Key parameters at a glance

A radius of 12.80 Earth radii
A mass of 1,662.56 Earth masses
Surface gravity around 10.15 g
An orbital period of 966.490 days
Semi-major axis 2.3180 AU
Distance from Earth 154.60 light-years
Earth Similarity Index 0.433
Travel time at Voyager 1 speed 2,726,432 years

1 sibling around gam Lib

gam Lib 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
gam Lib b	Gas Giant	13.70	357.87	414.880	—	2018
gam Lib c this	Gas Giant	12.80	1,662.56	966.490	—	2018

gam Lib c Planet Profile

Physical Specs

Radius

12.80 R⊕

Radius (Jupiter)

1.140 R♃

Mass

1,662.56 M⊕

Mass (Jupiter)

5.231 M♃

Density

4.36 g/cm³

Surface Gravity

10.15 g (Earth)

Classification

Planet Type

Gas Giant

ESI Score 0.433

HZ Position Unknown

Controversial No

Discovery

Year 2018

Method Radial Velocity

Facility Okayama Astrophysical Observatory

Telescope 1.88 m Telescope

Size rank in cohort

Rank by radius

#1063of 1771

top 60.0%

This planet

12.80R⊕

Gas Giant median

13.52R⊕

Nearest-size peers

HD 240210 b 12.80 R⊕ HD 29985 b 12.80 R⊕ HD 148164 c 12.80 R⊕

Metric	Earth	gam Lib c	Jupiter
Radius (R⊕)	1.00	12.80	11.21
Mass (M⊕)	1.00	1,662.56	317.83
Density (g/cm³)	5.51	4.36	1.33
Surface Gravity (g)	1.00	10.15	2.53
Insolation (S⊕)	1.00	—	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Minimum mass (M sin i)	1,662.560 M⊕	Lower bound from radial-velocity fitting.

Star Catalogue Identifiers

HD 138905

HIP

HIP 76333

TIC

TIC 386935627

Gaia DR2

Gaia DR2 6265374394490149248

Gaia DR3

Gaia DR3 6265374394490973184

System

gam Lib

Percentile among Gas Giant cohort

Radius 12.800 R⊕ · percentile 37 / cohort 1771

Mass 1,662.560 M⊕ · percentile 76 / cohort 1747

Orbital period 966.49 d · percentile 76 / cohort 1533

Distance 47.40 pc · percentile 18 / cohort 1759

ESI 0.433 · percentile 95 / cohort 1771

Orbit & Habitability

Orbital Dynamics

Period

966.490 days

Semi-major axis

2.3180 AU

Eccentricity

0.065

Inclination

— °

Year Length

A year here lasts about 2.65 Earth years on a nearly circular orbit at a mean orbital distance of 2.3180 AU.

Eq. Temperature

—

Insolation (S⊕)

—

Earth = 1.00

Earth Similarity (ESI)

0.433

0 = alien, 1 = Earth-identical

Discovery Paper

Primary reference

Takarada et al. 2018

Instrument

HIDES Echelle Spectrograph

Publication

2018-08

Observation locale

Ground

Discovery cohort

Planets confirmed in 2018 at Okayama Astrophysical Observatory (2 shown).

gam Lib b · Gas Giant 24 Boo b · Gas Giant

Host System: gam Lib

Spectral Class

K-type orange

Effective Temperature

4,879 K — cooler than the Sun (5,778 K)

Estimated Age

2.82 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

12.380 R☉

Stellar Mass

1.780 M☉

Metallicity [Fe/H]

-0.27

Extended Stellar Properties

Surface gravity (log g)

2.500 dex

Rotational v·sin i

1.55 km/s

Metallicity ratio

[Fe/H]

Distance

47.40 parsec

Light-years 154.60 ly

V-band magnitude

3.91 mag

Voyager-speed travel 2,726,432 yr

Multi-band Host Photometry — 12 bands

Astrometric Data

Parallax

21.082 mas

Total Proper Motion

64.585 mas/yr

PM Right Ascension

63.82 mas/yr

PM Declination

9.89 mas/yr

Galactic Cartesian (pc)

x = -0.570 · y = -0.781 · z = -0.255

Equatorial (J2000)

RA 233.88186° · Dec -14.78950°

Galactic ℓ, b

351.515° · 32.196°

Ecliptic λ, β

235.134° · 4.386°

HTM-20 index

871432000

Similar Worlds

HD 99706 c

Gas Giant · K-type orange

Radius 12.80 R⊕ · 478.1 ly

HD 135872 b

Gas Giant · K-type orange

Radius 12.80 R⊕ · 268.8 ly

WASP-132 d

Gas Giant · K-type orange

Radius 12.80 R⊕ · 400.9 ly

HD 240210 b

Gas Giant · K-type orange

Radius 12.80 R⊕ · 1,214.6 ly

WISPIT 1 c

Gas Giant · K-type orange

Radius 12.80 R⊕ · 750.2 ly

Kepler-56 d

Gas Giant · K-type orange

Radius 12.80 R⊕ · 2,977.8 ly

Explore Related Categories

Gas Giant Planets Radial Velocity Discoveries Okayama Astrophysical Observatory Mission K-type orange Hosts