Key parameters at a glance
- A radius of 17.36 Earth radii
- A mass of 151.92 Earth masses
- Surface gravity around 0.50 g
- An orbital period of 3.406 days
- Semi-major axis 0.0466 AU
- Equilibrium temperature 1,424 K (1151 °C)
- Distance from Earth 1,251.88 light-years
- Earth Similarity Index 0.067
- Travel time at Voyager 1 speed 22,076,926 years
WASP-31 b Planet Profile
Physical Specs
Classification
Planet Type
Gas Giant
Discovery
Size rank in cohort
Rank by radius
#98of 1771
top 5.5%
This planet
17.36R⊕
Gas Giant median
13.52R⊕
Nearest-size peers
| Metric | Earth | WASP-31 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 17.36 | 11.21 |
| Mass (M⊕) | 1.00 | 151.92 | 317.83 |
| Density (g/cm³) | 5.51 | 0.17 | 1.33 |
| Surface Gravity (g) | 1.00 | 0.50 | 2.53 |
| Insolation (S⊕) | 1.00 | 970.94 | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Best measured mass | 151.916 M⊕ | Direct mass measurement (not derived). |
Star Catalogue Identifiers
TIC
TIC 437248515
Gaia DR2
Gaia DR2 3545873945303316224
Gaia DR3
Gaia DR3 3545873945303316224
System
WASP-31
Percentile among Gas Giant cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 3.41 Earth days (0.9% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0466 AU.
Transit Fingerprint
Depth
1.615 %
Duration
2.647 h
Impact parameter b
0.770
Rp / R★
0.127100
Transit midpoint (BJD)
2,455,192.6887
Photometric dip
Transit produces a flux drop of 16,150 ppm lasting ≈ 2.65 h.
Extended Orbital Architecture
Planet / star radius ratio
0.127100
Semi-major axis / stellar radius
8.000
Impact parameter (b)
0.770
RV semi-amplitude (K)
59.400 m/s
Transit mid-time (BJD)
2,455,192.6887
Sky-projected obliquity (λ)
2.80°
Angular separation (arcsec)
0.12100
Eq. Temperature
1,424K
(1151 °C)
Insolation (S⊕)
970.94
Earth = 1.00
Earth Similarity (ESI)
0.067
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
Anderson et al. 2011Instrument
iKon-L CCD Camera
Publication
2011-07
Observation locale
Ground
Discovery cohort
Planets confirmed in 2010 at SuperWASP (12 shown).
Host System: WASP-31
Spectral Class
F-type yellow-white
Effective Temperature
6,302 K — hotter than the Sun (5,778 K)
Estimated Age
1.00 Gyr — younger than the Sun (4.6 Gyr)
Stellar Radius
1.252 R☉
Stellar Mass
1.163 M☉
Metallicity [Fe/H]
-0.20
Extended Stellar Properties
Surface gravity (log g)
4.308 dex
Stellar density
0.829 g/cm³
Systemic radial velocity
-0.34 km/s
Rotational v·sin i
7.90 km/s
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 11 bands
Astrometric Data
Parallax
2.577 mas
Total Proper Motion
28.725 mas/yr
PM Right Ascension
-28.71 mas/yr
PM Declination
0.99 mas/yr
Galactic Cartesian (pc)
x = -0.929 · y = 0.173 · z = -0.326
Equatorial (J2000)
RA 169.43886° · Dec -19.05478°
Galactic ℓ, b
274.226° · 38.539°
Ecliptic λ, β
178.203° · -21.620°
HTM-20 index
964819418
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