Key parameters at a glance
- A radius of 18.05 Earth radii
- A mass of 355.97 Earth masses
- Surface gravity around 1.09 g
- An orbital period of 4.163 days
- Semi-major axis 0.0640 AU
- Equilibrium temperature 1,410 K (1137 °C)
- Distance from Earth 1,622.22 light-years
- Earth Similarity Index 0.073
- Travel time at Voyager 1 speed 28,607,877 years
NGTS-31 b Planet Profile
Physical Specs
Classification
Planet Type
Gas Giant
Discovery
Size rank in cohort
Rank by radius
#71of 1771
top 4.0%
This planet
18.05R⊕
Gas Giant median
13.52R⊕
Nearest-size peers
| Metric | Earth | NGTS-31 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 18.05 | 11.21 |
| Mass (M⊕) | 1.00 | 355.97 | 317.83 |
| Density (g/cm³) | 5.51 | 0.30 | 1.33 |
| Surface Gravity (g) | 1.00 | 1.09 | 2.53 |
| Insolation (S⊕) | 1.00 | 643.00 | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Best measured mass | 355.968 M⊕ | Direct mass measurement (not derived). |
Star Catalogue Identifiers
TIC
TIC 167714124
Gaia DR2
Gaia DR2 4819647205325461888
Gaia DR3
Gaia DR3 4819647205326045824
System
NGTS-31
Percentile among Gas Giant cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 4.16 Earth days (1.1% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0640 AU.
Transit Fingerprint
Depth
1.287 %
Duration
3.319 h
Impact parameter b
0.630
Rp / R★
0.110000
Transit midpoint (BJD)
2,459,039.1615
Photometric dip
Transit produces a flux drop of 12,870 ppm lasting ≈ 3.32 h.
Extended Orbital Architecture
Planet / star radius ratio
0.110000
Semi-major axis / stellar radius
8.160
Impact parameter (b)
0.630
RV semi-amplitude (K)
146.630 m/s
Transit mid-time (BJD)
2,459,039.1615
Long. of periastron (ω)
90.00°
Angular separation (arcsec)
0.12900
Eq. Temperature
1,410K
(1137 °C)
Insolation (S⊕)
643.00
Earth = 1.00
Earth Similarity (ESI)
0.073
0 = alien, 1 = Earth-identical
Inside the inner HZ boundary (too hot for liquid water) — the dayside is scorched.
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
Vines et al. 2025Instrument
TESS CCD Array
Publication
2025-01
Observation locale
Space
Discovery cohort
Planets confirmed in 2025 at Transiting Exoplanet Survey Satellite (TESS) (12 shown).
Host System: NGTS-31
Spectral Class
G-type yellow (Sun-like)
Effective Temperature
5,710 K — cooler than the Sun (5,778 K)
Estimated Age
9.97 Gyr — older than the Sun (4.6 Gyr)
Stellar Radius
1.700 R☉
Stellar Mass
0.960 M☉
Metallicity [Fe/H]
0.00
Extended Stellar Properties
Surface gravity (log g)
4.430 dex
Stellar density
0.585 g/cm³
Rotational v·sin i
6.10 km/s
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 11 bands
Astrometric Data
Total Proper Motion
6.488 mas/yr
PM Right Ascension
-4.61 mas/yr
PM Declination
-4.56 mas/yr
Galactic Cartesian (pc)
x = 0.130 · y = 0.770 · z = -0.625
Equatorial (J2000)
RA 80.42125° · Dec -38.65683°
Galactic ℓ, b
243.128° · -33.374°
Ecliptic λ, β
74.156° · -61.570°
HTM-20 index
1993908592
Similar Worlds
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Radius 18.06 R⊕ · 2,408.7 ly
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Kepler-447 b
Gas Giant · G-type yellow (Sun-like)
Radius 18.49 R⊕ · 874.2 ly