Imaginary Picture of K2-17 b

Display orbital revolution of K2-17 b around the hoststar K2-17
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Exoplanet Name : K2-17 b
Alternate Name : "EPIC 201855371 b, 2MASS J11531915+0624439 b, EPIC 201855371.01, WISE J115319.12+062444.2 b"
Status : Confirmed
Radius (Rjup / Re): 0.1990 (Rjup) 2.2306 (Rearth)
Mass (Mjup / Me): 0.0175 (Mjup) 5.5634 (Mearth)
Semi Major Axis / Orbital Distance Calculated 0.1190 (AU) 0.1190 (AU Est.)
Eccentricity : 0.0000
Orbital Period(Yrs) 0.0492
Orbital Period(Observed/Estimated) 17.97 (Days Obs.) 17.79 (Days Est.)
Surface Gravity (G Earth) 1.1182
Star Radiation at Atmospheric Boundary: 13138.1 (W/m2)
Measured Temperature (K) 0.0 (K)
Blackbody T 0.1(K) 477.8 (K)
Blackbody T 0.3(K) 448.7 (K)
Blackbody T 0.7(K) 363.1 (K)
Tidally Locked Blackbody T 0.1(K) 568.2 (K)
Tidally Locked Blackbody T 0.3(K) 533.6 (K)
Size Class: sub-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 : K2-17
Alternate Name : "EPIC 201855371, 2MASS J11531915+0624439, WISE J115319.12+062444.2"
Star Distance(LY) : 403.0
Stellar Radius(Rsun) : 0.7 (Rsun Measured)
Stellar Mass(Msun) : 0.7 (Msun Measured) 0.7 (Msun Estimated)
Star Age : 0.0 (GY)
Temperature : 4320 (K)
Spectral type : K7
UV portion[%]: 0.9
Visible portion[%]: 27.8
IR portion[%]: 71.2
Metalicity : 0.1
Absolute Magnitude: 5.6
Apparent Magnitude: 11.1
Right Ascension(RA) 178.3298
Declination (DEC) 6.4123
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=K2-17+&submit=SIMBAD+search
Open Exoplanet Database Link
K2-17 b
K2-17 b

  • K2-17 b is an exoplanet orbiting the star K2-17, located about 403.0 light-years (123.6 pc) away from Solar System. Its discovery was publicly announced on 2015.
  • The host star K2-17 has apparent magnitude of 11.1, with absolute magnitude of 5.6.
  • It is 0.7 times more massive and 0.7 times bigger compared with our Sun. The surface temperature is 4320 with its spectral types of K7
  • In this planetary system, the extrasolar planet K2-17 b orbits around the star K2-17 every 18.0 days with its orbital distance of 0.12 AU ( 17802146.6 km)
  • (Projected orbit of K2-17 b around its host star K2-17)


  • The Star K2-17 's habitable zone is located at the following distance
  • Inner Boundary (the orbital distance at Venus's Equivalent Radiation ) : 0.267 AU ( 39918070.6 km)
  • Earth Boundary (the orbital distance at Earth's Equivalent Radiation) : 0.369 AU ( 55177205.4 km)
  • Outer Boundary (the orbital distance at Mars's Equivalent Radiation) : 0.562 AU ( 84077850.3 km)
  • Snow Line (the orbital distance at Snow Line Equivalent Radiation) : 0.827 AU ( 123724239.9 km)
  • Radiation at Planetary Boundary of K2-17 b : 13138.14 W/m2

    (Habitable zone calculated based on SEAU(Solar Equivalent Astronomical Unit) around the star K2-17)



  • Kopparapu Recent Venus for Star K2-17 distance : 0.296 AU
  • Kopparapu Runaway Greenhouse for Earth-sized planet for Star K2-17 distance : 0.375 AU
  • Kopparapu Runaway Greenhouse for Super-Earth-sized planet for Star K2-17 distance : 0.362 AU
  • Kopparapu Runaway Greenhouse for Mars-sized planet for Star K2-17 distance : 0.398 AU
  • Kopparapu Outer Boundary for Maximum Greenhouse for Star K2-17 distance : 0.701 AU
  • Kopparapu Outer Boundary for Early Mars for Star K2-17 distance : 0.740 AU

    (Habitable zone calculated based on Kopparapu et al.(2013) around the star K2-17)



  • Original Kopparapu Recent Venus for Star K2-17 distance : 0.293 AU
  • Original Kopparapu Runaway Greenhouse for Star K2-17 distance : 0.388 AU
  • Original Kopparapu Moist Greenhouse for Star K2-17 distance : 0.387 AU
  • Original Kopparapu Outer Boundary for Maximum Greenhouse for Star K2-17 distance : 0.712 AU
  • Original Kopparapu Outer Boundary for Early Mars for Star K2-17 distance : 0.741 AU

    (Habitable zone calculated based on Kopparapu et al.(Original) around the star K2-17)



    (Position in Stellar Map of star K2-17 and its Exoplanet K2-17 b)



    (Zoomed position in Stellar Map of star K2-17 and its Exoplanet K2-17 b (zoom level 3))

    (Synthetic Spectrum of star K2-17*)
    *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