Key parameters at a glance
- A radius of 13.00 Earth radii
- A mass of 1,232.49 Earth masses
- Surface gravity around 7.29 g
- An orbital period of 4,799.000 days
- Semi-major axis 5.6000 AU
- Distance from Earth 41.05 light-years
- Earth Similarity Index 0.415
- Travel time at Voyager 1 speed 723,888 years
4 siblings around 55 Cnc
55 Cnc d shares its host star with 4 other confirmed planets. Side-by-side measurements below.
| Planet | Type | Radius (R⊕) | Mass (M⊕) | Period (d) | Eq. T (K) | Year |
|---|---|---|---|---|---|---|
| 55 Cnc e | Super-Earth | 1.88 | 7.99 | 0.737 | 1,958 | 2004 |
| 55 Cnc b | Gas Giant | 13.90 | 263.98 | 14.652 | 700 | 1996 |
| 55 Cnc c | Neptune-like | 8.51 | 54.47 | 44.394 | — | 2004 |
| 55 Cnc f | Neptune-like | 7.59 | 44.81 | 260.580 | — | 2007 |
| 55 Cnc d this | Gas Giant | 13.00 | 1,232.49 | 4,799.000 | — | 2002 |
55 Cnc d 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 | 55 Cnc d | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 13.00 | 11.21 |
| Mass (M⊕) | 1.00 | 1,232.49 | 317.83 |
| Density (g/cm³) | 5.51 | 3.08 | 1.33 |
| Surface Gravity (g) | 1.00 | 7.29 | 2.53 |
| Insolation (S⊕) | 1.00 | — | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Best measured mass | 1,232.493 M⊕ | Direct mass measurement (not derived). |
| Minimum mass (M sin i) | 1,214.105 M⊕ | Lower bound from radial-velocity fitting. |
Star Catalogue Identifiers
HD
HD 75732
HIP
HIP 43587
TIC
TIC 332064670
Gaia DR2
Gaia DR2 704967037090946688
Gaia DR3
Gaia DR3 704967037090946688
System
55 Cnc
Percentile among Gas Giant cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts about 13.14 Earth years on a nearly circular orbit at a mean orbital distance of 5.6000 AU.
Extended Orbital Architecture
RV semi-amplitude (K)
45.630 m/s
Transit mid-time (BJD)
2,451,517.8000
Long. of periastron (ω)
-90.00°
Angular separation (arcsec)
445.00000
Eq. Temperature
—
Insolation (S⊕)
—
Earth = 1.00
Earth Similarity (ESI)
0.415
0 = alien, 1 = Earth-identical
Discovery Paper
Primary reference
Marcy et al. 2002Instrument
Hamilton Echelle Spectrograph
Publication
2002-12
Observation locale
Ground
Discovery cohort
Planets confirmed in 2002 at Lick Observatory (3 shown).
Host System: 55 Cnc
Spectral Class
G-type yellow (Sun-like)
Effective Temperature
5,198 K — cooler than the Sun (5,778 K)
Estimated Age
10.00 Gyr — older than the Sun (4.6 Gyr)
Stellar Radius
0.980 R☉
Stellar Mass
1.015 M☉
Metallicity [Fe/H]
0.39
Extended Stellar Properties
Surface gravity (log g)
4.300 dex
Stellar density
1.521 g/cm³
Systemic radial velocity
27.41 km/s
Rotational v·sin i
1.06 km/s
Rotation period
39.00 days
Activity index (log R'HK)
-5.040
Metallicity ratio
[M/H]
Multi-band Host Photometry — 11 bands
Astrometric Data
Parallax
79.427 mas
Total Proper Motion
539.133 mas/yr
PM Right Ascension
-485.87 mas/yr
PM Declination
-233.65 mas/yr
Galactic Cartesian (pc)
x = -0.602 · y = 0.642 · z = 0.475
Equatorial (J2000)
RA 133.14684° · Dec 28.32982°
Galactic ℓ, b
196.795° · 37.697°
Ecliptic λ, β
127.727° · 10.366°
HTM-20 index
570333148
Observation Record
Photometric series
1
RV measurements
9
Stellar spectra
11
Archive notes
4
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