Key parameters at a glance
- A radius of 12.22 Earth radii
- A mass of 295.58 Earth masses
- Surface gravity around 1.98 g
- An orbital period of 2.500 days
- Semi-major axis 0.0350 AU
- Equilibrium temperature 1,345 K (1072 °C)
- Distance from Earth 1,399.13 light-years
- Earth Similarity Index 0.105
- Travel time at Voyager 1 speed 24,673,673 years
- Almost certainly tidally locked to its host star given the close orbit
NGTS-8 b Planet Profile
Physical Specs
Classification
Planet Type
Gas Giant
Discovery
Size rank in cohort
Rank by radius
#1404of 1771
top 79.2%
This planet
12.22R⊕
Gas Giant median
13.52R⊕
Nearest-size peers
| Metric | Earth | NGTS-8 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 12.22 | 11.21 |
| Mass (M⊕) | 1.00 | 295.58 | 317.83 |
| Density (g/cm³) | 5.51 | 0.89 | 1.33 |
| Surface Gravity (g) | 1.00 | 1.98 | 2.53 |
| Insolation (S⊕) | 1.00 | 503.00 | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Best measured mass | 295.582 M⊕ | Direct mass measurement (not derived). |
Star Catalogue Identifiers
TIC
TIC 102068384
Gaia DR2
Gaia DR2 6840435777723109888
Gaia DR3
Gaia DR3 6840435777723109888
System
NGTS-8
Percentile among Gas Giant cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 2.50 Earth days (0.7% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0350 AU.
Transit Fingerprint
Depth
1.303 %
Duration
2.610 h
Rp / R★
0.114000
Transit midpoint (BJD)
2,457,500.1783
Photometric dip
Transit produces a flux drop of 13,027 ppm lasting ≈ 2.61 h.
Extended Orbital Architecture
Planet / star radius ratio
0.114000
Semi-major axis / stellar radius
7.600
RV semi-amplitude (K)
149.950 m/s
Transit mid-time (BJD)
2,457,500.1783
Angular separation (arcsec)
0.08160
Eq. Temperature
1,345K
(1072 °C)
Insolation (S⊕)
503.00
Earth = 1.00
Earth Similarity (ESI)
0.105
0 = alien, 1 = Earth-identical
Inside the inner HZ boundary (too hot for liquid water) — the dayside is scorched. Close-orbiting tidally-locked around a cool host.
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
Costes et al. 2020Instrument
NGTS CCD array
Publication
2020-01
Observation locale
Ground
Discovery cohort
Planets confirmed in 2019 at Next-Generation Transit Survey (NGTS) (4 shown).
Host System: NGTS-8
Spectral Class
K-type orange
Effective Temperature
5,241 K — cooler than the Sun (5,778 K)
Estimated Age
12.48 Gyr — older than the Sun (4.6 Gyr)
Stellar Radius
0.980 R☉
Stellar Mass
0.890 M☉
Metallicity [Fe/H]
0.24
Extended Stellar Properties
Surface gravity (log g)
4.410 dex
Stellar density
1.232 g/cm³
Rotational v·sin i
3.56 km/s
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 14 bands
Astrometric Data
Parallax
2.303 mas
Total Proper Motion
23.670 mas/yr
PM Right Ascension
21.36 mas/yr
PM Declination
-10.19 mas/yr
Galactic Cartesian (pc)
x = 0.831 · y = -0.500 · z = -0.243
Equatorial (J2000)
RA 328.97592° · Dec -14.06844°
Galactic ℓ, b
41.595° · -47.144°
Ecliptic λ, β
326.248° · -1.384°
HTM-20 index
-1492239860
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