Key parameters at a glance
- A radius of 13.45 Earth radii
- A mass of 1,172.79 Earth masses
- Surface gravity around 6.48 g
- An orbital period of 1.387 days
- Semi-major axis 0.0248 AU
- Equilibrium temperature 1,880 K (1607 °C)
- Distance from Earth 759.88 light-years
- Earth Similarity Index 0.080
- Travel time at Voyager 1 speed 13,400,452 years
WASP-173 A b Planet Profile
Physical Specs
Classification
Planet Type
Gas Giant
Discovery
Size rank in cohort
Rank by radius
#723of 1771
top 40.8%
This planet
13.45R⊕
Gas Giant median
13.52R⊕
Nearest-size peers
| Metric | Earth | WASP-173 A b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 13.45 | 11.21 |
| Mass (M⊕) | 1.00 | 1,172.79 | 317.83 |
| Density (g/cm³) | 5.51 | 2.84 | 1.33 |
| Surface Gravity (g) | 1.00 | 6.48 | 2.53 |
| Insolation (S⊕) | 1.00 | 1,920.00 | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Best measured mass | 1,172.793 M⊕ | Direct mass measurement (not derived). |
| Minimum mass (M sin i) | 1,099.692 M⊕ | Lower bound from radial-velocity fitting. |
| Computed mass | 1,101.747 M⊕ | Model-computed mass (e.g. from mass-radius relation). |
Star Catalogue Identifiers
TIC
TIC 77031414
Gaia DR2
Gaia DR2 2323985539482908416
Gaia DR3
Gaia DR3 2323985539482908416
System
WASP-173
Percentile among Gas Giant cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 1.39 Earth days (0.4% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0248 AU.
Transit Fingerprint
Depth
1.230 %
Duration
2.297 h
Impact parameter b
0.400
Rp / R★
0.110900
Transit midpoint (BJD)
2,457,288.8585
Photometric dip
Transit produces a flux drop of 12,300 ppm lasting ≈ 2.30 h.
Extended Orbital Architecture
Planet / star radius ratio
0.110900
Semi-major axis / stellar radius
4.780
Impact parameter (b)
0.400
RV semi-amplitude (K)
645.000 m/s
Transit mid-time (BJD)
2,457,288.8585
Sky-projected obliquity (λ)
11.00°
True obliquity (ψ)
30.00°
Angular separation (arcsec)
0.10600
Eq. Temperature
1,880K
(1607 °C)
Insolation (S⊕)
1,920.00
Earth = 1.00
Earth Similarity (ESI)
0.080
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
Hellier et al. 2019Instrument
iKon-L CCD Camera
Publication
2019-01
Observation locale
Ground
Discovery cohort
Planets confirmed in 2018 at SuperWASP-South (12 shown).
Host System: WASP-173 A
Spectral Class
G-type yellow (Sun-like)
Effective Temperature
5,800 K — hotter than the Sun (5,778 K)
Estimated Age
6.78 Gyr — older than the Sun (4.6 Gyr)
Stellar Radius
1.110 R☉
Stellar Mass
1.050 M☉
Metallicity [Fe/H]
0.16
Extended Stellar Properties
Surface gravity (log g)
4.370 dex
Stellar density
1.100 g/cm³
Systemic radial velocity
-7.86 km/s
Rotational v·sin i
6.10 km/s
Rotation period
8.40 days
Multi-band Host Photometry — 14 bands
Astrometric Data
Parallax
4.264 mas
Total Proper Motion
88.379 mas/yr
PM Right Ascension
87.96 mas/yr
PM Declination
-8.56 mas/yr
Galactic Cartesian (pc)
x = 0.819 · y = -0.084 · z = -0.568
Equatorial (J2000)
RA 354.16870° · Dec -34.61130°
Galactic ℓ, b
3.300° · -72.336°
Ecliptic λ, β
339.709° · -29.201°
HTM-20 index
1214951962
Similar Worlds
WASP-155 b
Gas Giant · G-type yellow (Sun-like)
Radius 13.45 R⊕ · 1,303.4 ly
Kepler-418 b
Gas Giant · G-type yellow (Sun-like)
Radius 13.45 R⊕ · 3,269.8 ly
WASP-96 b
Gas Giant · G-type yellow (Sun-like)
Radius 13.45 R⊕ · 1,149.6 ly
WASP-163 b
Gas Giant · G-type yellow (Sun-like)
Radius 13.47 R⊕ · 852.5 ly
Kepler-87 b
Gas Giant · G-type yellow (Sun-like)
Radius 13.49 R⊕ · 4,021.2 ly
HD 233832 b
Gas Giant · G-type yellow (Sun-like)
Radius 13.50 R⊕ · 191.6 ly