Key parameters at a glance
- A radius of 8.97 Earth radii
- A mass of 37.19 Earth masses
- Surface gravity around 0.46 g
- An orbital period of 5.924 days
- Semi-major axis 0.0620 AU
- Equilibrium temperature 910 K (637 °C)
- Distance from Earth 692.99 light-years
- Earth Similarity Index 0.146
- Travel time at Voyager 1 speed 12,220,881 years
- Almost certainly tidally locked to its host star given the close orbit
WASP-139 b Planet Profile
Physical Specs
Classification
Planet Type
Neptune-like
Discovery
Size rank in cohort
Rank by radius
#93of 574
top 16.0%
This planet
8.97R⊕
Neptune-like median
6.39R⊕
Nearest-size peers
| Metric | Earth | WASP-139 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 8.97 | 11.21 |
| Mass (M⊕) | 1.00 | 37.19 | 317.83 |
| Density (g/cm³) | 5.51 | 0.31 | 1.33 |
| Surface Gravity (g) | 1.00 | 0.46 | 2.53 |
| Insolation (S⊕) | 1.00 | 120.71 | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Best measured mass | 37.186 M⊕ | Direct mass measurement (not derived). |
Star Catalogue Identifiers
TIC
TIC 159951311
Gaia DR2
Gaia DR2 4851398799032507776
Gaia DR3
Gaia DR3 4851398799032507776
System
WASP-139
Percentile among Neptune-like cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 5.92 Earth days (1.6% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0620 AU.
Transit Fingerprint
Depth
1.070 %
Duration
2.832 h
Impact parameter b
0.330
Rp / R★
0.103400
Transit midpoint (BJD)
2,457,196.7933
Photometric dip
Transit produces a flux drop of 10,700 ppm lasting ≈ 2.83 h.
Extended Orbital Architecture
Planet / star radius ratio
0.103400
Semi-major axis / stellar radius
17.190
Impact parameter (b)
0.330
RV semi-amplitude (K)
14.000 m/s
Transit mid-time (BJD)
2,457,196.7933
Angular separation (arcsec)
0.29200
Eq. Temperature
910K
(637 °C)
Insolation (S⊕)
120.71
Earth = 1.00
Earth Similarity (ESI)
0.146
0 = alien, 1 = Earth-identical
Inside the inner HZ boundary (too hot for liquid water) — the surface is too hot to retain surface water. 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
Hellier et al. 2017Instrument
iKon-L CCD Camera
Publication
2017-03
Observation locale
Ground
Discovery cohort
Planets confirmed in 2016 at SuperWASP-South (11 shown).
Host System: WASP-139
Spectral Class
K-type orange
Effective Temperature
5,310 K — cooler than the Sun (5,778 K)
Estimated Age
0.50 Gyr — younger than the Sun (4.6 Gyr)
Stellar Radius
0.800 R☉
Stellar Mass
0.920 M☉
Metallicity [Fe/H]
0.20
Extended Stellar Properties
Surface gravity (log g)
4.590 dex
Stellar density
2.500 g/cm³
Systemic radial velocity
-13.00 km/s
Rotational v·sin i
4.20 km/s
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 11 bands
Astrometric Data
Parallax
4.678 mas
Total Proper Motion
29.271 mas/yr
PM Right Ascension
-16.00 mas/yr
PM Declination
24.51 mas/yr
Galactic Cartesian (pc)
x = 0.487 · y = 0.572 · z = -0.660
Equatorial (J2000)
RA 49.56217° · Dec -41.30202°
Galactic ℓ, b
247.794° · -56.825°
Ecliptic λ, β
28.267° · -56.409°
HTM-20 index
1766916568
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