Key parameters at a glance
- A radius of 13.20 Earth radii
- A mass of 912.17 Earth masses
- Surface gravity around 5.24 g
- An orbital period of 3,810.000 days
- Semi-major axis 4.8900 AU
- Distance from Earth 149.88 light-years
- Earth Similarity Index 0.393
- Travel time at Voyager 1 speed 2,643,210 years
1 sibling around HD 187123
HD 187123 c 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 187123 b | Gas Giant | 14.20 | 166.22 | 3.097 | — | 1998 |
| HD 187123 c this | Gas Giant | 13.20 | 912.17 | 3,810.000 | — | 2008 |
HD 187123 c Planet Profile
Physical Specs
Classification
Planet Type
Gas Giant
Discovery
Size rank in cohort
Rank by radius
#847of 1771
top 47.8%
This planet
13.20R⊕
Gas Giant median
13.52R⊕
Nearest-size peers
| Metric | Earth | HD 187123 c | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 13.20 | 11.21 |
| Mass (M⊕) | 1.00 | 912.17 | 317.83 |
| Density (g/cm³) | 5.51 | 2.18 | 1.33 |
| Surface Gravity (g) | 1.00 | 5.24 | 2.53 |
| Insolation (S⊕) | 1.00 | — | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Best measured mass | 912.168 M⊕ | Direct mass measurement (not derived). |
| Minimum mass (M sin i) | 632.460 M⊕ | Lower bound from radial-velocity fitting. |
Star Catalogue Identifiers
HD
HD 187123
HIP
HIP 97336
TIC
TIC 58559140
Gaia DR2
Gaia DR2 2047452661412980736
Gaia DR3
Gaia DR3 2047452661412980736
System
HD 187123
Percentile among Gas Giant cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts about 10.43 Earth years on a mildly elliptical path at a mean orbital distance of 4.8900 AU.
Extended Orbital Architecture
RV semi-amplitude (K)
25.500 m/s
Transit mid-time (BJD)
2,458,871.0000
Long. of periastron (ω)
243.00°
Angular separation (arcsec)
106.00000
Eq. Temperature
—
Insolation (S⊕)
—
Earth = 1.00
Earth Similarity (ESI)
0.393
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
Wright et al. 2009Instrument
HIRES Spectrometer
Publication
2009-03
Observation locale
Ground
Discovery cohort
Planets confirmed in 2008 at W. M. Keck Observatory (7 shown).
Host System: HD 187123
Spectral Class
G-type yellow (Sun-like)
Effective Temperature
5,790 K — hotter than the Sun (5,778 K)
Estimated Age
7.40 Gyr — older than the Sun (4.6 Gyr)
Stellar Radius
1.150 R☉
Stellar Mass
1.040 M☉
Metallicity [Fe/H]
0.09
Extended Stellar Properties
Surface gravity (log g)
4.333 dex
Stellar density
0.963 g/cm³
Systemic radial velocity
-16.99 km/s
Rotational v·sin i
2.10 km/s
Activity index (log R'HK)
-5.030
Metallicity ratio
[M/H]
Multi-band Host Photometry — 11 bands
Astrometric Data
Parallax
21.732 mas
Total Proper Motion
188.698 mas/yr
PM Right Ascension
142.58 mas/yr
PM Declination
-123.60 mas/yr
Galactic Cartesian (pc)
x = 0.371 · y = -0.737 · z = 0.565
Equatorial (J2000)
RA 296.74288° · Dec 34.41899°
Galactic ℓ, b
69.466° · 4.679°
Ecliptic λ, β
309.449° · 54.256°
HTM-20 index
-767094899
Observation Record
Photometric series
1
RV measurements
4
Stellar spectra
2
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