Imaginary Picture of K2-87 b

Display orbital revolution of K2-87 b around the hoststar K2-87
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Exoplanet Name : K2-87 b
Alternate Name : EPIC 210731500.01
Status : Confirmed
Radius (Rjup / Re): 0.6780 (Rjup) 7.5997 (Rearth)
Mass (Mjup / Me): 0.1192 (Mjup) 37.8982 (Mearth)
Semi Major Axis / Orbital Distance Calculated 0.0940 (AU) 0.0940 (AU Est.)
Eccentricity : 0.0000
Orbital Period(Yrs) 0.0266
Orbital Period(Observed/Estimated) 9.73 (Days Obs.) 9.77 (Days Est.)
Surface Gravity (G Earth) 0.6562
Star Radiation at Atmospheric Boundary: 296735.8 (W/m2)
Measured Temperature (K) 0.0 (K)
Blackbody T 0.1(K) 1041.7 (K)
Blackbody T 0.3(K) 978.2 (K)
Blackbody T 0.7(K) 791.5 (K)
Tidally Locked Blackbody T 0.1(K) 1238.8 (K)
Tidally Locked Blackbody T 0.3(K) 1163.3 (K)
Size Class: sub-Jupiter-size
Mass Class:
Detection Type : Primary Transit
Mass Detection : Theoretical
Radius Detection : Primary Transit
Habitability by Solar Eq. Astronomical Unit: Not habitable
Habitability by Kopparapu: Not habitable
Star Name : K2-87
Alternate Name : "2MASS J04245669+1849387, EPIC 210731500, WISE J042456.71+184938.6"
Star Distance(LY) : 1627.2
Stellar Radius(Rsun) : 1.4 (Rsun Measured)
Stellar Mass(Msun) : 1.2 (Msun Measured) 1.2 (Msun Estimated)
Star Age : 0.0 (GY)
Temperature : 5747 (K)
Spectral type : G3
UV portion[%]: 7.7
Visible portion[%]: 44.6
IR portion[%]: 47.6
Metalicity : 0.3
Absolute Magnitude: 3.3
Apparent Magnitude: 11.8
Right Ascension(RA) 66.2362
Declination (DEC) 18.8274
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=K2-87+&submit=SIMBAD+search
Open Exoplanet Database Link
K2-87 b
K2-87 b

  • K2-87 b is an exoplanet orbiting the star K2-87, located about 1627.2 light-years (498.9 pc) away from Solar System. Its discovery was publicly announced on 2016.
  • The host star K2-87 has apparent magnitude of 11.8, with absolute magnitude of 3.3.
  • It is 1.2 times more massive and 1.4 times bigger compared with our Sun. The surface temperature is 5747 with its spectral types of G3
  • In this planetary system, the extrasolar planet K2-87 b orbits around the star K2-87 every 9.7 days with its orbital distance of 0.09 AU ( 14062199.8 km)
  • (Projected orbit of K2-87 b around its host star K2-87)


  • The Star K2-87 's habitable zone is located at the following distance
  • Inner Boundary (the orbital distance at Venus's Equivalent Radiation ) : 1.002 AU ( 149854069.9 km)
  • Earth Boundary (the orbital distance at Earth's Equivalent Radiation) : 1.385 AU ( 207137486.1 km)
  • Outer Boundary (the orbital distance at Mars's Equivalent Radiation) : 2.110 AU ( 315631689.4 km)
  • Snow Line (the orbital distance at Snow Line Equivalent Radiation) : 3.105 AU ( 464465857.9 km)
  • Radiation at Planetary Boundary of K2-87 b : 296735.81 W/m2

    (Habitable zone calculated based on SEAU(Solar Equivalent Astronomical Unit) around the star K2-87)



  • Kopparapu Recent Venus for Star K2-87 distance : 1.040 AU
  • Kopparapu Runaway Greenhouse for Earth-sized planet for Star K2-87 distance : 1.317 AU
  • Kopparapu Runaway Greenhouse for Super-Earth-sized planet for Star K2-87 distance : 1.272 AU
  • Kopparapu Runaway Greenhouse for Mars-sized planet for Star K2-87 distance : 1.395 AU
  • Kopparapu Outer Boundary for Maximum Greenhouse for Star K2-87 distance : 2.328 AU
  • Kopparapu Outer Boundary for Early Mars for Star K2-87 distance : 2.455 AU

    (Habitable zone calculated based on Kopparapu et al.(2013) around the star K2-87)



  • Original Kopparapu Recent Venus for Star K2-87 distance : 1.041 AU
  • Original Kopparapu Runaway Greenhouse for Star K2-87 distance : 1.354 AU
  • Original Kopparapu Moist Greenhouse for Star K2-87 distance : 1.377 AU
  • Original Kopparapu Outer Boundary for Maximum Greenhouse for Star K2-87 distance : 2.369 AU
  • Original Kopparapu Outer Boundary for Early Mars for Star K2-87 distance : 2.463 AU

    (Habitable zone calculated based on Kopparapu et al.(Original) around the star K2-87)



    (Position in Stellar Map of star K2-87 and its Exoplanet K2-87 b)



    (Zoomed position in Stellar Map of star K2-87 and its Exoplanet K2-87 b (zoom level 3))

    (Synthetic Spectrum of star K2-87*)
    *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