Imaginary Picture of K2-208 b

Display orbital revolution of K2-208 b around the hoststar K2-208
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Exoplanet Name : K2-208 b
Alternate Name : "2MASS J01230698+0053210 b, EPIC 220225178 b, EPIC 220225178.01, WISE J012306.96+005320.5 b"
Status : Confirmed
Radius (Rjup / Re): 0.1500 (Rjup) 1.6813 (Rearth)
Mass (Mjup / Me): 0.0135 (Mjup) 4.2774 (Mearth)
Semi Major Axis / Orbital Distance Calculated 0.0000 (AU) 0.0497 (AU Est.)
Eccentricity : 0.0000
Orbital Period(Yrs) 0.0115
Orbital Period(Observed/Estimated) 4.19 (Days Obs.) 0.00 (Days Est.)
Surface Gravity (G Earth) 1.5131
Star Radiation at Atmospheric Boundary: 357116.3 (W/m2)
Measured Temperature (K) 0.0 (K)
Blackbody T 0.1(K) 1091.1 (K)
Blackbody T 0.3(K) 1024.6 (K)
Blackbody T 0.7(K) 829.0 (K)
Tidally Locked Blackbody T 0.1(K) 1297.5 (K)
Tidally Locked Blackbody T 0.3(K) 1218.5 (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 : K2-208
Alternate Name : "2MASS J01230698+0053210, EPIC 220225178, WISE J012306.96+005320.5"
Star Distance(LY) : 850.3
Stellar Radius(Rsun) : 0.9 (Rsun Measured)
Stellar Mass(Msun) : 0.9 (Msun Measured) 0.9 (Msun Estimated)
Star Age : 0.0 (GY)
Temperature : 5582 (K)
Spectral type : G6
UV portion[%]: 7.2
Visible portion[%]: 43.8
IR portion[%]: 49.0
Metalicity : -0.1
Absolute Magnitude: 4.1
Apparent Magnitude: 11.2
Right Ascension(RA) 20.7791
Declination (DEC) 0.8892
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=K2-208&submit=SIMBAD+search
Open Exoplanet Database Link
K2-208 b
K2-208 b

  • K2-208 b is an exoplanet orbiting the star K2-208, located about 850.3 light-years (260.7 pc) away from Solar System. Its discovery was publicly announced on 2018.
  • The host star K2-208 has apparent magnitude of 11.2, with absolute magnitude of 4.1.
  • It is 0.9 times more massive and 0.9 times bigger compared with our Sun. The surface temperature is 5582 with its spectral types of G6
  • In this planetary system, the extrasolar planet K2-208 b orbits around the star K2-208 every 4.2 days with its orbital distance of 0.05 AU ( 7428499.4 km)
  • (Projected orbit of K2-208 b around its host star K2-208)


  • The Star K2-208 's habitable zone is located at the following distance
  • Inner Boundary (the orbital distance at Venus's Equivalent Radiation ) : 0.581 AU ( 86843282.0 km)
  • Earth Boundary (the orbital distance at Earth's Equivalent Radiation) : 0.802 AU ( 120040110.6 km)
  • Outer Boundary (the orbital distance at Mars's Equivalent Radiation) : 1.223 AU ( 182914563.7 km)
  • Snow Line (the orbital distance at Snow Line Equivalent Radiation) : 1.799 AU ( 269166793.5 km)
  • Radiation at Planetary Boundary of K2-208 b : 357116.30 W/m2

    (Habitable zone calculated based on SEAU(Solar Equivalent Astronomical Unit) around the star K2-208)



  • Kopparapu Recent Venus for Star K2-208 distance : 0.609 AU
  • Kopparapu Runaway Greenhouse for Earth-sized planet for Star K2-208 distance : 0.771 AU
  • Kopparapu Runaway Greenhouse for Super-Earth-sized planet for Star K2-208 distance : 0.744 AU
  • Kopparapu Runaway Greenhouse for Mars-sized planet for Star K2-208 distance : 0.816 AU
  • Kopparapu Outer Boundary for Maximum Greenhouse for Star K2-208 distance : 1.369 AU
  • Kopparapu Outer Boundary for Early Mars for Star K2-208 distance : 1.444 AU

    (Habitable zone calculated based on Kopparapu et al.(2013) around the star K2-208)



  • Original Kopparapu Recent Venus for Star K2-208 distance : 0.607 AU
  • Original Kopparapu Runaway Greenhouse for Star K2-208 distance : 0.793 AU
  • Original Kopparapu Moist Greenhouse for Star K2-208 distance : 0.803 AU
  • Original Kopparapu Outer Boundary for Maximum Greenhouse for Star K2-208 distance : 1.393 AU
  • Original Kopparapu Outer Boundary for Early Mars for Star K2-208 distance : 1.448 AU

    (Habitable zone calculated based on Kopparapu et al.(Original) around the star K2-208)



    (Position in Stellar Map of star K2-208 and its Exoplanet K2-208 b)



    (Zoomed position in Stellar Map of star K2-208 and its Exoplanet K2-208 b (zoom level 3))

    (Synthetic Spectrum of star K2-208*)
    *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