Key parameters at a glance
- A radius of 12.40 Earth radii
- A mass of 3,478.95 Earth masses
- Surface gravity around 22.63 g
- An orbital period of 2,269.817 days
- Semi-major axis 3.3950 AU
- Distance from Earth 173.78 light-years
- Earth Similarity Index 0.371
- Travel time at Voyager 1 speed 3,064,636 years
1 sibling around HD 66428
HD 66428 b shares its host star with 1 other confirmed planet. Side-by-side measurements below.
| Planet | Type | Radius (R⊕) | Mass (M⊕) | Period (d) | Eq. T (K) | Year |
|---|---|---|---|---|---|---|
| HD 66428 b this | Gas Giant | 12.40 | 3,478.95 | 2,269.817 | — | 2005 |
| HD 66428 c | Gas Giant | 13.50 | 560.65 | 10,478.844 | — | 2021 |
HD 66428 b Planet Profile
Physical Specs
Classification
Planet Type
Gas Giant
Discovery
Size rank in cohort
Rank by radius
#1298of 1771
top 73.2%
This planet
12.40R⊕
Gas Giant median
13.52R⊕
Nearest-size peers
| Metric | Earth | HD 66428 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 12.40 | 11.21 |
| Mass (M⊕) | 1.00 | 3,478.95 | 317.83 |
| Density (g/cm³) | 5.51 | 10.00 | 1.33 |
| Surface Gravity (g) | 1.00 | 22.63 | 2.53 |
| Insolation (S⊕) | 1.00 | — | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Best measured mass | 3,478.950 M⊕ | Direct mass measurement (not derived). |
| Minimum mass (M sin i) | 1,018.327 M⊕ | Lower bound from radial-velocity fitting. |
Star Catalogue Identifiers
HD
HD 66428
HIP
HIP 39417
TIC
TIC 73238215
Gaia DR2
Gaia DR2 3083043390405346432
Gaia DR3
Gaia DR3 3083043390405346432
System
HD 66428
Percentile among Gas Giant cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts about 6.21 Earth years on a highly eccentric trajectory at a mean orbital distance of 3.3950 AU.
Extended Orbital Architecture
RV semi-amplitude (K)
54.441 m/s
Transit mid-time (BJD)
2,456,562.0000
Long. of periastron (ω)
185.69°
Angular separation (arcsec)
63.70000
Eq. Temperature
—
Insolation (S⊕)
—
Earth = 1.00
Earth Similarity (ESI)
0.371
0 = alien, 1 = Earth-identical
Detection Signatures
Radial velocity
Stellar wobble has been measured spectroscopically.
Astrometry
Positional wobble of the host star was measured.
Discovery Paper
Primary reference
Butler et al. 2006Instrument
HIRES Spectrometer
Publication
2006-07
Observation locale
Ground
Discovery cohort
Planets confirmed in 2005 at W. M. Keck Observatory (12 shown).
Host System: HD 66428
Spectral Class
G-type yellow (Sun-like)
Effective Temperature
5,716 K — cooler than the Sun (5,778 K)
Estimated Age
3.52 Gyr — younger than the Sun (4.6 Gyr)
Stellar Radius
1.130 R☉
Stellar Mass
1.010 M☉
Metallicity [Fe/H]
0.23
Extended Stellar Properties
Surface gravity (log g)
4.330 dex
Stellar density
0.918 g/cm³
Systemic radial velocity
43.99 km/s
Rotational v·sin i
0.00 km/s
Rotation period
38.00 days
Activity index (log R'HK)
-5.080
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 11 bands
Astrometric Data
Parallax
18.740 mas
Total Proper Motion
217.124 mas/yr
PM Right Ascension
-65.73 mas/yr
PM Declination
-206.94 mas/yr
Galactic Cartesian (pc)
x = -0.513 · y = 0.858 · z = -0.020
Equatorial (J2000)
RA 120.86917° · Dec -1.16360°
Galactic ℓ, b
222.427° · 15.417°
Ecliptic λ, β
123.352° · -21.100°
HTM-20 index
-348764689
Observation Record
Photometric series
1
RV measurements
1
Stellar spectra
3
Archive notes
1
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