Key parameters at a glance

A radius of 1.10 Earth radii
A mass of 1.36 Earth masses
Surface gravity around 1.12 g
An orbital period of 21.202 days
Semi-major axis 0.0738 AU
Equilibrium temperature 182 K (-91 °C)
Distance from Earth 15.81 light-years
Earth Similarity Index 0.686
Travel time at Voyager 1 speed 278,884 years
Almost certainly tidally locked to its host star given the close orbit

Context from the literature

GJ 1002, or LHS 2, is a nearby red dwarf star, located 15.8 light-years away from the Solar System in the constellation of Cetus. At an apparent magnitude of 13.8, it is much too faint to be visible to the naked eye. It hosts a system of two known exoplanets.

Excerpted from Wikipedia · full article

1 sibling around GJ 1002

GJ 1002 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
GJ 1002 b	Rocky Terrestrial	1.03	1.08	10.347	231	2022
GJ 1002 c this	Rocky Terrestrial	1.10	1.36	21.202	182	2022

GJ 1002 c Planet Profile

Physical Specs

Radius

1.10 R⊕

Radius (Jupiter)

0.098 R♃

Mass

1.36 M⊕

Mass (Jupiter)

0.004 M♃

Density

5.61 g/cm³

Surface Gravity

1.12 g (Earth)

Classification

Planet Type

Rocky Terrestrial

ESI Score 0.686

HZ Position Outer

Controversial No

Discovery

Year 2022

Method Radial Velocity

Facility Multiple Observatories

Telescope Multiple Telescopes

Size rank in cohort

Rank by radius

#224of 570

top 39.1%

This planet

1.10R⊕

Rocky Terrestrial median

1.01R⊕

Nearest-size peers

Kepler-392 c 1.10 R⊕ Kepler-59 b 1.10 R⊕ K2-239 d 1.10 R⊕

Metric	Earth	GJ 1002 c	Jupiter
Radius (R⊕)	1.00	1.10	11.21
Mass (M⊕)	1.00	1.36	317.83
Density (g/cm³)	5.51	5.61	1.33
Surface Gravity (g)	1.00	1.12	2.53
Insolation (S⊕)	1.00	0.26	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Minimum mass (M sin i)	1.360 M⊕	Lower bound from radial-velocity fitting.

Star Catalogue Identifiers

TIC

TIC 176287658

Gaia DR2

Gaia DR2 2441630500517079808

Gaia DR3

Gaia DR3 2441630500517079808

System

GJ 1002

Percentile among Rocky Terrestrial cohort

Radius 1.100 R⊕ · percentile 59 / cohort 570

Mass 1.360 M⊕ · percentile 53 / cohort 570

Orbital period 21.20 d · percentile 92 / cohort 567

Distance 4.85 pc · percentile 3 / cohort 566

ESI 0.686 · percentile 82 / cohort 570

Orbit & Habitability

Orbital Dynamics

Period

21.202 days

Semi-major axis

0.0738 AU

Eccentricity

—

Inclination

— °

Year Length

A year here lasts approximately 21.20 Earth days (5.8% of a terrestrial year) at a mean orbital distance of 0.0738 AU.

Eq. Temperature

182K

(-91 °C)

Insolation (S⊕)

0.26

Earth = 1.00

Earth Similarity (ESI)

0.686

0 = alien, 1 = Earth-identical

Beyond the outer HZ boundary (too cold) — surface water would be frozen. Close-orbiting tidally-locked around a cool host.

Discovery Paper

Primary reference

Su Aacute Rez Mascare Ntilde O et al. 2022

Instrument

Multiple Instruments

Publication

2022-12

Observation locale

Ground

Discovery cohort

Planets confirmed in 2022 at Multiple Observatories (12 shown).

Kepler-138 e · Rocky Terrestrial HD 93351 b · Super-Earth GJ 1002 b · Rocky Terrestrial GJ 2030 b · Sub-Neptune GJ 3929 c · Sub-Neptune HD 217786 c · Sub-Neptune HD 155918 b · Sub-Neptune HD 213519 b · Sub-Neptune HD 191939 g · Sub-Neptune GJ 514 b · Sub-Neptune HD 12235 b · Sub-Neptune HD 18143 b · Sub-Neptune

Host System: GJ 1002

Spectral Class

M-type red dwarf

Effective Temperature

3,024 K — cooler than the Sun (5,778 K)

Estimated Age

—

Stellar Radius

0.137 R☉

Stellar Mass

0.120 M☉

Metallicity [Fe/H]

-0.25

Extended Stellar Properties

Surface gravity (log g)

5.100 dex

Stellar density

55.443 g/cm³

Rotation period

126.00 days

Activity index (log R'HK)

-5.700

Metallicity ratio

[Fe/H]

Distance

4.85 parsec

Light-years 15.81 ly

V-band magnitude

13.76 mag

Voyager-speed travel 278,884 yr

Multi-band Host Photometry — 14 bands

Astrometric Data

Parallax

206.213 mas

Total Proper Motion

2,059.507 mas/yr

PM Right Ascension

-811.48 mas/yr

PM Declination

-1,892.90 mas/yr

Galactic Cartesian (pc)

x = 0.991 · y = 0.029 · z = -0.131

Equatorial (J2000)

RA 1.67646° · Dec -7.54621°

Galactic ℓ, b

92.445° · -67.730°

Ecliptic λ, β

358.515° · -7.587°

HTM-20 index

-40060782

Wikipedia → Image: Wikimedia Commons · PopePompus · CC BY-SA 4.0