Imaginary Picture of K2-198 b

Display orbital revolution of K2-198 b around the hoststar K2-198
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Exoplanet Name : K2-198 b
Alternate Name : "2MASS J13152252-0627535 b, EPIC 212768333 b, EPIC 212768333.03, TYC 4964-1269-1 b, WISE J131522.49-062753.9 b"
Status : Confirmed
Radius (Rjup / Re): 0.3740 (Rjup) 4.1922 (Rearth)
Mass (Mjup / Me): 0.0513 (Mjup) 16.3037 (Mearth)
Semi Major Axis / Orbital Distance Calculated 0.0908 (AU) 0.0908 (AU Est.)
Eccentricity : 0.0000
Orbital Period(Yrs) 0.0467
Orbital Period(Observed/Estimated) 17.04 (Days Obs.) 11.18 (Days Est.)
Surface Gravity (G Earth) 0.9277
Star Radiation at Atmospheric Boundary: 63356.5 (W/m2)
Measured Temperature (K) 0.0 (K)
Blackbody T 0.1(K) 708.1 (K)
Blackbody T 0.3(K) 665.0 (K)
Blackbody T 0.7(K) 538.0 (K)
Tidally Locked Blackbody T 0.1(K) 842.1 (K)
Tidally Locked Blackbody T 0.3(K) 790.8 (K)
Size Class: Neptune-size
Mass Class:
Detection Type : Primary Transit
Mass Detection :
Radius Detection : Primary Transit
Habitability by Solar Eq. Astronomical Unit: Not habitable
Habitability by Kopparapu: Not habitable
Star Name : K2-198
Alternate Name : "EPIC 212768333, 2MASS J13152252-0627535, TYC 4964-1269-1, WISE J131522.49-062753.9"
Star Distance(LY) : 363.8
Stellar Radius(Rsun) : 0.8 (Rsun Measured)
Stellar Mass(Msun) : 0.8 (Msun Measured) 0.3 (Msun Estimated)
Star Age : 0.0 (GY)
Temperature : 5212 (K)
Spectral type : K0
UV portion[%]: 5.1
Visible portion[%]: 40.3
IR portion[%]: 54.6
Metalicity : 0.0
Absolute Magnitude: 5.8
Apparent Magnitude: 11.0
Right Ascension(RA) 198.8438
Declination (DEC) -6.4649
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=K2-198+&submit=SIMBAD+search
Open Exoplanet Database Link
K2-198 b
K2-198 b

  • K2-198 b is an exoplanet orbiting the star K2-198, located about 363.8 light-years (111.5 pc) away from Solar System. Its discovery was publicly announced on 2018.
  • The host star K2-198 has apparent magnitude of 11.0, with absolute magnitude of 5.8.
  • It is 0.8 times more massive and 0.8 times bigger compared with our Sun. The surface temperature is 5212 with its spectral types of K0
  • In this planetary system, the extrasolar planet K2-198 b orbits around the star K2-198 every 17.0 days with its orbital distance of 0.09 AU ( 13587974.6 km)
  • (Projected orbit of K2-198 b around its host star K2-198)


  • The Star K2-198 's habitable zone is located at the following distance
  • Inner Boundary (the orbital distance at Venus's Equivalent Radiation ) : 0.447 AU ( 66908380.6 km)
  • Earth Boundary (the orbital distance at Earth's Equivalent Radiation) : 0.618 AU ( 92484867.3 km)
  • Outer Boundary (the orbital distance at Mars's Equivalent Radiation) : 0.942 AU ( 140926470.9 km)
  • Snow Line (the orbital distance at Snow Line Equivalent Radiation) : 1.386 AU ( 207379475.5 km)
  • Radiation at Planetary Boundary of K2-198 b : 63356.47 W/m2

    (Habitable zone calculated based on SEAU(Solar Equivalent Astronomical Unit) around the star K2-198)



  • Kopparapu Recent Venus for Star K2-198 distance : 0.479 AU
  • Kopparapu Runaway Greenhouse for Earth-sized planet for Star K2-198 distance : 0.606 AU
  • Kopparapu Runaway Greenhouse for Super-Earth-sized planet for Star K2-198 distance : 0.585 AU
  • Kopparapu Runaway Greenhouse for Mars-sized planet for Star K2-198 distance : 0.642 AU
  • Kopparapu Outer Boundary for Maximum Greenhouse for Star K2-198 distance : 1.090 AU
  • Kopparapu Outer Boundary for Early Mars for Star K2-198 distance : 1.149 AU

    (Habitable zone calculated based on Kopparapu et al.(2013) around the star K2-198)



  • Original Kopparapu Recent Venus for Star K2-198 distance : 0.475 AU
  • Original Kopparapu Runaway Greenhouse for Star K2-198 distance : 0.624 AU
  • Original Kopparapu Moist Greenhouse for Star K2-198 distance : 0.628 AU
  • Original Kopparapu Outer Boundary for Maximum Greenhouse for Star K2-198 distance : 1.108 AU
  • Original Kopparapu Outer Boundary for Early Mars for Star K2-198 distance : 1.153 AU

    (Habitable zone calculated based on Kopparapu et al.(Original) around the star K2-198)



    (Position in Stellar Map of star K2-198 and its Exoplanet K2-198 b)



    (Zoomed position in Stellar Map of star K2-198 and its Exoplanet K2-198 b (zoom level 3))

    (Synthetic Spectrum of star K2-198*)
    *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