Key parameters at a glance
- A radius of 17.71 Earth radii
- A mass of 161.46 Earth masses
- Surface gravity around 0.51 g
- An orbital period of 3.072 days
- Semi-major axis 0.0396 AU
- Equilibrium temperature 1,142 K (869 °C)
- Distance from Earth 576.70 light-years
- Earth Similarity Index 0.085
- Travel time at Voyager 1 speed 10,170,148 years
- Almost certainly tidally locked to its host star given the close orbit
WASP-177 b Planet Profile
Physical Specs
Classification
Planet Type
Gas Giant
Discovery
Size rank in cohort
Rank by radius
#85of 1771
top 4.7%
This planet
17.71R⊕
Gas Giant median
13.52R⊕
Nearest-size peers
| Metric | Earth | WASP-177 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 17.71 | 11.21 |
| Mass (M⊕) | 1.00 | 161.46 | 317.83 |
| Density (g/cm³) | 5.51 | 0.17 | 1.33 |
| Surface Gravity (g) | 1.00 | 0.51 | 2.53 |
| Insolation (S⊕) | 1.00 | 279.77 | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Best measured mass | 161.458 M⊕ | Direct mass measurement (not derived). |
Star Catalogue Identifiers
TIC
TIC 439842788
Gaia DR2
Gaia DR2 2677447294810845824
Gaia DR3
Gaia DR3 2677447294810845824
System
WASP-177
Percentile among Gas Giant cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 3.07 Earth days (0.8% of a terrestrial year) at a mean orbital distance of 0.0396 AU.
Transit Fingerprint
Depth
1.850 %
Duration
1.613 h
Impact parameter b
0.980
Rp / R★
0.136000
Transit midpoint (BJD)
2,457,994.3714
Photometric dip
Transit produces a flux drop of 18,500 ppm lasting ≈ 1.61 h.
Extended Orbital Architecture
Planet / star radius ratio
0.136000
Semi-major axis / stellar radius
9.610
Impact parameter (b)
0.980
RV semi-amplitude (K)
77.300 m/s
Transit mid-time (BJD)
2,457,994.3714
Angular separation (arcsec)
0.22400
Eq. Temperature
1,142K
(869 °C)
Insolation (S⊕)
279.77
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. 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
Turner et al. 2019Instrument
iKon-L CCD Camera
Publication
2019-06
Observation locale
Ground
Discovery cohort
Planets confirmed in 2019 at SuperWASP (3 shown).
Host System: WASP-177
Spectral Class
K-type orange
Effective Temperature
5,017 K — cooler than the Sun (5,778 K)
Estimated Age
9.70 Gyr — older than the Sun (4.6 Gyr)
Stellar Radius
0.885 R☉
Stellar Mass
0.876 M☉
Metallicity [Fe/H]
0.25
Extended Stellar Properties
Surface gravity (log g)
4.486 dex
Stellar density
1.780 g/cm³
Systemic radial velocity
-7.14 km/s
Rotational v·sin i
1.80 km/s
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 16 bands
Astrometric Data
Parallax
5.628 mas
Total Proper Motion
80.377 mas/yr
PM Right Ascension
-57.59 mas/yr
PM Declination
-56.07 mas/yr
Galactic Cartesian (pc)
x = 0.904 · y = -0.426 · z = -0.032
Equatorial (J2000)
RA 334.79699° · Dec -1.83443°
Galactic ℓ, b
61.127° · -45.640°
Ecliptic λ, β
335.965° · 8.044°
HTM-20 index
-138613325
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