Key parameters at a glance
- A radius of 11.99 Earth radii
- A mass of 947.13 Earth masses
- Surface gravity around 6.58 g
- An orbital period of 54.189 days
- Semi-major axis 0.3130 AU
- Equilibrium temperature 688 K (415 °C)
- Distance from Earth 1,248.84 light-years
- Earth Similarity Index 0.253
- Travel time at Voyager 1 speed 22,023,377 years
NGTS-20 b Planet Profile
Physical Specs
Classification
Planet Type
Gas Giant
Discovery
Size rank in cohort
Rank by radius
#1514of 1771
top 85.4%
This planet
11.99R⊕
Gas Giant median
13.52R⊕
Nearest-size peers
| Metric | Earth | NGTS-20 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 11.99 | 11.21 |
| Mass (M⊕) | 1.00 | 947.13 | 317.83 |
| Density (g/cm³) | 5.51 | 3.02 | 1.33 |
| Surface Gravity (g) | 1.00 | 6.58 | 2.53 |
| Insolation (S⊕) | 1.00 | 6.76 | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Best measured mass | 947.129 M⊕ | Direct mass measurement (not derived). |
Star Catalogue Identifiers
TIC
TIC 257527578
Gaia DR2
Gaia DR2 5078704372599743104
Gaia DR3
Gaia DR3 5078704372599743104
System
NGTS-20
Percentile among Gas Giant cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 54.19 Earth days (14.8% of a terrestrial year) on a highly eccentric trajectory at a mean orbital distance of 0.3130 AU.
Transit Fingerprint
Depth
0.371 %
Duration
4.550 h
Impact parameter b
0.846
Rp / R★
0.061800
Transit midpoint (BJD)
2,458,432.9798
Photometric dip
Transit produces a flux drop of 3,708 ppm lasting ≈ 4.55 h.
Extended Orbital Architecture
Planet / star radius ratio
0.061800
Impact parameter (b)
0.846
RV semi-amplitude (K)
137.000 m/s
Transit mid-time (BJD)
2,458,432.9798
Long. of periastron (ω)
66.10°
Angular separation (arcsec)
0.81700
Eq. Temperature
688K
(415 °C)
Insolation (S⊕)
6.76
Earth = 1.00
Earth Similarity (ESI)
0.253
0 = alien, 1 = Earth-identical
Inside the inner HZ boundary (too hot for liquid water) — the surface is too hot to retain surface water.
Detection Signatures
Transit photometry
A transit dip has been observed from at least one telescope.
Radial velocity
Stellar wobble has been measured spectroscopically.
Discovery Paper
Primary reference
Ulmer Moll et al. 2022Instrument
TESS CCD Array
Publication
2022-07
Observation locale
Space
Discovery cohort
Planets confirmed in 2022 at Transiting Exoplanet Survey Satellite (TESS) (12 shown).
Host System: NGTS-20
Spectral Class
G-type yellow (Sun-like)
Effective Temperature
5,980 K — hotter than the Sun (5,778 K)
Estimated Age
4.10 Gyr — younger than the Sun (4.6 Gyr)
Stellar Radius
1.780 R☉
Stellar Mass
1.470 M☉
Metallicity [Fe/H]
0.15
Extended Stellar Properties
Surface gravity (log g)
3.800 dex
Stellar density
0.348 g/cm³
Rotational v·sin i
8.00 km/s
Activity index (log R'HK)
-5.010
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 11 bands
Astrometric Data
Parallax
2.583 mas
Total Proper Motion
19.874 mas/yr
PM Right Ascension
19.85 mas/yr
PM Declination
-1.08 mas/yr
Galactic Cartesian (pc)
x = 0.641 · y = 0.671 · z = -0.374
Equatorial (J2000)
RA 46.29264° · Dec -21.93365°
Galactic ℓ, b
210.630° · -59.236°
Ecliptic λ, β
36.052° · -37.549°
HTM-20 index
-499752176
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