Key parameters at a glance

A radius of 0.93 Earth radii
A mass of 0.95 Earth masses
Surface gravity around 1.10 g
An orbital period of 12.761 days
Semi-major axis 0.0670 AU
Equilibrium temperature 315 K (41 °C)
Distance from Earth 39.82 light-years
Earth Similarity Index 0.914
Travel time at Voyager 1 speed 702,290 years
Almost certainly tidally locked to its host star given the close orbit

Context from the literature

Gliese 12 is a red dwarf star located 39.7 light-years away in the constellation Pisces. It has about 24% the mass and 26% the radius of the Sun, and a temperature of about 3,296 K. It is an inactive star and hosts one known exoplanet.

Excerpted from Wikipedia · full article

Gliese 12 b Planet Profile

Physical Specs

Radius

0.93 R⊕

Radius (Jupiter)

0.083 R♃

Mass

0.95 M⊕

Mass (Jupiter)

0.003 M♃

Density

6.40 g/cm³

Surface Gravity

1.10 g (Earth)

Classification

Planet Type

Rocky Terrestrial

ESI Score 0.914

HZ Position Inner

Controversial No

Discovery

Year 2024

Method Transit

Facility Transiting Exoplanet Survey Satellite (TESS)

Telescope 0.1 m TESS Telescope

Size rank in cohort

Rank by radius

#391of 570

top 68.4%

This planet

0.93R⊕

Rocky Terrestrial median

1.01R⊕

Nearest-size peers

Kepler-398 b 0.93 R⊕ Kepler-1387 b 0.93 R⊕ Kepler-1421 b 0.93 R⊕

Metric	Earth	Gliese 12 b	Jupiter
Radius (R⊕)	1.00	0.93	11.21
Mass (M⊕)	1.00	0.95	317.83
Density (g/cm³)	5.51	6.40	1.33
Surface Gravity (g)	1.00	1.10	2.53
Insolation (S⊕)	1.00	1.62	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Best measured mass	0.950 M⊕	Direct mass measurement (not derived).

Star Catalogue Identifiers

TIC

TIC 52005579

Gaia DR2

Gaia DR2 2768048564768256512

Gaia DR3

Gaia DR3 2768048564768256512

System

Gliese 12

Percentile among Rocky Terrestrial cohort

Radius 0.930 R⊕ · percentile 31 / cohort 570

Mass 0.950 M⊕ · percentile 35 / cohort 570

Orbital period 12.76 d · percentile 85 / cohort 567

Distance 12.21 pc · percentile 6 / cohort 566

ESI 0.914 · percentile 91 / cohort 570

Orbit & Habitability

Orbital Dynamics

Period

12.761 days

Semi-major axis

0.0670 AU

Eccentricity

0.240

Inclination

89.25 °

Year Length

A year here lasts approximately 12.76 Earth days (3.5% of a terrestrial year) on a mildly elliptical path at a mean orbital distance of 0.0670 AU.

Transit Fingerprint

Depth

0.122 %

Duration

1.200 h

Impact parameter b

0.750

Rp / R★

0.032300

Transit midpoint (BJD)

2,460,033.1635

Photometric dip

Transit produces a flux drop of 1,215 ppm lasting ≈ 1.20 h.

Extended Orbital Architecture

Planet / star radius ratio

0.032300

Semi-major axis / stellar radius

55.200

Impact parameter (b)

0.750

RV semi-amplitude (K)

0.670 m/s

Transit mid-time (BJD)

2,460,033.1635

Long. of periastron (ω)

-16.00°

Angular separation (arcsec)

5.49000

Eq. Temperature

315K

(41 °C)

Insolation (S⊕)

1.62

Earth = 1.00

Earth Similarity (ESI)

0.914

0 = alien, 1 = Earth-identical

Inside the inner HZ boundary (too hot for liquid water) — liquid water is physically possible with adequate atmospheric pressure. Close-orbiting tidally-locked around a cool host.

Detection Signatures

Transit photometry

A transit dip has been observed from at least one telescope.

Radial velocity

Stellar wobble has been measured spectroscopically.

Discovery Paper

Primary reference

Kuzuhara et al. 2024

Instrument

TESS CCD Array

Publication

2024-06

Observation locale

Space

Discovery cohort

Planets confirmed in 2024 at Transiting Exoplanet Survey Satellite (TESS) (12 shown).

TOI-6002 b · Super-Earth TOI-5713 b · Super-Earth TOI-4336 A b · Sub-Neptune TOI-406.01 · Sub-Neptune TOI-1224 c · Sub-Neptune LHS 1678 d · Rocky Terrestrial TOI-2088 b · Sub-Neptune TOI-2120 b · Sub-Neptune TOI-1806.01 · Sub-Neptune TOI-4633 c · Sub-Neptune TOI-260 b · Super-Earth TOI-663 d · Super-Earth

Host System: Gliese 12

Spectral Class

M-type red dwarf

Effective Temperature

3,328 K — cooler than the Sun (5,778 K)

Estimated Age

7.00 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

0.265 R☉

Stellar Mass

0.255 M☉

Metallicity [Fe/H]

-0.24

Extended Stellar Properties

Surface gravity (log g)

5.250 dex

Stellar density

19.518 g/cm³

Systemic radial velocity

51.21 km/s

Rotational v·sin i

2.00 km/s

Rotation period

85.00 days

Activity index (log R'HK)

-5.620

Metallicity ratio

[Fe/H]

Distance

12.21 parsec

Light-years 39.82 ly

V-band magnitude

12.60 mag

Voyager-speed travel 702,290 yr

Multi-band Host Photometry — 7 bands

Astrometric Data

Parallax

81.871 mas

Total Proper Motion

700.270 mas/yr

PM Right Ascension

618.00 mas/yr

PM Declination

329.32 mas/yr

Galactic Cartesian (pc)

x = 0.970 · y = 0.067 · z = 0.234

Equatorial (J2000)

RA 3.95791° · Dec 13.55762°

Galactic ℓ, b

109.835° · -48.407°

Ecliptic λ, β

9.066° · 10.859°

HTM-20 index

779842208

Wikipedia → Image: Wikimedia Commons · NASA/JPL-Caltech/R. Hurt (Caltech-IPAC) · Public domain