Key parameters at a glance

A radius of 13.60 Earth radii
A mass of 413.18 Earth masses
Surface gravity around 2.23 g
An orbital period of 272.700 days
Semi-major axis 0.7100 AU
Distance from Earth 124.36 light-years
Earth Similarity Index 0.331
Travel time at Voyager 1 speed 2,193,089 years

GJ 2126 b Planet Profile

Physical Specs

Radius

13.60 R⊕

Radius (Jupiter)

1.220 R♃

Mass

413.18 M⊕

Mass (Jupiter)

1.300 M♃

Density

0.90 g/cm³

Surface Gravity

2.23 g (Earth)

Classification

Planet Type

Gas Giant

ESI Score 0.331

HZ Position Unknown

Controversial No

Discovery

Year 2025

Method Radial Velocity

Facility La Silla Observatory

Telescope 3.6 m ESO Telescope

Size rank in cohort

Rank by radius

#609of 1771

top 34.3%

This planet

13.60R⊕

Gas Giant median

13.52R⊕

Nearest-size peers

HD 19994 b 13.60 R⊕ HD 205739 b 13.60 R⊕ HD 79498 b 13.60 R⊕

Metric	Earth	GJ 2126 b	Jupiter
Radius (R⊕)	1.00	13.60	11.21
Mass (M⊕)	1.00	413.18	317.83
Density (g/cm³)	5.51	0.90	1.33
Surface Gravity (g)	1.00	2.23	2.53
Insolation (S⊕)	1.00	—	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Minimum mass (M sin i)	413.177 M⊕	Lower bound from radial-velocity fitting.

Star Catalogue Identifiers

HIP

HIP 83941

TIC

TIC 44082776

Gaia DR2

Gaia DR2 5977270148650362112

Gaia DR3

Gaia DR3 5977270148650362112

System

GJ 2126

Percentile among Gas Giant cohort

Radius 13.600 R⊕ · percentile 63 / cohort 1771

Mass 413.177 M⊕ · percentile 43 / cohort 1747

Orbital period 272.70 d · percentile 60 / cohort 1533

Distance 38.13 pc · percentile 13 / cohort 1759

ESI 0.331 · percentile 65 / cohort 1771

Orbit & Habitability

Orbital Dynamics

Period

272.700 days

Semi-major axis

0.7100 AU

Eccentricity

0.850

Inclination

— °

Year Length

A year here lasts approximately 272.70 Earth days (74.7% of a terrestrial year) on a highly eccentric trajectory at a mean orbital distance of 0.7100 AU.

Eq. Temperature

—

Insolation (S⊕)

—

Earth = 1.00

Earth Similarity (ESI)

0.331

0 = alien, 1 = Earth-identical

Discovery Paper

Primary reference

Schorr et al. 2025

Instrument

HARPS Spectrograph

Publication

2025-02

Observation locale

Ground

Discovery cohort

Planets confirmed in 2025 at La Silla Observatory (12 shown).

Proxima Cen d · Rocky Terrestrial TOI-1203 c · Sub-Neptune HD 23079 c · Sub-Neptune HD 196067 c · Sub-Neptune HD 87816 b · Gas Giant HD 102888 b · Gas Giant HD 94890 c · Gas Giant TOI-756 c · Gas Giant TOI-1203 e · Neptune-like HD 94890 b · Gas Giant HD 87816 c · Gas Giant HD 28471 d · Sub-Neptune

Host System: GJ 2126

Spectral Class

M-type red dwarf

Effective Temperature

4,159 K — cooler than the Sun (5,778 K)

Estimated Age

—

Stellar Radius

0.728 R☉

Stellar Mass

0.650 M☉

Metallicity [Fe/H]

0.60

Extended Stellar Properties

Surface gravity (log g)

4.527 dex

Stellar density

2.377 g/cm³

Metallicity ratio

[Fe/H]

Distance

38.13 parsec

Light-years 124.36 ly

V-band magnitude

10.70 mag

Voyager-speed travel 2,193,089 yr

Multi-band Host Photometry — 11 bands

Astrometric Data

Parallax

26.198 mas

Total Proper Motion

102.064 mas/yr

PM Right Ascension

-46.67 mas/yr

PM Declination

-90.77 mas/yr

Galactic Cartesian (pc)

x = -0.178 · y = -0.795 · z = -0.579

Equatorial (J2000)

RA 257.36068° · Dec -35.39172°

Galactic ℓ, b

350.380° · 2.765°

Ecliptic λ, β

259.472° · -12.413°

HTM-20 index

665259867

Similar Worlds

AT2021ueyL b

Gas Giant · M-type red dwarf

Radius 13.60 R⊕ · 3,392.0 ly

GJ 317 c

Gas Giant · M-type red dwarf

Radius 13.60 R⊕ · 49.6 ly

VHS J125601.92-125723.9 b

Gas Giant · M-type red dwarf

Radius 13.67 R⊕ · 41.4 ly

TOI-4201 b

Gas Giant · M-type red dwarf

Radius 13.67 R⊕ · 616.5 ly

GJ 179 b

Gas Giant · M-type red dwarf

Radius 13.80 R⊕ · 40.3 ly

GJ 832 b

Gas Giant · M-type red dwarf

Radius 13.80 R⊕ · 16.2 ly

Explore Related Categories

Gas Giant Planets Radial Velocity Discoveries La Silla Observatory Mission M-type red dwarf Hosts