Imaginary Picture of K2-178 b

Display orbital revolution of K2-178 b around the hoststar K2-178
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Exoplanet Name : K2-178 b
Alternate Name : "2MASS J03313333+2226055 b, EPIC 210965800 b, EPIC 210965800.01, WISE J033133.32+222605.3 b"
Status : Confirmed
Radius (Rjup / Re): 0.3170 (Rjup) 3.5533 (Rearth)
Mass (Mjup / Me): 0.0270 (Mjup) 8.5782 (Mearth)
Semi Major Axis / Orbital Distance Calculated 0.0000 (AU) 0.0817 (AU Est.)
Eccentricity : 0.0000
Orbital Period(Yrs) 0.0239
Orbital Period(Observed/Estimated) 8.75 (Days Obs.) 0.00 (Days Est.)
Surface Gravity (G Earth) 0.6794
Star Radiation at Atmospheric Boundary: 135670.5 (W/m2)
Measured Temperature (K) 0.0 (K)
Blackbody T 0.1(K) 856.6 (K)
Blackbody T 0.3(K) 804.4 (K)
Blackbody T 0.7(K) 650.9 (K)
Tidally Locked Blackbody T 0.1(K) 1018.6 (K)
Tidally Locked Blackbody T 0.3(K) 956.6 (K)
Size Class: 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 : K2-178
Alternate Name : "2MASS J03313333+2226055, EPIC 210965800, WISE J033133.32+222605.3"
Star Distance(LY) : 706.6
Stellar Radius(Rsun) : 0.9 (Rsun Measured)
Stellar Mass(Msun) : 0.9 (Msun Measured) 1.0 (Msun Estimated)
Star Age : 0.0 (GY)
Temperature : 5525 (K)
Spectral type : G7
UV portion[%]: 7.0
Visible portion[%]: 43.4
IR portion[%]: 49.6
Metalicity : 0.1
Absolute Magnitude: 4.1
Apparent Magnitude: 10.8
Right Ascension(RA) 52.8889
Declination (DEC) 22.4349
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=K2-178+&submit=SIMBAD+search
Open Exoplanet Database Link
K2-178 b
K2-178 b

  • K2-178 b is an exoplanet orbiting the star K2-178, located about 706.6 light-years (216.7 pc) away from Solar System. Its discovery was publicly announced on 2018.
  • The host star K2-178 has apparent magnitude of 10.8, 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 5525 with its spectral types of G7
  • In this planetary system, the extrasolar planet K2-178 b orbits around the star K2-178 every 8.7 days with its orbital distance of 0.08 AU ( 12219111.4 km)
  • (Projected orbit of K2-178 b around its host star K2-178)


  • The Star K2-178 's habitable zone is located at the following distance
  • Inner Boundary (the orbital distance at Venus's Equivalent Radiation ) : 0.589 AU ( 88046619.0 km)
  • Earth Boundary (the orbital distance at Earth's Equivalent Radiation) : 0.814 AU ( 121703436.8 km)
  • Outer Boundary (the orbital distance at Mars's Equivalent Radiation) : 1.240 AU ( 185449104.8 km)
  • Snow Line (the orbital distance at Snow Line Equivalent Radiation) : 1.824 AU ( 272896481.7 km)
  • Radiation at Planetary Boundary of K2-178 b : 135670.53 W/m2

    (Habitable zone calculated based on SEAU(Solar Equivalent Astronomical Unit) around the star K2-178)



  • Kopparapu Recent Venus for Star K2-178 distance : 0.619 AU
  • Kopparapu Runaway Greenhouse for Earth-sized planet for Star K2-178 distance : 0.784 AU
  • Kopparapu Runaway Greenhouse for Super-Earth-sized planet for Star K2-178 distance : 0.757 AU
  • Kopparapu Runaway Greenhouse for Mars-sized planet for Star K2-178 distance : 0.830 AU
  • Kopparapu Outer Boundary for Maximum Greenhouse for Star K2-178 distance : 1.395 AU
  • Kopparapu Outer Boundary for Early Mars for Star K2-178 distance : 1.471 AU

    (Habitable zone calculated based on Kopparapu et al.(2013) around the star K2-178)



  • Original Kopparapu Recent Venus for Star K2-178 distance : 0.617 AU
  • Original Kopparapu Runaway Greenhouse for Star K2-178 distance : 0.806 AU
  • Original Kopparapu Moist Greenhouse for Star K2-178 distance : 0.816 AU
  • Original Kopparapu Outer Boundary for Maximum Greenhouse for Star K2-178 distance : 1.419 AU
  • Original Kopparapu Outer Boundary for Early Mars for Star K2-178 distance : 1.476 AU

    (Habitable zone calculated based on Kopparapu et al.(Original) around the star K2-178)



    (Position in Stellar Map of star K2-178 and its Exoplanet K2-178 b)



    (Zoomed position in Stellar Map of star K2-178 and its Exoplanet K2-178 b (zoom level 3))

    (Synthetic Spectrum of star K2-178*)
    *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