)
Star Age : 0.0 (GY)
Temperature : 4629 (K)
Spectral type : K4
UV portion[%]: 2.0
Visible portion[%]: 33.1
IR portion[%]: 64.9
Metalicity : -0.1
Absolute Magnitude: 5.2
Apparent Magnitude: 12.0
Right Ascension(RA) 185.5508
Declination (DEC) -4.7172
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=K2-254&submit=SIMBAD+search
Open Exoplanet Database Link
K2-254 b
K2-254 b
  • K2-254 b is an exoplanet orbiting the star K2-254, located about 748.2 light-years (229.4 pc) away from Solar System. Its discovery was publicly announced on 2018.
  • The host star K2-254 has apparent magnitude of 12.0, with absolute magnitude of 5.2.
  • It is 0.7 times more massive and 0.7 times bigger compared with our Sun. The surface temperature is 4629 with its spectral types of K4
  • In this planetary system, the extrasolar planet K2-254 b orbits around the star K2-254 every 4.1 days with its orbital distance of 0.04 AU ( 6701984.6 km)
    • (Projected orbit of K2-254 b around its host star K2-254)


  • The Star K2-254 's habitable zone is located at the following distance
  • Inner Boundary (the orbital distance at Venus's Equivalent Radiation ) : 0.311 AU ( 46527238.5 km)
  • Earth Boundary (the orbital distance at Earth's Equivalent Radiation) : 0.430 AU ( 64312802.6 km)
  • Outer Boundary (the orbital distance at Mars's Equivalent Radiation) : 0.655 AU ( 97998478.8 km)
  • Snow Line (the orbital distance at Snow Line Equivalent Radiation) : 0.964 AU ( 144209054.6 km)
  • Radiation at Planetary Boundary of K2-254 b : 125935.19 W/m2

    (Habitable zone calculated based on SEAU(Solar Equivalent Astronomical Unit) around the star K2-254)



  • Kopparapu Recent Venus for Star K2-254 distance : 0.342 AU
  • Kopparapu Runaway Greenhouse for Earth-sized planet for Star K2-254 distance : 0.433 AU
  • Kopparapu Runaway Greenhouse for Super-Earth-sized planet for Star K2-254 distance : 0.418 AU
  • Kopparapu Runaway Greenhouse for Mars-sized planet for Star K2-254 distance : 0.459 AU
  • Kopparapu Outer Boundary for Maximum Greenhouse for Star K2-254 distance : 0.797 AU
  • Kopparapu Outer Boundary for Early Mars for Star K2-254 distance : 0.841 AU

    (Habitable zone calculated based on Kopparapu et al.(2013) around the star K2-254)



  • Original Kopparapu Recent Venus for Star K2-254 distance : 0.337 AU
  • Original Kopparapu Runaway Greenhouse for Star K2-254 distance : 0.447 AU
  • Original Kopparapu Moist Greenhouse for Star K2-254 distance : 0.447 AU
  • Original Kopparapu Outer Boundary for Maximum Greenhouse for Star K2-254 distance : 0.810 AU
  • Original Kopparapu Outer Boundary for Early Mars for Star K2-254 distance : 0.842 AU

    (Habitable zone calculated based on Kopparapu et al.(Original) around the star K2-254)



    (Position in Stellar Map of star K2-254 and its Exoplanet K2-254 b)



    (Zoomed position in Stellar Map of star K2-254 and its Exoplanet K2-254 b (zoom level 3))

    (Synthetic Spectrum of star K2-254*)
    *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