Key parameters at a glance
- A radius of 15.12 Earth radii
- A mass of 381.39 Earth masses
- Surface gravity around 1.67 g
- An orbital period of 1.338 days
- Semi-major axis 0.0226 AU
- Equilibrium temperature 1,653 K (1380 °C)
- Distance from Earth 871.51 light-years
- Earth Similarity Index 0.074
- Travel time at Voyager 1 speed 15,369,050 years
WASP-4 b Planet Profile
Physical Specs
Classification
Planet Type
Gas Giant
Discovery
Size rank in cohort
Rank by radius
#225of 1771
top 12.6%
This planet
15.12R⊕
Gas Giant median
13.52R⊕
Nearest-size peers
| Metric | Earth | WASP-4 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 15.12 | 11.21 |
| Mass (M⊕) | 1.00 | 381.39 | 317.83 |
| Density (g/cm³) | 5.51 | 0.65 | 1.33 |
| Surface Gravity (g) | 1.00 | 1.67 | 2.53 |
| Insolation (S⊕) | 1.00 | 1,188.62 | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Best measured mass | 381.394 M⊕ | Direct mass measurement (not derived). |
Star Catalogue Identifiers
TIC
TIC 402026209
Gaia DR2
Gaia DR2 6535499658122055552
Gaia DR3
Gaia DR3 6535499658122055552
System
WASP-4
Percentile among Gas Giant cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 1.34 Earth days (0.4% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0226 AU.
Transit Fingerprint
Depth
2.312 %
Duration
2.166 h
Impact parameter b
0.184
Rp / R★
0.152050
Transit midpoint (BJD)
2,455,804.5157
Photometric dip
Transit produces a flux drop of 23,120 ppm lasting ≈ 2.17 h.
Extended Orbital Architecture
Planet / star radius ratio
0.152050
Semi-major axis / stellar radius
5.411
Impact parameter (b)
0.184
RV semi-amplitude (K)
234.600 m/s
Transit mid-time (BJD)
2,455,804.5157
Long. of periastron (ω)
247.00°
Sky-projected obliquity (λ)
-1.00°
Angular separation (arcsec)
0.08460
Eq. Temperature
1,653K
(1380 °C)
Insolation (S⊕)
1,188.62
Earth = 1.00
Earth Similarity (ESI)
0.074
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.
Transit timing variations
Gravitational interactions from neighbours have been detected.
Discovery Paper
Primary reference
Wilson et al. 2008Instrument
iKon-L CCD Camera
Publication
2008-03
Observation locale
Ground
Discovery cohort
Planets confirmed in 2007 at SuperWASP (3 shown).
Host System: WASP-4
Spectral Class
G-type yellow (Sun-like)
Effective Temperature
5,436 K — cooler than the Sun (5,778 K)
Estimated Age
7.00 Gyr — older than the Sun (4.6 Gyr)
Stellar Radius
0.912 R☉
Stellar Mass
0.899 M☉
Metallicity [Fe/H]
-0.05
Extended Stellar Properties
Surface gravity (log g)
4.472 dex
Stellar density
1.671 g/cm³
Systemic radial velocity
57.73 km/s
Rotational v·sin i
1.97 km/s
Rotation period
22.20 days
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 11 bands
Astrometric Data
Parallax
3.715 mas
Total Proper Motion
88.073 mas/yr
PM Right Ascension
9.87 mas/yr
PM Declination
-87.52 mas/yr
Galactic Cartesian (pc)
x = 0.738 · y = -0.083 · z = -0.670
Equatorial (J2000)
RA 353.56291° · Dec -42.06178°
Galactic ℓ, b
344.492° · -68.296°
Ecliptic λ, β
335.071° · -35.559°
HTM-20 index
2002174647
Observation Record
Photometric series
13
RV measurements
1
Transmission spectra
3
Emission spectra
7
Archive notes
3
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