Imaginary Picture of GJ 15A c

Display orbital revolution of GJ 15A c around the hoststar GJ 15A
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Exoplanet Name : GJ 15A c
Alternate Name : HD 1326A c
Status : Confirmed
Radius (Rjup / Re): 0.2638 (Rjup) 2.9568 (Rearth)
Mass (Mjup / Me): 0.1130 (Mjup) 35.9270 (Mearth)
Semi Major Axis / Orbital Distance Calculated 5.4000 (AU) 5.4000 (AU Est.)
Eccentricity : 0.2700
Orbital Period(Yrs) 20.6839
Orbital Period(Observed/Estimated) 7555.00 (Days Obs.) 7484.54 (Days Est.)
Surface Gravity (G Earth) 4.1094
Star Radiation at Atmospheric Boundary: 1.0 (W/m2)
Measured Temperature (K) 0.0 (K)
Blackbody T 0.1(K) 44.8 (K)
Blackbody T 0.3(K) 42.1 (K)
Blackbody T 0.7(K) 34.0 (K)
Tidally Locked Blackbody T 0.1(K) 53.3 (K)
Tidally Locked Blackbody T 0.3(K) 50.0 (K)
Size Class: sub-Neptune-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 : GJ 15A
Alternate Name : "HD 1326A, HIP 1475, GX Andromedae, Groombridge 34, M2"
Star Distance(LY) : 11.7
Stellar Radius(Rsun) : 0.4 (Rsun Measured)
Stellar Mass(Msun) : 0.4 (Msun Measured) 0.4 (Msun Estimated)
Star Age : 0.0 (GY)
Temperature : 3567 (K)
Spectral type : M2V
UV portion[%]: 0.3
Visible portion[%]: 13.4
IR portion[%]: 86.3
Metalicity : -0.3
Absolute Magnitude: 10.3
Apparent Magnitude: 8.1
Right Ascension(RA) 4.5954
Declination (DEC) 44.0230
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=GJ+15A&submit=SIMBAD+search
Open Exoplanet Database Link
GJ 15A c
GJ 15A c

  • GJ 15A c is an exoplanet orbiting the star GJ 15A, located about 11.7 light-years ( 3.6 pc) away from Solar System. Its discovery was publicly announced on 2018.
  • The host star GJ 15A has apparent magnitude of 8.1, with absolute magnitude of 10.3.
  • It is 0.4 times more massive and 0.4 times bigger compared with our Sun. The surface temperature is 3567 with its spectral types of M2V
  • In this planetary system, the extrasolar planet GJ 15A c orbits around the star GJ 15A every 7555.0 days with its orbital distance of 5.40 AU ( 807828501.8 km)
  • (Projected orbit of GJ 15A c around its host star GJ 15A)


  • The Star GJ 15A 's habitable zone is located at the following distance
  • Inner Boundary (the orbital distance at Venus's Equivalent Radiation ) : 0.106 AU ( 15929019.3 km)
  • Earth Boundary (the orbital distance at Earth's Equivalent Radiation) : 0.147 AU ( 22018067.5 km)
  • Outer Boundary (the orbital distance at Mars's Equivalent Radiation) : 0.224 AU ( 33550662.2 km)
  • Snow Line (the orbital distance at Snow Line Equivalent Radiation) : 0.330 AU ( 49371269.2 km)
  • Radiation at Planetary Boundary of GJ 15A c : 1.02 W/m2

    (Habitable zone calculated based on SEAU(Solar Equivalent Astronomical Unit) around the star GJ 15A)



  • Kopparapu Recent Venus for Star GJ 15A distance : 0.120 AU
  • Kopparapu Runaway Greenhouse for Earth-sized planet for Star GJ 15A distance : 0.152 AU
  • Kopparapu Runaway Greenhouse for Super-Earth-sized planet for Star GJ 15A distance : 0.147 AU
  • Kopparapu Runaway Greenhouse for Mars-sized planet for Star GJ 15A distance : 0.162 AU
  • Kopparapu Outer Boundary for Maximum Greenhouse for Star GJ 15A distance : 0.295 AU
  • Kopparapu Outer Boundary for Early Mars for Star GJ 15A distance : 0.311 AU

    (Habitable zone calculated based on Kopparapu et al.(2013) around the star GJ 15A)



  • Original Kopparapu Recent Venus for Star GJ 15A distance : 0.119 AU
  • Original Kopparapu Runaway Greenhouse for Star GJ 15A distance : 0.157 AU
  • Original Kopparapu Moist Greenhouse for Star GJ 15A distance : 0.158 AU
  • Original Kopparapu Outer Boundary for Maximum Greenhouse for Star GJ 15A distance : 0.300 AU
  • Original Kopparapu Outer Boundary for Early Mars for Star GJ 15A distance : 0.312 AU

    (Habitable zone calculated based on Kopparapu et al.(Original) around the star GJ 15A)



    (Position in Stellar Map of star GJ 15A and its Exoplanet GJ 15A c)



    (Zoomed position in Stellar Map of star GJ 15A and its Exoplanet GJ 15A c (zoom level 3))

    (Synthetic Spectrum of star GJ 15A*)
    *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