Key parameters at a glance

A radius of 1.03 Earth radii
A mass of 1.08 Earth masses
Surface gravity around 1.02 g
An orbital period of 10.347 days
Semi-major axis 0.0457 AU
Equilibrium temperature 231 K (-42 °C)
Distance from Earth 15.81 light-years
Earth Similarity Index 0.845
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 b is a potentially habitable exoplanet located 16 light-years away, in the constellation of Cetus. The planet, which has an Earth Similarity Index of 86%, is in the habitable zone of its parent star. GJ 1002 b has a minimum mass of 1.08 Earth masses and is estimated by the Planetary Habitability Laboratory to have 1.03 times the radius of Earth and a surface temperature of 261 Kelvin.

Excerpted from Wikipedia · full article

1 sibling around GJ 1002

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

GJ 1002 b Planet Profile

Physical Specs

Radius

1.03 R⊕

Radius (Jupiter)

0.092 R♃

Mass

1.08 M⊕

Mass (Jupiter)

0.003 M♃

Density

5.43 g/cm³

Surface Gravity

1.02 g (Earth)

Classification

Planet Type

Rocky Terrestrial

ESI Score 0.845

HZ Position Habitable

Controversial No

Discovery

Year 2022

Method Radial Velocity

Facility Multiple Observatories

Telescope Multiple Telescopes

Size rank in cohort

Rank by radius

#297of 570

top 51.9%

This planet

1.03R⊕

Rocky Terrestrial median

1.01R⊕

Nearest-size peers

Kepler-395 b 1.03 R⊕ Kepler-387 b 1.03 R⊕ Kepler-1398 c 1.03 R⊕

Metric	Earth	GJ 1002 b	Jupiter
Radius (R⊕)	1.00	1.03	11.21
Mass (M⊕)	1.00	1.08	317.83
Density (g/cm³)	5.51	5.43	1.33
Surface Gravity (g)	1.00	1.02	2.53
Insolation (S⊕)	1.00	0.67	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Minimum mass (M sin i)	1.080 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 1.030 R⊕ · percentile 46 / cohort 570

Mass 1.080 M⊕ · percentile 41 / cohort 570

Orbital period 10.35 d · percentile 79 / cohort 567

Distance 4.85 pc · percentile 3 / cohort 566

ESI 0.845 · percentile 88 / cohort 570

Orbit & Habitability

Orbital Dynamics

Period

10.347 days

Semi-major axis

0.0457 AU

Eccentricity

—

Inclination

— °

Year Length

A year here lasts approximately 10.35 Earth days (2.8% of a terrestrial year) at a mean orbital distance of 0.0457 AU.

Eq. Temperature

231K

(-42 °C)

Insolation (S⊕)

0.67

Earth = 1.00

Earth Similarity (ESI)

0.845

0 = alien, 1 = Earth-identical

Within the conservative habitable zone — 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 2030 b · Sub-Neptune GJ 3929 c · Sub-Neptune HD 217786 c · Sub-Neptune GJ 1002 c · Rocky Terrestrial 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

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