Imaginary Picture of Kepler-1821 b

Display orbital revolution of Kepler-1821 b around the hoststar Kepler-1821
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Exoplanet Name : Kepler-1821 b
Alternate Name : "KOI-2310 b, KOI-2310.01"
Status : Confirmed
Radius (Rjup / Re): 0.2312 (Rjup) 2.5920 (Rearth)
Mass (Mjup / Me): 0.0201 (Mjup) 6.3972 (Mearth)
Semi Major Axis / Orbital Distance Calculated 0.1244 (AU) 0.1244 (AU Est.)
Eccentricity : 0.0000
Orbital Period(Yrs) 0.0451
Orbital Period(Observed/Estimated) 16.46 (Days Obs.) 16.27 (Days Est.)
Surface Gravity (G Earth) 0.9522
Star Radiation at Atmospheric Boundary: 66144.7 (W/m2)
Measured Temperature (K) 0.0 (K)
Blackbody T 0.1(K) 715.8 (K)
Blackbody T 0.3(K) 672.2 (K)
Blackbody T 0.7(K) 543.9 (K)
Tidally Locked Blackbody T 0.1(K) 851.2 (K)
Tidally Locked Blackbody T 0.3(K) 799.4 (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 : Kepler-1821
Alternate Name : "KIC 11718144, KOI-2310"
Star Distance(LY) : 2608.3
Stellar Radius(Rsun) : 0.9 (Rsun Measured)
Stellar Mass(Msun) : 1.0 (Msun Measured) 0.9 (Msun Estimated)
Star Age : 0.4 (GY)
Temperature : 5524 (K)
Spectral type : G5V
UV portion[%]: 7.0
Visible portion[%]: 43.4
IR portion[%]: 49.6
Metalicity : 0.1
Absolute Magnitude: 5.3
Apparent Magnitude: 14.8
Right Ascension(RA) 294.5254
Declination (DEC) 49.8725
Hubble Space Telescope Guide Star Catalog (GSC) ID
Discovered by
Discovery Paper - Authors
Discovery Paper - Title
Discovery Paper - Journal
Discovery Paper - URL
SIMBAD LINK
Open Exoplanet Database Link
Kepler-1821 b
Kepler-1821 b

  • Kepler-1821 b is an exoplanet orbiting the star Kepler-1821, located about 2608.3 light-years (799.7 pc) away from Solar System. Its discovery was publicly announced on 2017.
  • The host star Kepler-1821 has apparent magnitude of 14.8, with absolute magnitude of 5.3.
  • It is 1.0 times more massive and 0.9 times bigger compared with our Sun. The surface temperature is 5524 with its spectral types of G5V
  • In this planetary system, the extrasolar planet Kepler-1821 b orbits around the star Kepler-1821 every 16.5 days with its orbital distance of 0.12 AU ( 18609975.1 km)
  • (Projected orbit of Kepler-1821 b around its host star Kepler-1821)


  • The Star Kepler-1821 's habitable zone is located at the following distance
  • Inner Boundary (the orbital distance at Venus's Equivalent Radiation ) : 0.626 AU ( 93631871.0 km)
  • Earth Boundary (the orbital distance at Earth's Equivalent Radiation) : 0.865 AU ( 129423714.6 km)
  • Outer Boundary (the orbital distance at Mars's Equivalent Radiation) : 1.318 AU ( 197213099.6 km)
  • Snow Line (the orbital distance at Snow Line Equivalent Radiation) : 1.940 AU ( 290207715.4 km)
  • Radiation at Planetary Boundary of Kepler-1821 b : 66144.73 W/m2

    (Habitable zone calculated based on SEAU(Solar Equivalent Astronomical Unit) around the star Kepler-1821)



  • Kopparapu Recent Venus for Star Kepler-1821 distance : 0.658 AU
  • Kopparapu Runaway Greenhouse for Earth-sized planet for Star Kepler-1821 distance : 0.834 AU
  • Kopparapu Runaway Greenhouse for Super-Earth-sized planet for Star Kepler-1821 distance : 0.805 AU
  • Kopparapu Runaway Greenhouse for Mars-sized planet for Star Kepler-1821 distance : 0.883 AU
  • Kopparapu Outer Boundary for Maximum Greenhouse for Star Kepler-1821 distance : 1.483 AU
  • Kopparapu Outer Boundary for Early Mars for Star Kepler-1821 distance : 1.565 AU

    (Habitable zone calculated based on Kopparapu et al.(2013) around the star Kepler-1821)



  • Original Kopparapu Recent Venus for Star Kepler-1821 distance : 0.656 AU
  • Original Kopparapu Runaway Greenhouse for Star Kepler-1821 distance : 0.858 AU
  • Original Kopparapu Moist Greenhouse for Star Kepler-1821 distance : 0.868 AU
  • Original Kopparapu Outer Boundary for Maximum Greenhouse for Star Kepler-1821 distance : 1.509 AU
  • Original Kopparapu Outer Boundary for Early Mars for Star Kepler-1821 distance : 1.569 AU

    (Habitable zone calculated based on Kopparapu et al.(Original) around the star Kepler-1821)



    (Position in Stellar Map of star Kepler-1821 and its Exoplanet Kepler-1821 b)



    (Zoomed position in Stellar Map of star Kepler-1821 and its Exoplanet Kepler-1821 b (zoom level 3))

    (Synthetic Spectrum of star Kepler-1821*)
    *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