Imaginary Picture of HD 20794 d

Display orbital revolution of HD 20794 d around the hoststar HD 20794
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Exoplanet Name : HD 20794 d
Alternate Name : "82 Eri d, e Eri d"
Status : Confirmed
Radius (Rjup / Re): 0.1246 (Rjup) 1.3971 (Rearth)
Mass (Mjup / Me): 0.0111 (Mjup) 3.5228 (Mearth)
Semi Major Axis / Orbital Distance Calculated 0.3640 (AU) 0.3640 (AU Est.)
Eccentricity : 0.2500
Orbital Period(Yrs) 0.2434
Orbital Period(Observed/Estimated) 88.90 (Days Obs.) 88.96 (Days Est.)
Surface Gravity (G Earth) 1.8047
Star Radiation at Atmospheric Boundary: 6810.5 (W/m2)
Measured Temperature (K) 0.0 (K)
Blackbody T 0.1(K) 405.4 (K)
Blackbody T 0.3(K) 380.8 (K)
Blackbody T 0.7(K) 308.1 (K)
Tidally Locked Blackbody T 0.1(K) 482.2 (K)
Tidally Locked Blackbody T 0.3(K) 452.8 (K)
Size Class: super-Earth-size
Mass Class:
Detection Type : Radial Velocity
Mass Detection : Radial Velocity
Radius Detection :
Habitability by Solar Eq. Astronomical Unit: Not habitable
Habitability by Kopparapu: Not habitable
Star Name : HD 20794
Alternate Name :
Star Distance(LY) : 19.8
Stellar Radius(Rsun) : 0.9 (Rsun Measured)
Stellar Mass(Msun) : 0.8 (Msun Measured) 0.8 (Msun Estimated)
Star Age : 14.0 (GY)
Temperature : 5490 (K)
Spectral type : G8V
UV portion[%]: 6.8
Visible portion[%]: 43.1
IR portion[%]: 50.0
Metalicity : -0.4
Absolute Magnitude: 5.3
Apparent Magnitude: 4.3
Right Ascension(RA) 49.9819
Declination (DEC) -43.0697
Hubble Space Telescope Guide Star Catalog (GSC) ID
Discovered by
Discovery Paper - Authors 0
Discovery Paper - Title
Discovery Paper - Journal 0
Discovery Paper - URL 0
SIMBAD LINK http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+20794+&submit=SIMBAD+search
Open Exoplanet Database Link http://www.openexoplanetcatalogue.com/planet/HD%2020794%20d/
HD 20794 d
HD 20794 d

  • HD 20794 d is an exoplanet orbiting the star HD 20794, located about 19.8 light-years ( 6.1 pc) away from Solar System. Its discovery was publicly announced on 2011.
  • The host star HD 20794 has apparent magnitude of 4.3, with absolute magnitude of 5.3.
  • It is 0.8 times more massive and 0.9 times bigger compared with our Sun. The surface temperature is 5490 with its spectral types of G8V
  • In this planetary system, the extrasolar planet HD 20794 d orbits around the star HD 20794 every 88.9 days with its orbital distance of 0.36 AU ( 54453624.9 km)
  • (Projected orbit of HD 20794 d around its host star HD 20794)


  • The Star HD 20794 's habitable zone is located at the following distance
  • Inner Boundary (the orbital distance at Venus's Equivalent Radiation ) : 0.588 AU ( 87911423.2 km)
  • Earth Boundary (the orbital distance at Earth's Equivalent Radiation) : 0.812 AU ( 121516560.8 km)
  • Outer Boundary (the orbital distance at Mars's Equivalent Radiation) : 1.238 AU ( 185164347.2 km)
  • Snow Line (the orbital distance at Snow Line Equivalent Radiation) : 1.821 AU ( 272477448.4 km)
  • Radiation at Planetary Boundary of HD 20794 d : 6810.46 W/m2

    (Habitable zone calculated based on SEAU(Solar Equivalent Astronomical Unit) around the star HD 20794)



  • Kopparapu Recent Venus for Star HD 20794 distance : 0.619 AU
  • Kopparapu Runaway Greenhouse for Earth-sized planet for Star HD 20794 distance : 0.784 AU
  • Kopparapu Runaway Greenhouse for Super-Earth-sized planet for Star HD 20794 distance : 0.758 AU
  • Kopparapu Runaway Greenhouse for Mars-sized planet for Star HD 20794 distance : 0.831 AU
  • Kopparapu Outer Boundary for Maximum Greenhouse for Star HD 20794 distance : 1.397 AU
  • Kopparapu Outer Boundary for Early Mars for Star HD 20794 distance : 1.473 AU

    (Habitable zone calculated based on Kopparapu et al.(2013) around the star HD 20794)



  • Original Kopparapu Recent Venus for Star HD 20794 distance : 0.617 AU
  • Original Kopparapu Runaway Greenhouse for Star HD 20794 distance : 0.807 AU
  • Original Kopparapu Moist Greenhouse for Star HD 20794 distance : 0.816 AU
  • Original Kopparapu Outer Boundary for Maximum Greenhouse for Star HD 20794 distance : 1.421 AU
  • Original Kopparapu Outer Boundary for Early Mars for Star HD 20794 distance : 1.478 AU

    (Habitable zone calculated based on Kopparapu et al.(Original) around the star HD 20794)



    (Position in Stellar Map of star HD 20794 and its Exoplanet HD 20794 d)



    (Zoomed position in Stellar Map of star HD 20794 and its Exoplanet HD 20794 d (zoom level 3))

    (Synthetic Spectrum of star HD 20794*)
    *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