Imaginary Picture of K2-308 b

Display orbital revolution of K2-308 b around the hoststar K2-308
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Exoplanet Name : K2-308 b
Alternate Name : "EPIC 246865365 b, 2MASS J05132138+1624510 b, WISE J051321.40+162451.1 b"
Status : Confirmed
Radius (Rjup / Re): 0.8840 (Rjup) 9.9088 (Rearth)
Mass (Mjup / Me): 0.0250 (Mjup) 7.9485 (Mearth)
Semi Major Axis / Orbital Distance Calculated 0.0000 (AU) 0.0454 (AU Est.)
Eccentricity : 0.0000
Orbital Period(Yrs) 0.0093
Orbital Period(Observed/Estimated) 3.39 (Days Obs.) 0.00 (Days Est.)
Surface Gravity (G Earth) 0.0810
Star Radiation at Atmospheric Boundary: 1265628.8 (W/m2)
Measured Temperature (K) 0.0 (K)
Blackbody T 0.1(K) 1497.0 (K)
Blackbody T 0.3(K) 1405.8 (K)
Blackbody T 0.7(K) 1137.5 (K)
Tidally Locked Blackbody T 0.1(K) 1780.2 (K)
Tidally Locked Blackbody T 0.3(K) 1671.8 (K)
Size Class: Jupiter-size
Mass Class:
Detection Type : Primary Transit
Mass Detection : Radial Velocity
Radius Detection : Primary Transit
Habitability by Solar Eq. Astronomical Unit: Not habitable
Habitability by Kopparapu: Not habitable
Star Name : K2-308
Alternate Name : "EPIC 246865365, 2MASS J05132138+1624510, WISE J051321.40+162451.1"
Star Distance(LY) : 4941.8
Stellar Radius(Rsun) : 1.2 (Rsun Measured)
Stellar Mass(Msun) : 1.1 (Msun Measured) 1.1 (Msun Estimated)
Star Age : 0.0 (GY)
Temperature : 6100 (K)
Spectral type : G0
UV portion[%]: 7.8
Visible portion[%]: 44.8
IR portion[%]: 47.4
Metalicity : -0.1
Absolute Magnitude: 4.1
Apparent Magnitude: 15.0
Right Ascension(RA) 78.3391
Declination (DEC) 16.4142
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=K2-308+&submit=SIMBAD+search
Open Exoplanet Database Link
K2-308 b
K2-308 b

  • K2-308 b is an exoplanet orbiting the star K2-308, located about 4941.8 light-years (1515.2 pc) away from Solar System. Its discovery was publicly announced on 2019.
  • The host star K2-308 has apparent magnitude of 15.0, with absolute magnitude of 4.1.
  • It is 1.1 times more massive and 1.2 times bigger compared with our Sun. The surface temperature is 6100 with its spectral types of G0
  • In this planetary system, the extrasolar planet K2-308 b orbits around the star K2-308 every 3.4 days with its orbital distance of 0.05 AU ( 6794476.6 km)
  • (Projected orbit of K2-308 b around its host star K2-308)


  • The Star K2-308 's habitable zone is located at the following distance
  • Inner Boundary (the orbital distance at Venus's Equivalent Radiation ) : 1.000 AU ( 149533833.7 km)
  • Earth Boundary (the orbital distance at Earth's Equivalent Radiation) : 1.382 AU ( 206694836.0 km)
  • Outer Boundary (the orbital distance at Mars's Equivalent Radiation) : 2.105 AU ( 314957188.6 km)
  • Snow Line (the orbital distance at Snow Line Equivalent Radiation) : 3.098 AU ( 463473300.4 km)
  • Radiation at Planetary Boundary of K2-308 b : 1265628.76 W/m2

    (Habitable zone calculated based on SEAU(Solar Equivalent Astronomical Unit) around the star K2-308)



  • Kopparapu Recent Venus for Star K2-308 distance : 1.016 AU
  • Kopparapu Runaway Greenhouse for Earth-sized planet for Star K2-308 distance : 1.287 AU
  • Kopparapu Runaway Greenhouse for Super-Earth-sized planet for Star K2-308 distance : 1.243 AU
  • Kopparapu Runaway Greenhouse for Mars-sized planet for Star K2-308 distance : 1.362 AU
  • Kopparapu Outer Boundary for Maximum Greenhouse for Star K2-308 distance : 2.254 AU
  • Kopparapu Outer Boundary for Early Mars for Star K2-308 distance : 2.378 AU

    (Habitable zone calculated based on Kopparapu et al.(2013) around the star K2-308)



  • Original Kopparapu Recent Venus for Star K2-308 distance : 1.024 AU
  • Original Kopparapu Runaway Greenhouse for Star K2-308 distance : 1.321 AU
  • Original Kopparapu Moist Greenhouse for Star K2-308 distance : 1.355 AU
  • Original Kopparapu Outer Boundary for Maximum Greenhouse for Star K2-308 distance : 2.295 AU
  • Original Kopparapu Outer Boundary for Early Mars for Star K2-308 distance : 2.386 AU

    (Habitable zone calculated based on Kopparapu et al.(Original) around the star K2-308)



    (Position in Stellar Map of star K2-308 and its Exoplanet K2-308 b)



    (Zoomed position in Stellar Map of star K2-308 and its Exoplanet K2-308 b (zoom level 3))

    (Synthetic Spectrum of star K2-308*)
    *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