Imaginary Picture of K2-9 b

Display orbital revolution of K2-9 b around the hoststar K2-9
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Exoplanet Name : K2-9 b
Alternate Name : "EPIC 201465501 b, 2MASS J11450348+0000190 b, EPIC 201465501
Radius (Rjup / Re): 0.2010 (Rjup) 2.2530 (Rearth)
Mass (Mjup / Me): 0.0177 (Mjup) 5.6154 (Mearth)
Semi Major Axis / Orbital Distance Calculated 0.0910 (AU) 0.0910 (AU Est.)
Eccentricity : 0.0000
Orbital Period(Yrs) 0.0505
Orbital Period(Observed/Estimated) 18.45 (Days Obs.) 18.31 (Days Est.)
Surface Gravity (G Earth) 1.1063
Star Radiation at Atmospheric Boundary: 1879.5 (W/m2)
Measured Temperature (K) 0.0 (K)
Blackbody T 0.1(K) 293.9 (K)
Blackbody T 0.3(K) 276.0 (K)
Blackbody T 0.7(K) 223.3 (K)
Tidally Locked Blackbody T 0.1(K) 349.5 (K)
Tidally Locked Blackbody T 0.3(K) 328.2 (K)
Size Class: sub-Neptune-size
Mass Class:
Detection Type : Primary Transit
Mass Detection :
Radius Detection : Primary Transit
Habitability by Solar Eq. Astronomical Unit: Habitable
Habitability by Kopparapu: Not habitable
Star Name : K2-9
Alternate Name : "EPIC 201465501, 2MASS J11450348+0000190, WISE J114503.35+000019FL_  6?
Star Distance(LY) : 271.2
Stellar Radius(Rsun) : 0.3 (Rsun Measured)
Stellar Mass(Msun) : 0.3 (Msun Measured) 0.3 (Msun Estimated)
Star Age : 1.0 (GY)
Temperature : 3390 (K)
Spectral type : M2.5 V
UV portion[%]: 0.3
Visible portion[%]: 12.2
IR portion[%]: 87.5
Metalicity : -0.2
Absolute Magnitude: 7.9
Apparent Magnitude: 12.5
Right Ascension(RA) 176.2645
Declination (DEC) 0.1012
Hubble Space Telescope Guide Star Catalog (GSC) ID
Discovered by
Discovery Paper - Authors
Discovery Paper - Title
Discovery Paper - Journal 0
Discovery Paper - URL 0
SIMBAD LINK http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=K2-9+&submit=SIMBAD+search
Open Exoplanet Database Link
K2-9 b
K2-9 b

  • K2-9 b is an exoplanet orbiting the star K2-9, located about 271.2 light-years (83.2 pc) away from Solar System. Its discovery was publicly announced on 2015.
  • The host star K2-9 has apparent magnitude of 12.5, with absolute magnitude of 7.9.
  • It is 0.3 times more massive and 0.3 times bigger compared with our Sun. The surface temperature is 3390 with its spectral types of M2.5 V
  • In this planetary system, the extrasolar planet K2-9 b orbits around the star K2-9 every 18.4 days with its orbital distance of 0.09 AU ( 13613406.2 km)
  • (Projected orbit of K2-9 b around its host star K2-9)


  • The Star K2-9 's habitable zone is located at the following distance
  • Inner Boundary (the orbital distance at Venus's Equivalent Radiation ) : 0.077 AU ( 11545671.7 km)
  • Earth Boundary (the orbital distance at Earth's Equivalent Radiation) : 0.107 AU ( 15959135.5 km)
  • Outer Boundary (the orbital distance at Mars's Equivalent Radiation) : 0.163 AU ( 24318190.7 km)
  • Snow Line (the orbital distance at Snow Line Equivalent Radiation) : 0.239 AU ( 35785283.0 km)
  • Radiation at Planetary Boundary of K2-9 b : 1879.51 W/m2

    (Habitable zone calculated based on SEAU(Solar Equivalent Astronomical Unit) around the star K2-9)



  • Kopparapu Recent Venus for Star K2-9 distance : 0.087 AU
  • Kopparapu Runaway Greenhouse for Earth-sized planet for Star K2-9 distance : 0.110 AU
  • Kopparapu Runaway Greenhouse for Super-Earth-sized planet for Star K2-9 distance : 0.107 AU
  • Kopparapu Runaway Greenhouse for Mars-sized planet for Star K2-9 distance : 0.117 AU
  • Kopparapu Outer Boundary for Maximum Greenhouse for Star K2-9 distance : 0.216 AU
  • Kopparapu Outer Boundary for Early Mars for Star K2-9 distance : 0.228 AU

    (Habitable zone calculated based on Kopparapu et al.(2013) around the star K2-9)



  • Original Kopparapu Recent Venus for Star K2-9 distance : 0.087 AU
  • Original Kopparapu Runaway Greenhouse for Star K2-9 distance : 0.114 AU
  • Original Kopparapu Moist Greenhouse for Star K2-9 distance : 0.115 AU
  • Original Kopparapu Outer Boundary for Maximum Greenhouse for Star K2-9 distance : 0.220 AU
  • Original Kopparapu Outer Boundary for Early Mars for Star K2-9 distance : 0.228 AU

    (Habitable zone calculated based on Kopparapu et al.(Original) around the star K2-9)



    (Position in Stellar Map of star K2-9 and its Exoplanet K2-9 b)



    (Zoomed position in Stellar Map of star K2-9 and its Exoplanet K2-9 b (zoom level 3))

    (Synthetic Spectrum of star K2-9*)
    *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