Imaginary Picture of NGTS-18 b

Display orbital revolution of NGTS-18 b around the hoststar NGTS-18
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Exoplanet Name : NGTS-18 b
Alternate Name :
Status : Confirmed
Radius (Rjup / Re): 1.2100 (Rjup) 13.5629 (Rearth)
Mass (Mjup / Me): 0.4090 (Mjup) 130.0366 (Mearth)
Semi Major Axis / Orbital Distance Calculated 0.0448 (AU) 0.0448 (AU Est.)
Eccentricity : 0.0000
Orbital Period(Yrs) 0.0084
Orbital Period(Observed/Estimated) 3.05 (Days Obs.) 3.46 (Days Est.)
Surface Gravity (G Earth) 0.7069
Star Radiation at Atmospheric Boundary: 1172677.8 (W/m2)
Measured Temperature (K) 0.0 (K)
Blackbody T 0.1(K) 1468.7 (K)
Blackbody T 0.3(K) 1379.3 (K)
Blackbody T 0.7(K) 1116.0 (K)
Tidally Locked Blackbody T 0.1(K) 1746.6 (K)
Tidally Locked Blackbody T 0.3(K) 1640.2 (K)
Size Class: Jupiter-size
Mass Class:
Detection Type : Primary Transit
Mass Detection : Radial Velocity
Radius Detection : Primary Transit
Habitability by Solar Eq. Astronomical Unit: Not habitable
Habitability by Kopparapu: Not habitable
Star Name : NGTS-18
Alternate Name :
Star Distance(LY) : 3613.8
Stellar Radius(Rsun) : 1.4 (Rsun Measured)
Stellar Mass(Msun) : 1.0 (Msun Measured) 1.3 (Msun Estimated)
Star Age : 10.8 (GY)
Temperature : 5610 (K)
Spectral type : G5V
UV portion[%]: 7.3
Visible portion[%]: 43.9
IR portion[%]: 48.8
Metalicity : 0.1
Absolute Magnitude: 4.3
Apparent Magnitude: 14.5
Right Ascension(RA) 180.5458
Declination (DEC) -35.5486
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
NGTS-18 b
NGTS-18 b

  • NGTS-18 b is an exoplanet orbiting the star NGTS-18, located about 3613.8 light-years (1108.0 pc) away from Solar System. Its discovery was publicly announced on 2021.
  • The host star NGTS-18 has apparent magnitude of 14.5, with absolute magnitude of 4.3.
  • It is 1.0 times more massive and 1.4 times bigger compared with our Sun. The surface temperature is 5610 with its spectral types of G5V
  • In this planetary system, the extrasolar planet NGTS-18 b orbits around the star NGTS-18 every 3.1 days with its orbital distance of 0.04 AU ( 6701984.6 km)
  • (Projected orbit of NGTS-18 b around its host star NGTS-18)


  • The Star NGTS-18 's habitable zone is located at the following distance
  • Inner Boundary (the orbital distance at Venus's Equivalent Radiation ) : 0.949 AU ( 141978659.1 km)
  • Earth Boundary (the orbital distance at Earth's Equivalent Radiation) : 1.312 AU ( 196251610.4 km)
  • Outer Boundary (the orbital distance at Mars's Equivalent Radiation) : 1.999 AU ( 299044023.8 km)
  • Snow Line (the orbital distance at Snow Line Equivalent Radiation) : 2.942 AU ( 440056381.3 km)
  • Radiation at Planetary Boundary of NGTS-18 b : 1172677.79 W/m2

    (Habitable zone calculated based on SEAU(Solar Equivalent Astronomical Unit) around the star NGTS-18)



  • Kopparapu Recent Venus for Star NGTS-18 distance : 0.994 AU
  • Kopparapu Runaway Greenhouse for Earth-sized planet for Star NGTS-18 distance : 1.258 AU
  • Kopparapu Runaway Greenhouse for Super-Earth-sized planet for Star NGTS-18 distance : 1.215 AU
  • Kopparapu Runaway Greenhouse for Mars-sized planet for Star NGTS-18 distance : 1.332 AU
  • Kopparapu Outer Boundary for Maximum Greenhouse for Star NGTS-18 distance : 2.232 AU
  • Kopparapu Outer Boundary for Early Mars for Star NGTS-18 distance : 2.354 AU

    (Habitable zone calculated based on Kopparapu et al.(2013) around the star NGTS-18)



  • Original Kopparapu Recent Venus for Star NGTS-18 distance : 0.992 AU
  • Original Kopparapu Runaway Greenhouse for Star NGTS-18 distance : 1.294 AU
  • Original Kopparapu Moist Greenhouse for Star NGTS-18 distance : 1.312 AU
  • Original Kopparapu Outer Boundary for Maximum Greenhouse for Star NGTS-18 distance : 2.271 AU
  • Original Kopparapu Outer Boundary for Early Mars for Star NGTS-18 distance : 2.362 AU

    (Habitable zone calculated based on Kopparapu et al.(Original) around the star NGTS-18)



    (Position in Stellar Map of star NGTS-18 and its Exoplanet NGTS-18 b)



    (Zoomed position in Stellar Map of star NGTS-18 and its Exoplanet NGTS-18 b (zoom level 3))

    (Synthetic Spectrum of star NGTS-18*)
    *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