Imaginary Picture of Kepler-821 b

Display orbital revolution of Kepler-821 b around the hoststar Kepler-821
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Exoplanet Name : Kepler-821 b
Alternate Name : "2MASS J19022818+3922463 b, K01337.01, KIC 4243911 b, KOI-1337 b, KOI-1337.01, WISE J190228.18+392246.1 b"
Status : Confirmed
Radius (Rjup / Re): 0.1170 (Rjup) 1.3115 (Rearth)
Mass (Mjup / Me): 0.0082 (Mjup) 2.6041 (Mearth)
Semi Major Axis / Orbital Distance Calculated 0.0000 (AU) 0.0286 (AU Est.)
Eccentricity : 0.0000
Orbital Period(Yrs) 0.0053
Orbital Period(Observed/Estimated) 1.92 (Days Obs.) 0.00 (Days Est.)
Surface Gravity (G Earth) 1.5141
Star Radiation at Atmospheric Boundary: 700618.5 (W/m2)
Measured Temperature (K) 0.0 (K)
Blackbody T 0.1(K) 1291.3 (K)
Blackbody T 0.3(K) 1212.6 (K)
Blackbody T 0.7(K) 981.1 (K)
Tidally Locked Blackbody T 0.1(K) 1535.6 (K)
Tidally Locked Blackbody T 0.3(K) 1442.1 (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 : Kepler-821
Alternate Name : "2MASS J19022818+3922463, KIC 4243911, KOI-1337, WISE J190228.18+392246.1"
Star Distance(LY) : 2004.0
Stellar Radius(Rsun) : 0.8 (Rsun Measured)
Stellar Mass(Msun) : 0.8 (Msun Measured) 0.8 (Msun Estimated)
Star Age : 4.8 (GY)
Temperature : 5194 (K)
Spectral type : K0
UV portion[%]: 4.9
Visible portion[%]: 40.0
IR portion[%]: 55.1
Metalicity : -0.0
Absolute Magnitude: 4.5
Apparent Magnitude: 13.4
Right Ascension(RA) 285.6174
Declination (DEC) 39.3795
Hubble Space Telescope Guide Star Catalog (GSC) ID
Discovered by
Discovery Paper - Authors "Timothy D. Morton, Stephen T. Bryson, Jeffrey L. Coughlin, Jason F. Rowe, Ganesh Ravichandran, Erik A. Petigura, Michael R. Haas, and Natalie M. Batalha"
Discovery Paper - Title FALSE POSITIVE PROBABILITIES FOR ALL KEPLER OBJECTS OF INTEREST: 1284 NEWLY VALIDATED PLANETS AND 690 LIKELY FALSE POSITIVES
Discovery Paper - Journal 0
Discovery Paper - URL 0
SIMBAD LINK http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=Kepler-821&submit=SIMBAD+search
Open Exoplanet Database Link http://www.openexoplanetcatalogue.com/planet/Kepler-821%20b/
Kepler-821 b
Kepler-821 b

  • Kepler-821 b is an exoplanet orbiting the star Kepler-821, located about 2004.0 light-years (614.4 pc) away from Solar System. Its discovery was publicly announced on 2016.
  • The host star Kepler-821 has apparent magnitude of 13.4, with absolute magnitude of 4.5.
  • It is 0.8 times more massive and 0.8 times bigger compared with our Sun. The surface temperature is 5194 with its spectral types of K0
  • In this planetary system, the extrasolar planet Kepler-821 b orbits around the star Kepler-821 every 1.9 days with its orbital distance of 0.03 AU ( 4271504.9 km)
  • (Projected orbit of Kepler-821 b around its host star Kepler-821)


  • The Star Kepler-821 's habitable zone is located at the following distance
  • Inner Boundary (the orbital distance at Venus's Equivalent Radiation ) : 0.468 AU ( 69944245.6 km)
  • Earth Boundary (the orbital distance at Earth's Equivalent Radiation) : 0.646 AU ( 96681226.0 km)
  • Outer Boundary (the orbital distance at Mars's Equivalent Radiation) : 0.985 AU ( 147320792.9 km)
  • Snow Line (the orbital distance at Snow Line Equivalent Radiation) : 1.449 AU ( 216789000.4 km)
  • Radiation at Planetary Boundary of Kepler-821 b : 700618.45 W/m2

    (Habitable zone calculated based on SEAU(Solar Equivalent Astronomical Unit) around the star Kepler-821)



  • Kopparapu Recent Venus for Star Kepler-821 distance : 0.501 AU
  • Kopparapu Runaway Greenhouse for Earth-sized planet for Star Kepler-821 distance : 0.634 AU
  • Kopparapu Runaway Greenhouse for Super-Earth-sized planet for Star Kepler-821 distance : 0.613 AU
  • Kopparapu Runaway Greenhouse for Mars-sized planet for Star Kepler-821 distance : 0.672 AU
  • Kopparapu Outer Boundary for Maximum Greenhouse for Star Kepler-821 distance : 1.141 AU
  • Kopparapu Outer Boundary for Early Mars for Star Kepler-821 distance : 1.204 AU

    (Habitable zone calculated based on Kopparapu et al.(2013) around the star Kepler-821)



  • Original Kopparapu Recent Venus for Star Kepler-821 distance : 0.497 AU
  • Original Kopparapu Runaway Greenhouse for Star Kepler-821 distance : 0.653 AU
  • Original Kopparapu Moist Greenhouse for Star Kepler-821 distance : 0.657 AU
  • Original Kopparapu Outer Boundary for Maximum Greenhouse for Star Kepler-821 distance : 1.160 AU
  • Original Kopparapu Outer Boundary for Early Mars for Star Kepler-821 distance : 1.207 AU

    (Habitable zone calculated based on Kopparapu et al.(Original) around the star Kepler-821)



    (Position in Stellar Map of star Kepler-821 and its Exoplanet Kepler-821 b)



    (Zoomed position in Stellar Map of star Kepler-821 and its Exoplanet Kepler-821 b (zoom level 3))

    (Synthetic Spectrum of star Kepler-821*)
    *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