Key parameters at a glance
- A radius of 4.12 Earth radii
- A mass of 15.90 Earth masses
- Surface gravity around 0.94 g
- An orbital period of 5.736 days
- Semi-major axis 0.0600 AU
- Distance from Earth 149.82 light-years
- Earth Similarity Index 0.535
- Travel time at Voyager 1 speed 2,642,071 years
- Almost certainly tidally locked to its host star given the close orbit
Context from the literature
HD 77338 is a star with a close orbiting exoplanet companion in the southern constellation of Pyxis. It is too dim to be visible with the naked eye, having an apparent visual magnitude of 8.63. The system is located at a distance of 149 light years, and it is drifting further away with a heliocentric radial velocity of 8.2 km/s.
Excerpted from Wikipedia · full article
HD 77338 b Planet Profile
Physical Specs
Classification
Planet Type
Neptune-like
Discovery
Size rank in cohort
Rank by radius
#542of 574
top 94.3%
This planet
4.12R⊕
Neptune-like median
6.39R⊕
Nearest-size peers
| Metric | Earth | HD 77338 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 4.12 | 11.21 |
| Mass (M⊕) | 1.00 | 15.90 | 317.83 |
| Density (g/cm³) | 5.51 | 1.25 | 1.33 |
| Surface Gravity (g) | 1.00 | 0.94 | 2.53 |
| Insolation (S⊕) | 1.00 | — | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Best measured mass | 15.900 M⊕ | Direct mass measurement (not derived). |
| Minimum mass (M sin i) | 19.070 M⊕ | Lower bound from radial-velocity fitting. |
Star Catalogue Identifiers
HD
HD 77338
HIP
HIP 44291
TIC
TIC 37533318
Gaia DR2
Gaia DR2 5649661592466640000
Gaia DR3
Gaia DR3 5649661592466640000
System
HD 77338
Percentile among Neptune-like cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 5.74 Earth days (1.6% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0600 AU.
Eq. Temperature
—
Insolation (S⊕)
—
Earth = 1.00
Earth Similarity (ESI)
0.535
0 = alien, 1 = Earth-identical
Insufficient insolation data. Close-orbiting tidally-locked around a cool host.
Discovery Paper
Primary reference
Jenkins et al. 2013Instrument
HARPS Spectrograph
Publication
2013-04
Observation locale
Ground
Discovery cohort
Planets confirmed in 2012 at La Silla Observatory (11 shown).
Host System: HD 77338
Spectral Class
K-type orange
Effective Temperature
5,341 K — cooler than the Sun (5,778 K)
Estimated Age
—
Stellar Radius
0.970 R☉
Stellar Mass
1.370 M☉
Metallicity [Fe/H]
0.32
Extended Stellar Properties
Surface gravity (log g)
4.600 dex
Stellar density
1.461 g/cm³
Systemic radial velocity
8.21 km/s
Rotational v·sin i
2.33 km/s
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 11 bands
Astrometric Data
Parallax
21.741 mas
Total Proper Motion
274.527 mas/yr
PM Right Ascension
39.87 mas/yr
PM Declination
-271.62 mas/yr
Galactic Cartesian (pc)
x = -0.641 · y = 0.635 · z = -0.431
Equatorial (J2000)
RA 135.30225° · Dec -25.52823°
Galactic ℓ, b
251.364° · 13.552°
Ecliptic λ, β
147.353° · -40.381°
HTM-20 index
7507450
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