Key parameters at a glance

A radius of 2.50 Earth radii
A mass of 6.80 Earth masses
Surface gravity around 1.09 g
An orbital period of 25.631 days
Semi-major axis 0.1254 AU
Distance from Earth 49.34 light-years
Earth Similarity Index 0.704
Travel time at Voyager 1 speed 870,155 years
Almost certainly tidally locked to its host star given the close orbit

2 siblings around GJ 163

GJ 163 c shares its host star with 2 other confirmed planets. Side-by-side measurements below.

Planet	Type	Radius (R⊕)	Mass (M⊕)	Period (d)	Eq. T (K)	Year
GJ 163 b	Sub-Neptune	3.25	10.60	8.632	—	2013
GJ 163 c this	Sub-Neptune	2.50	6.80	25.631	—	2013
GJ 163 d	Neptune-like	5.92	29.40	603.951	—	2013

GJ 163 c Planet Profile

Physical Specs

Radius

2.50 R⊕

Radius (Jupiter)

0.223 R♃

Mass

6.80 M⊕

Mass (Jupiter)

0.021 M♃

Density

2.39 g/cm³

Surface Gravity

1.09 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.704

HZ Position Unknown

Controversial No

Discovery

Year 2013

Method Radial Velocity

Facility La Silla Observatory

Telescope 3.6 m ESO Telescope

Size rank in cohort

Rank by radius

#1168of 1978

top 59.0%

This planet

2.50R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

Kepler-254 d 2.50 R⊕ Kepler-298 d 2.50 R⊕ Kepler-126 d 2.50 R⊕

Metric	Earth	GJ 163 c	Jupiter
Radius (R⊕)	1.00	2.50	11.21
Mass (M⊕)	1.00	6.80	317.83
Density (g/cm³)	5.51	2.39	1.33
Surface Gravity (g)	1.00	1.09	2.53
Insolation (S⊕)	1.00	—	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Minimum mass (M sin i)	6.800 M⊕	Lower bound from radial-velocity fitting.

Star Catalogue Identifiers

HIP

HIP 19394

TIC

TIC 219221189

Gaia DR2

Gaia DR2 4780294722094459904

Gaia DR3

Gaia DR3 4780294722094459904

System

GJ 163

Percentile among Sub-Neptune cohort

Radius 2.500 R⊕ · percentile 40 / cohort 1978

Mass 6.800 M⊕ · percentile 37 / cohort 1978

Orbital period 25.63 d · percentile 70 / cohort 1946

Distance 15.13 pc · percentile 3 / cohort 1975

ESI 0.704 · percentile 93 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period

25.631 days

Semi-major axis

0.1254 AU

Eccentricity

0.099

Inclination

— °

Year Length

A year here lasts approximately 25.63 Earth days (7.0% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.1254 AU.

Eq. Temperature

—

Insolation (S⊕)

—

Earth = 1.00

Earth Similarity (ESI)

0.704

0 = alien, 1 = Earth-identical

Insufficient insolation data. Close-orbiting tidally-locked around a cool host.

Discovery Paper

Primary reference

Bonfils et al. 2013

Instrument

HARPS Spectrograph

Publication

2013-08

Observation locale

Ground

Discovery cohort

Planets confirmed in 2013 at La Silla Observatory (10 shown).

GJ 667 C c · Super-Earth HD 40307 f · Sub-Neptune GJ 163 b · Sub-Neptune HD 109271 b · Neptune-like HD 109271 c · Neptune-like POTS-1 b · Gas Giant GJ 163 d · Neptune-like HD 65216 c · Gas Giant BD-06 1339 c · Neptune-like HD 103774 b · Gas Giant

Host System: GJ 163

Spectral Class

M-type red dwarf

Effective Temperature

3,500 K — cooler than the Sun (5,778 K)

Estimated Age

6.00 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

0.410 R☉

Stellar Mass

0.400 M☉

Metallicity [Fe/H]

0.10

Extended Stellar Properties

Surface gravity (log g)

4.818 dex

Stellar density

8.248 g/cm³

Systemic radial velocity

58.60 km/s

Metallicity ratio

[Fe/H]

Distance

15.13 parsec

Light-years 49.34 ly

V-band magnitude

11.79 mag

Voyager-speed travel 870,155 yr

Multi-band Host Photometry — 12 bands

Astrometric Data

Parallax

66.071 mas

Total Proper Motion

1,198.172 mas/yr

PM Right Ascension

1,046.14 mas/yr

PM Declination

584.13 mas/yr

Galactic Cartesian (pc)

x = 0.277 · y = 0.528 · z = -0.803

Equatorial (J2000)

RA 62.32284° · Dec -53.37118°

Galactic ℓ, b

262.777° · -45.320°

Ecliptic λ, β

30.848° · -71.167°

HTM-20 index

-1724147858