Imaginary Picture of K2-8 b

Display orbital revolution of K2-8 b around the hoststar K2-8
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Exoplanet Name : K2-8 b
Alternate Name : "2MASS J11191047-0017036 b, EPIC 201445392 b, EPIC 201445392.01, WISE J111910.45-001703.8 b"
Status : Confirmed
Radius (Rjup / Re): 0.3190 (Rjup) 3.5757 (Rearth)
Mass (Mjup / Me): 0.0271 (Mjup) 8.6285 (Mearth)
Semi Major Axis / Orbital Distance Calculated 0.0856 (AU) 0.0856 (AU Est.)
Eccentricity : 0.0000
Orbital Period(Yrs) 0.0283
Orbital Period(Observed/Estimated) 10.35 (Days Obs.) 10.36 (Days Est.)
Surface Gravity (G Earth) 0.6749
Star Radiation at Atmospheric Boundary: 51550.9 (W/m2)
Measured Temperature (K) 0.0 (K)
Blackbody T 0.1(K) 672.5 (K)
Blackbody T 0.3(K) 631.6 (K)
Blackbody T 0.7(K) 511.0 (K)
Tidally Locked Blackbody T 0.1(K) 799.8 (K)
Tidally Locked Blackbody T 0.3(K) 751.1 (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 : K2-8
Alternate Name : "EPIC 201445392, 2MASS J11191047-0017036, WISE J111910.45-001703.8"
Star Distance(LY) : 1331.8
Stellar Radius(Rsun) : 0.7 (Rsun Measured)
Stellar Mass(Msun) : 0.8 (Msun Measured) 0.8 (Msun Estimated)
Star Age : 0.0 (GY)
Temperature : 4870 (K)
Spectral type : K3 V
UV portion[%]: 2.7
Visible portion[%]: 35.9
IR portion[%]: 61.4
Metalicity : -0.0
Absolute Magnitude: 6.3
Apparent Magnitude: 14.4
Right Ascension(RA) 169.7937
Declination (DEC) -0.2844
Hubble Space Telescope Guide Star Catalog (GSC) ID
Discovered by
Discovery Paper - Authors "Benjamin T. Montet, Timothy D. Morton, Daniel Foreman-Mackey, John Asher Johnson, David W. Hogg, Brendan P. Bowler, David W. Latham, Allyson Bieryla, Andrew W. Mann, "
Discovery Paper - Title "STELLAR AND PLANETARY PROPERTIES OF K2 CAMPAIGN 1 CANDIDATES AND VALIDATION OF 18 SYSTEMS, INCLUDING A PLANET RECEIVING EARTH-LIKE INSOLATION "
Discovery Paper - Journal 0
Discovery Paper - URL 0
SIMBAD LINK http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=K2-8+&submit=SIMBAD+search
Open Exoplanet Database Link http://www.openexoplanetcatalogue.com/planet/EPIC%20201445392%20b/
K2-8 b
K2-8 b

  • K2-8 b is an exoplanet orbiting the star K2-8, located about 1331.8 light-years (408.3 pc) away from Solar System. Its discovery was publicly announced on 2015.
  • The host star K2-8 has apparent magnitude of 14.4, with absolute magnitude of 6.3.
  • It is 0.8 times more massive and 0.7 times bigger compared with our Sun. The surface temperature is 4870 with its spectral types of K3 V
  • In this planetary system, the extrasolar planet K2-8 b orbits around the star K2-8 every 10.4 days with its orbital distance of 0.09 AU ( 12805577.7 km)
  • (Projected orbit of K2-8 b around its host star K2-8)


  • The Star K2-8 's habitable zone is located at the following distance
  • Inner Boundary (the orbital distance at Venus's Equivalent Radiation ) : 0.380 AU ( 56878450.2 km)
  • Earth Boundary (the orbital distance at Earth's Equivalent Radiation) : 0.526 AU ( 78620882.3 km)
  • Outer Boundary (the orbital distance at Mars's Equivalent Radiation) : 0.801 AU ( 119800825.9 km)
  • Snow Line (the orbital distance at Snow Line Equivalent Radiation) : 1.178 AU ( 176292163.5 km)
  • Radiation at Planetary Boundary of K2-8 b : 51550.94 W/m2

    (Habitable zone calculated based on SEAU(Solar Equivalent Astronomical Unit) around the star K2-8)



  • Kopparapu Recent Venus for Star K2-8 distance : 0.414 AU
  • Kopparapu Runaway Greenhouse for Earth-sized planet for Star K2-8 distance : 0.524 AU
  • Kopparapu Runaway Greenhouse for Super-Earth-sized planet for Star K2-8 distance : 0.506 AU
  • Kopparapu Runaway Greenhouse for Mars-sized planet for Star K2-8 distance : 0.555 AU
  • Kopparapu Outer Boundary for Maximum Greenhouse for Star K2-8 distance : 0.955 AU
  • Kopparapu Outer Boundary for Early Mars for Star K2-8 distance : 1.007 AU

    (Habitable zone calculated based on Kopparapu et al.(2013) around the star K2-8)



  • Original Kopparapu Recent Venus for Star K2-8 distance : 0.409 AU
  • Original Kopparapu Runaway Greenhouse for Star K2-8 distance : 0.540 AU
  • Original Kopparapu Moist Greenhouse for Star K2-8 distance : 0.541 AU
  • Original Kopparapu Outer Boundary for Maximum Greenhouse for Star K2-8 distance : 0.970 AU
  • Original Kopparapu Outer Boundary for Early Mars for Star K2-8 distance : 1.009 AU

    (Habitable zone calculated based on Kopparapu et al.(Original) around the star K2-8)



    (Position in Stellar Map of star K2-8 and its Exoplanet K2-8 b)



    (Zoomed position in Stellar Map of star K2-8 and its Exoplanet K2-8 b (zoom level 3))

    (Synthetic Spectrum of star K2-8*)
    *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