Key parameters at a glance
- A radius of 13.00 Earth radii
- A mass of 112.20 Earth masses
- Surface gravity around 0.66 g
- An orbital period of 101.120 days
- Semi-major axis 0.4070 AU
- Equilibrium temperature 390 K (117 °C)
- Distance from Earth 174.85 light-years
- Earth Similarity Index 0.287
- Travel time at Voyager 1 speed 3,083,456 years
5 siblings around HD 191939
HD 191939 e shares its host star with 5 other confirmed planets. Side-by-side measurements below.
| Planet | Type | Radius (R⊕) | Mass (M⊕) | Period (d) | Eq. T (K) | Year |
|---|---|---|---|---|---|---|
| HD 191939 b | Sub-Neptune | 3.41 | 10.00 | 8.880 | 880 | 2020 |
| HD 191939 c | Sub-Neptune | 3.20 | 8.00 | 28.580 | 600 | 2020 |
| HD 191939 d | Sub-Neptune | 3.00 | 2.80 | 38.353 | 540 | 2020 |
| HD 191939 e this | Gas Giant | 13.00 | 112.20 | 101.120 | 390 | 2022 |
| HD 191939 g | Sub-Neptune | 3.74 | 13.50 | 284.000 | 278 | 2022 |
| HD 191939 f | Gas Giant | 13.20 | 915.35 | 2,898.000 | 125 | 2022 |
HD 191939 e Planet Profile
Physical Specs
Classification
Planet Type
Gas Giant
Discovery
Size rank in cohort
Rank by radius
#960of 1771
top 54.2%
This planet
13.00R⊕
Gas Giant median
13.52R⊕
Nearest-size peers
| Metric | Earth | HD 191939 e | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 13.00 | 11.21 |
| Mass (M⊕) | 1.00 | 112.20 | 317.83 |
| Density (g/cm³) | 5.51 | 0.28 | 1.33 |
| Surface Gravity (g) | 1.00 | 0.66 | 2.53 |
| Insolation (S⊕) | 1.00 | 3.90 | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Minimum mass (M sin i) | 112.200 M⊕ | Lower bound from radial-velocity fitting. |
Star Catalogue Identifiers
HD
HD 191939
HIP
HIP 99175
TIC
TIC 269701147
Gaia DR2
Gaia DR2 2248126315275354496
Gaia DR3
Gaia DR3 2248126315275354496
System
HD 191939
Percentile among Gas Giant cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 101.12 Earth days (27.7% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.4070 AU.
Extended Orbital Architecture
Semi-major axis / stellar radius
92.900
RV semi-amplitude (K)
17.730 m/s
Transit mid-time (BJD)
2,459,348.1200
Long. of periastron (ω)
-130.00°
Angular separation (arcsec)
7.59000
Eq. Temperature
390K
(117 °C)
Insolation (S⊕)
3.90
Earth = 1.00
Earth Similarity (ESI)
0.287
0 = alien, 1 = Earth-identical
Inside the inner HZ boundary (too hot for liquid water) — the surface is too hot to retain surface water.
Discovery Paper
Primary reference
Lubin et al. 2022Instrument
HIRES Spectrometer
Publication
2022-02
Observation locale
Ground
Discovery cohort
Planets confirmed in 2022 at W. M. Keck Observatory (3 shown).
Host System: HD 191939
Spectral Class
G-type yellow (Sun-like)
Effective Temperature
5,348 K — cooler than the Sun (5,778 K)
Estimated Age
8.70 Gyr — older than the Sun (4.6 Gyr)
Stellar Radius
0.940 R☉
Stellar Mass
0.810 M☉
Metallicity [Fe/H]
-0.15
Extended Stellar Properties
Surface gravity (log g)
4.300 dex
Stellar density
1.370 g/cm³
Systemic radial velocity
-9.50 km/s
Rotational v·sin i
2.00 km/s
Activity index (log R'HK)
-5.110
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 11 bands
Astrometric Data
Parallax
18.625 mas
Total Proper Motion
163.283 mas/yr
PM Right Ascension
150.26 mas/yr
PM Declination
-63.91 mas/yr
Galactic Cartesian (pc)
x = 0.208 · y = -0.333 · z = 0.919
Equatorial (J2000)
RA 302.02562° · Dec 66.85030°
Galactic ℓ, b
99.987° · 17.722°
Ecliptic λ, β
16.039° · 77.471°
HTM-20 index
-1738980752
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