Imaginary Picture of K2-398 c

Display orbital revolution of K2-398 c around the hoststar K2-398
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Exoplanet Name : K2-398 c
Alternate Name :
Status : Confirmed
Radius (Rjup / Re): 0.4548 (Rjup) 5.0981 (Rearth)
Mass (Mjup / Me): 0.0737 (Mjup) 23.4193 (Mearth)
Semi Major Axis / Orbital Distance Calculated 0.1362 (AU) 0.1362 (AU Est.)
Eccentricity : 0.0000
Orbital Period(Yrs) 0.0514
Orbital Period(Observed/Estimated) 18.79 (Days Obs.) 18.89 (Days Est.)
Surface Gravity (G Earth) 0.9011
Star Radiation at Atmospheric Boundary: 126850.7 (W/m2)
Measured Temperature (K) 0.0 (K)
Blackbody T 0.1(K) 842.3 (K)
Blackbody T 0.3(K) 791.0 (K)
Blackbody T 0.7(K) 640.0 (K)
Tidally Locked Blackbody T 0.1(K) 1001.7 (K)
Tidally Locked Blackbody T 0.3(K) 940.7 (K)
Size Class: Neptune-size
Mass Class:
Detection Type : Primary Transit
Mass Detection : Theoretical
Radius Detection : Primary Transit
Habitability by Solar Eq. Astronomical Unit: Not habitable
Habitability by Kopparapu: Not habitable
Star Name : K2-398
Alternate Name : EPIC 248463350
Star Distance(LY) : 1979.7
Stellar Radius(Rsun) : 1.2 (Rsun Measured)
Stellar Mass(Msun) : 0.9 (Msun Measured) 1.0 (Msun Estimated)
Star Age : 0.0 (GY)
Temperature : 5946 (K)
Spectral type : G0V
UV portion[%]: 0.3
Visible portion[%]: 1.5
IR portion[%]: 98.2
Metalicity : -0.3
Absolute Magnitude: 4.2
Apparent Magnitude: 13.2
Right Ascension(RA) 161.7350
Declination (DEC) 1.9367
Hubble Space Telescope Guide Star Catalog (GSC) ID
Discovered by
Discovery Paper - Authors
Discovery Paper - Title
Discovery Paper - Journal
Discovery Paper - URL
SIMBAD LINK
Open Exoplanet Database Link
K2-398 c
K2-398 c

  • K2-398 c is an exoplanet orbiting the star K2-398, located about 1979.7 light-years (607.0 pc) away from Solar System. Its discovery was publicly announced on 2022.
  • The host star K2-398 has apparent magnitude of 13.2, with absolute magnitude of 4.2.
  • It is 0.9 times more massive and 1.2 times bigger compared with our Sun. The surface temperature is 5946 with its spectral types of G0V
  • In this planetary system, the extrasolar planet K2-398 c orbits around the star K2-398 every 18.8 days with its orbital distance of 0.14 AU ( 20375230.0 km)
  • (Projected orbit of K2-398 c around its host star K2-398)


  • The Star K2-398 's habitable zone is located at the following distance
  • Inner Boundary (the orbital distance at Venus's Equivalent Radiation ) : 0.949 AU ( 141964327.2 km)
  • Earth Boundary (the orbital distance at Earth's Equivalent Radiation) : 1.312 AU ( 196231799.9 km)
  • Outer Boundary (the orbital distance at Mars's Equivalent Radiation) : 1.999 AU ( 299013837.1 km)
  • Snow Line (the orbital distance at Snow Line Equivalent Radiation) : 2.941 AU ( 440011960.2 km)
  • Radiation at Planetary Boundary of K2-398 c : 126850.69 W/m2

    (Habitable zone calculated based on SEAU(Solar Equivalent Astronomical Unit) around the star K2-398)



  • Kopparapu Recent Venus for Star K2-398 distance : 0.974 AU
  • Kopparapu Runaway Greenhouse for Earth-sized planet for Star K2-398 distance : 1.233 AU
  • Kopparapu Runaway Greenhouse for Super-Earth-sized planet for Star K2-398 distance : 1.191 AU
  • Kopparapu Runaway Greenhouse for Mars-sized planet for Star K2-398 distance : 1.305 AU
  • Kopparapu Outer Boundary for Maximum Greenhouse for Star K2-398 distance : 2.168 AU
  • Kopparapu Outer Boundary for Early Mars for Star K2-398 distance : 2.287 AU

    (Habitable zone calculated based on Kopparapu et al.(2013) around the star K2-398)



  • Original Kopparapu Recent Venus for Star K2-398 distance : 0.978 AU
  • Original Kopparapu Runaway Greenhouse for Star K2-398 distance : 1.266 AU
  • Original Kopparapu Moist Greenhouse for Star K2-398 distance : 1.294 AU
  • Original Kopparapu Outer Boundary for Maximum Greenhouse for Star K2-398 distance : 2.206 AU
  • Original Kopparapu Outer Boundary for Early Mars for Star K2-398 distance : 2.295 AU

    (Habitable zone calculated based on Kopparapu et al.(Original) around the star K2-398)



    (Position in Stellar Map of star K2-398 and its Exoplanet K2-398 c)



    (Zoomed position in Stellar Map of star K2-398 and its Exoplanet K2-398 c (zoom level 3))

    (Synthetic Spectrum of star K2-398*)
    *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