Key parameters at a glance
- A radius of 12.12 Earth radii
- A mass of 295.90 Earth masses
- Surface gravity around 2.02 g
- An orbital period of 2.152 days
- Semi-major axis 0.0314 AU
- Equilibrium temperature 1,311 K (1038 °C)
- Distance from Earth 499.81 light-years
- Earth Similarity Index 0.109
- Travel time at Voyager 1 speed 8,814,113 years
- Almost certainly tidally locked to its host star given the close orbit
WASP-2 b Planet Profile
Physical Specs
Classification
Planet Type
Gas Giant
Discovery
Size rank in cohort
Rank by radius
#1447of 1771
top 81.6%
This planet
12.12R⊕
Gas Giant median
13.52R⊕
Nearest-size peers
| Metric | Earth | WASP-2 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 12.12 | 11.21 |
| Mass (M⊕) | 1.00 | 295.90 | 317.83 |
| Density (g/cm³) | 5.51 | 0.91 | 1.33 |
| Surface Gravity (g) | 1.00 | 2.02 | 2.53 |
| Insolation (S⊕) | 1.00 | 492.00 | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Best measured mass | 295.900 M⊕ | Direct mass measurement (not derived). |
| Minimum mass (M sin i) | 294.628 M⊕ | Lower bound from radial-velocity fitting. |
| Computed mass | 295.996 M⊕ | Model-computed mass (e.g. from mass-radius relation). |
Star Catalogue Identifiers
TIC
TIC 374530847
Gaia DR2
Gaia DR2 1748596020745038208
Gaia DR3
Gaia DR3 1748596020745038208
System
WASP-2
Percentile among Gas Giant cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 2.15 Earth days (0.6% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0314 AU.
Transit Fingerprint
Depth
1.646 %
Duration
1.788 h
Impact parameter b
0.749
Rp / R★
0.128310
Transit midpoint (BJD)
2,458,339.0034
Photometric dip
Transit produces a flux drop of 16,460 ppm lasting ≈ 1.79 h.
Extended Orbital Architecture
Planet / star radius ratio
0.128310
Semi-major axis / stellar radius
7.810
Impact parameter (b)
0.749
RV semi-amplitude (K)
157.000 m/s
Transit mid-time (BJD)
2,458,339.0034
Long. of periastron (ω)
267.00°
Sky-projected obliquity (λ)
-153.00°
True obliquity (ψ)
89.80°
Angular separation (arcsec)
0.20500
Eq. Temperature
1,311K
(1038 °C)
Insolation (S⊕)
492.00
Earth = 1.00
Earth Similarity (ESI)
0.109
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
Collier Cameron et al. 2007Instrument
iKon-L CCD Camera
Publication
2007-03
Observation locale
Ground
Discovery cohort
Planets confirmed in 2007 at SuperWASP (3 shown).
Host System: WASP-2
Spectral Class
K-type orange
Effective Temperature
5,180 K — cooler than the Sun (5,778 K)
Estimated Age
8.20 Gyr — older than the Sun (4.6 Gyr)
Stellar Radius
0.866 R☉
Stellar Mass
0.895 M☉
Metallicity [Fe/H]
0.12
Extended Stellar Properties
Surface gravity (log g)
4.514 dex
Stellar density
1.940 g/cm³
Systemic radial velocity
-27.87 km/s
Rotational v·sin i
0.99 km/s
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 11 bands
Astrometric Data
Parallax
6.498 mas
Total Proper Motion
48.643 mas/yr
PM Right Ascension
5.94 mas/yr
PM Declination
-48.28 mas/yr
Galactic Cartesian (pc)
x = 0.608 · y = -0.786 · z = 0.112
Equatorial (J2000)
RA 307.72556° · Dec 6.42933°
Galactic ℓ, b
50.774° · -18.713°
Ecliptic λ, β
311.942° · 24.543°
HTM-20 index
-1060153648
Observation Record
Photometric series
20
RV measurements
1
Transmission spectra
1
Emission spectra
2
Archive notes
7
Similar Worlds
Kepler-428 b
Gas Giant · K-type orange
Radius 12.11 R⊕ · 2,238.4 ly
WASP-10 b
Gas Giant · K-type orange
Radius 12.11 R⊕ · 459.9 ly
HD 184010 b
Gas Giant · K-type orange
Radius 12.10 R⊕ · 198.3 ly
tau Gem b
Gas Giant · K-type orange
Radius 12.10 R⊕ · 367.0 ly
KIC 3526061 b
Gas Giant · K-type orange
Radius 12.10 R⊕ · 1,308.6 ly
HIP 948 b
Gas Giant · K-type orange
Radius 12.10 R⊕ · 113.7 ly