Imaginary Picture of K2-221 b

Display orbital revolution of K2-221 b around the hoststar K2-221
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Exoplanet Name : K2-221 b
Alternate Name : "2MASS J01063719+1011231 b, EPIC 220650439 b, EPIC 220650439.01, WISE J010637.20+101123.0 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) 0.0352 (AU Est.)
Eccentricity : 0.0000
Orbital Period(Yrs) 0.0066
Orbital Period(Observed/Estimated) 2.40 (Days Obs.) 0.00 (Days Est.)
Surface Gravity (G Earth) 1.5131
Star Radiation at Atmospheric Boundary: 954107.4 (W/m2)
Measured Temperature (K) 0.0 (K)
Blackbody T 0.1(K) 1394.9 (K)
Blackbody T 0.3(K) 1310.0 (K)
Blackbody T 0.7(K) 1059.9 (K)
Tidally Locked Blackbody T 0.1(K) 1658.8 (K)
Tidally Locked Blackbody T 0.3(K) 1557.8 (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 : K2-221
Alternate Name : "2MASS J01063719+1011231, EPIC 220650439, WISE J010637.20+101123.0"
Star Distance(LY) : 1015.8
Stellar Radius(Rsun) : 0.9 (Rsun Measured)
Stellar Mass(Msun) : 1.0 (Msun Measured) 1.0 (Msun Estimated)
Star Age : 0.0 (GY)
Temperature : 5716 (K)
Spectral type : G4
UV portion[%]: 7.6
Visible portion[%]: 44.5
IR portion[%]: 47.9
Metalicity : 0.1
Absolute Magnitude: 3.8
Apparent Magnitude: 11.2
Right Ascension(RA) 16.6550
Declination (DEC) 10.1897
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=K2-221+&submit=SIMBAD+search
Open Exoplanet Database Link
K2-221 b
K2-221 b

  • K2-221 b is an exoplanet orbiting the star K2-221, located about 1015.8 light-years (311.4 pc) away from Solar System. Its discovery was publicly announced on 2018.
  • The host star K2-221 has apparent magnitude of 11.2, with absolute magnitude of 3.8.
  • It is 1.0 times more massive and 0.9 times bigger compared with our Sun. The surface temperature is 5716 with its spectral types of G4
  • In this planetary system, the extrasolar planet K2-221 b orbits around the star K2-221 every 2.4 days with its orbital distance of 0.04 AU ( 5264258.8 km)
  • (Projected orbit of K2-221 b around its host star K2-221)


  • The Star K2-221 's habitable zone is located at the following distance
  • Inner Boundary (the orbital distance at Venus's Equivalent Radiation ) : 0.672 AU ( 100592628.9 km)
  • Earth Boundary (the orbital distance at Earth's Equivalent Radiation) : 0.929 AU ( 139045301.1 km)
  • Outer Boundary (the orbital distance at Mars's Equivalent Radiation) : 1.416 AU ( 211874268.2 km)
  • Snow Line (the orbital distance at Snow Line Equivalent Radiation) : 2.084 AU ( 311782267.2 km)
  • Radiation at Planetary Boundary of K2-221 b : 954107.40 W/m2

    (Habitable zone calculated based on SEAU(Solar Equivalent Astronomical Unit) around the star K2-221)



  • Kopparapu Recent Venus for Star K2-221 distance : 0.700 AU
  • Kopparapu Runaway Greenhouse for Earth-sized planet for Star K2-221 distance : 0.886 AU
  • Kopparapu Runaway Greenhouse for Super-Earth-sized planet for Star K2-221 distance : 0.856 AU
  • Kopparapu Runaway Greenhouse for Mars-sized planet for Star K2-221 distance : 0.938 AU
  • Kopparapu Outer Boundary for Maximum Greenhouse for Star K2-221 distance : 1.567 AU
  • Kopparapu Outer Boundary for Early Mars for Star K2-221 distance : 1.653 AU

    (Habitable zone calculated based on Kopparapu et al.(2013) around the star K2-221)



  • Original Kopparapu Recent Venus for Star K2-221 distance : 0.700 AU
  • Original Kopparapu Runaway Greenhouse for Star K2-221 distance : 0.910 AU
  • Original Kopparapu Moist Greenhouse for Star K2-221 distance : 0.926 AU
  • Original Kopparapu Outer Boundary for Maximum Greenhouse for Star K2-221 distance : 1.594 AU
  • Original Kopparapu Outer Boundary for Early Mars for Star K2-221 distance : 1.658 AU

    (Habitable zone calculated based on Kopparapu et al.(Original) around the star K2-221)



    (Position in Stellar Map of star K2-221 and its Exoplanet K2-221 b)



    (Zoomed position in Stellar Map of star K2-221 and its Exoplanet K2-221 b (zoom level 3))

    (Synthetic Spectrum of star K2-221*)
    *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