Key parameters at a glance
- A radius of 14.30 Earth radii
- A mass of 133.49 Earth masses
- Surface gravity around 0.65 g
- An orbital period of 3.444 days
- Semi-major axis 0.0400 AU
- Distance from Earth 179.26 light-years
- Earth Similarity Index 0.241
- Travel time at Voyager 1 speed 3,161,288 years
- Almost certainly tidally locked to its host star given the close orbit
HD 2638 b Planet Profile
Physical Specs
Classification
Planet Type
Gas Giant
Discovery
Size rank in cohort
Rank by radius
#301of 1771
top 16.9%
This planet
14.30R⊕
Gas Giant median
13.52R⊕
Nearest-size peers
| Metric | Earth | HD 2638 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 14.30 | 11.21 |
| Mass (M⊕) | 1.00 | 133.49 | 317.83 |
| Density (g/cm³) | 5.51 | 0.25 | 1.33 |
| Surface Gravity (g) | 1.00 | 0.65 | 2.53 |
| Insolation (S⊕) | 1.00 | — | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Minimum mass (M sin i) | 133.489 M⊕ | Lower bound from radial-velocity fitting. |
Star Catalogue Identifiers
HD
HD 2638
HIP
HIP 2350
TIC
TIC 244178536
Gaia DR2
Gaia DR2 2526925389919277056
Gaia DR3
Gaia DR3 2526925389919277056
System
HD 2638
Percentile among Gas Giant cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 3.44 Earth days (0.9% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0400 AU.
Eq. Temperature
—
Insolation (S⊕)
—
Earth = 1.00
Earth Similarity (ESI)
0.241
0 = alien, 1 = Earth-identical
Insufficient insolation data. Close-orbiting tidally-locked around a cool host.
Discovery Paper
Primary reference
Moutou et al. 2005Instrument
HARPS Spectrograph
Publication
2005-08
Observation locale
Ground
Discovery cohort
Planets confirmed in 2005 at La Silla Observatory (10 shown).
Host System: HD 2638
Spectral Class
K-type orange
Effective Temperature
5,186 K — cooler than the Sun (5,778 K)
Estimated Age
3.00 Gyr — younger than the Sun (4.6 Gyr)
Stellar Radius
0.940 R☉
Stellar Mass
0.770 M☉
Metallicity [Fe/H]
0.13
Extended Stellar Properties
Surface gravity (log g)
4.380 dex
Stellar density
1.835 g/cm³
Systemic radial velocity
9.63 km/s
Rotational v·sin i
1.10 km/s
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 11 bands
Astrometric Data
Parallax
18.166 mas
Total Proper Motion
247.385 mas/yr
PM Right Ascension
-107.02 mas/yr
PM Declination
-223.04 mas/yr
Galactic Cartesian (pc)
x = 0.986 · y = 0.130 · z = -0.100
Equatorial (J2000)
RA 7.49900° · Dec -5.76496°
Galactic ℓ, b
108.543° · -68.036°
Ecliptic λ, β
4.585° · -8.268°
HTM-20 index
641997843
Observation Record
Photometric series
1
RV measurements
1
Archive notes
2
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