Key parameters at a glance
- A radius of 13.56 Earth radii
- A mass of 529.31 Earth masses
- Surface gravity around 2.88 g
- An orbital period of 1.360 days
- Semi-major axis 0.0232 AU
- Equilibrium temperature 1,674 K (1401 °C)
- Distance from Earth 343.01 light-years
- Earth Similarity Index 0.085
- Travel time at Voyager 1 speed 6,048,897 years
WASP-77 A b Planet Profile
Physical Specs
Classification
Planet Type
Gas Giant
Discovery
Size rank in cohort
Rank by radius
#666of 1771
top 37.5%
This planet
13.56R⊕
Gas Giant median
13.52R⊕
Nearest-size peers
| Metric | Earth | WASP-77 A b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 13.56 | 11.21 |
| Mass (M⊕) | 1.00 | 529.31 | 317.83 |
| Density (g/cm³) | 5.51 | 1.33 | 1.33 |
| Surface Gravity (g) | 1.00 | 2.88 | 2.53 |
| Insolation (S⊕) | 1.00 | 1,440.00 | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Best measured mass | 529.311 M⊕ | Direct mass measurement (not derived). |
| Minimum mass (M sin i) | 529.820 M⊕ | Lower bound from radial-velocity fitting. |
Star Catalogue Identifiers
TIC
TIC 1129033
Gaia DR2
Gaia DR2 5178405479960844160
Gaia DR3
Gaia DR3 5178405479961698048
System
WASP-77
Percentile among Gas Giant cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 1.36 Earth days (0.4% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0232 AU.
Transit Fingerprint
Depth
1.943 %
Duration
2.165 h
Impact parameter b
0.060
Rp / R★
0.117026
Transit midpoint (BJD)
2,459,957.3379
Photometric dip
Transit produces a flux drop of 19,428 ppm lasting ≈ 2.17 h.
Extended Orbital Architecture
Planet / star radius ratio
0.117026
Semi-major axis / stellar radius
5.490
Impact parameter (b)
0.060
RV semi-amplitude (K)
327.210 m/s
Transit mid-time (BJD)
2,459,957.3379
Long. of periastron (ω)
-88.29°
Angular separation (arcsec)
0.22100
Eq. Temperature
1,674K
(1401 °C)
Insolation (S⊕)
1,440.00
Earth = 1.00
Earth Similarity (ESI)
0.085
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
Maxted et al. 2013Instrument
iKon-L CCD Camera
Publication
2013-01
Observation locale
Ground
Discovery cohort
Planets confirmed in 2012 at SuperWASP (12 shown).
Host System: WASP-77 A
Spectral Class
G-type yellow (Sun-like)
Effective Temperature
5,617 K — cooler than the Sun (5,778 K)
Estimated Age
6.20 Gyr — older than the Sun (4.6 Gyr)
Stellar Radius
0.910 R☉
Stellar Mass
0.903 M☉
Metallicity [Fe/H]
-0.10
Extended Stellar Properties
Surface gravity (log g)
4.476 dex
Stellar density
1.692 g/cm³
Systemic radial velocity
1.68 km/s
Rotational v·sin i
4.00 km/s
Rotation period
15.40 days
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 16 bands
Astrometric Data
Parallax
9.482 mas
Total Proper Motion
93.902 mas/yr
PM Right Ascension
93.89 mas/yr
PM Declination
-1.57 mas/yr
Galactic Cartesian (pc)
x = 0.791 · y = 0.599 · z = -0.123
Equatorial (J2000)
RA 37.15552° · Dec -7.06067°
Galactic ℓ, b
176.350° · -59.436°
Ecliptic λ, β
32.349° · -20.561°
HTM-20 index
-971959002
Observation Record
RV measurements
2
Emission spectra
10
Archive notes
2
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