Key parameters at a glance
- A mass of 1,568.17 Earth masses
- An orbital period of 24.451 days
- Semi-major axis 0.1551 AU
- Equilibrium temperature 499 K (226 °C)
- Distance from Earth 55.42 light-years
- Travel time at Voyager 1 speed 977,351 years
- Almost certainly tidally locked to its host star given the close orbit
2 siblings around HD 7924
HD 7924 d shares its host star with 2 other confirmed planets. Side-by-side measurements below.
HD 7924 d Planet Profile
Physical Specs
Classification
Planet Type
Unclassified
Discovery
| Metric | Earth | HD 7924 d | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | — | 11.21 |
| Mass (M⊕) | 1.00 | 1,568.17 | 317.83 |
| Density (g/cm³) | 5.51 | — | 1.33 |
| Surface Gravity (g) | 1.00 | — | 2.53 |
| Insolation (S⊕) | 1.00 | 15.17 | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Best measured mass | 1,568.165 M⊕ | Direct mass measurement (not derived). |
| Minimum mass (M sin i) | 6.440 M⊕ | Lower bound from radial-velocity fitting. |
Star Catalogue Identifiers
HD
HD 7924
HIP
HIP 6379
TIC
TIC 468723402
Gaia DR2
Gaia DR2 560130775546153344
Gaia DR3
Gaia DR3 560130775546153344
System
HD 7924
Percentile among Unclassified cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 24.45 Earth days (6.7% of a terrestrial year) on a mildly elliptical path at a mean orbital distance of 0.1551 AU.
Extended Orbital Architecture
RV semi-amplitude (K)
1.650 m/s
Transit mid-time (BJD)
2,455,188.3000
Long. of periastron (ω)
119.00°
Angular separation (arcsec)
9.13000
Eq. Temperature
499K
(226 °C)
Insolation (S⊕)
15.17
Earth = 1.00
Earth Similarity (ESI)
—
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.
Discovery Paper
Primary reference
Fulton et al. 2015Instrument
HIRES Spectrometer
Publication
2015-06
Observation locale
Ground
Discovery cohort
Planets confirmed in 2015 at W. M. Keck Observatory (3 shown).
Host System: HD 7924
Spectral Class
K-type orange
Effective Temperature
5,075 K — cooler than the Sun (5,778 K)
Estimated Age
0.88 Gyr — younger than the Sun (4.6 Gyr)
Stellar Radius
0.782 R☉
Stellar Mass
0.832 M☉
Metallicity [Fe/H]
-0.15
Extended Stellar Properties
Surface gravity (log g)
4.590 dex
Stellar density
2.478 g/cm³
Systemic radial velocity
-22.70 km/s
Rotational v·sin i
1.35 km/s
Activity index (log R'HK)
-4.830
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 11 bands
Astrometric Data
Parallax
58.822 mas
Total Proper Motion
47.611 mas/yr
PM Right Ascension
-34.64 mas/yr
PM Declination
-32.66 mas/yr
Galactic Cartesian (pc)
x = 0.215 · y = 0.080 · z = 0.973
Equatorial (J2000)
RA 20.49566° · Dec 76.71015°
Galactic ℓ, b
124.736° · 13.945°
Ecliptic λ, β
64.958° · 59.417°
HTM-20 index
-1953656461
Observation Record
Photometric series
1
RV measurements
1
Stellar spectra
8
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HD 215152 c
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HD 40307 c
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