Key parameters at a glance

A radius of 1.10 Earth radii
A mass of 1.37 Earth masses
Surface gravity around 1.13 g
An orbital period of 5.454 days
Semi-major axis 0.0297 AU
Equilibrium temperature 322 K (49 °C)
Distance from Earth 34.66 light-years
Earth Similarity Index 0.904
Travel time at Voyager 1 speed 611,222 years
Almost certainly tidally locked to its host star given the close orbit

G 261-6 b Planet Profile

Physical Specs

Radius

1.10 R⊕

Radius (Jupiter)

0.098 R♃

Mass

1.37 M⊕

Mass (Jupiter)

0.004 M♃

Density

5.66 g/cm³

Surface Gravity

1.13 g (Earth)

Classification

Planet Type

Rocky Terrestrial

ESI Score 0.904

HZ Position Inner

Controversial No

Discovery

Year 2025

Method Radial Velocity

Facility Calar Alto Observatory

Telescope 3.5 m telescope

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	G 261-6 b	Jupiter
Radius (R⊕)	1.00	1.10	11.21
Mass (M⊕)	1.00	1.37	317.83
Density (g/cm³)	5.51	5.66	1.33
Surface Gravity (g)	1.00	1.13	2.53
Insolation (S⊕)	1.00	1.80	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Minimum mass (M sin i)	1.370 M⊕	Lower bound from radial-velocity fitting.

Star Catalogue Identifiers

TIC

TIC 420130591

Gaia DR2

Gaia DR2 2289304297045379456

Gaia DR3

Gaia DR3 2289304297045379456

System

G 261-6

Percentile among Rocky Terrestrial cohort

Radius 1.100 R⊕ · percentile 59 / cohort 570

Mass 1.370 M⊕ · percentile 54 / cohort 570

Orbital period 5.45 d · percentile 58 / cohort 567

Distance 10.63 pc · percentile 6 / cohort 566

ESI 0.904 · percentile 91 / cohort 570

Orbit & Habitability

Orbital Dynamics

Period

5.454 days

Semi-major axis

0.0297 AU

Eccentricity

0.000

Inclination

— °

Year Length

A year here lasts approximately 5.45 Earth days (1.5% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0297 AU.

Eq. Temperature

322K

(49 °C)

Insolation (S⊕)

1.80

Earth = 1.00

Earth Similarity (ESI)

0.904

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.

Discovery Paper

Primary reference

Kaminski et al. 2025

Instrument

CARMENES

Publication

2025-04

Observation locale

Ground

Discovery cohort

Planets confirmed in 2025 at Calar Alto Observatory (8 shown).

G 192-15 b · Rocky Terrestrial G 268-110 b · Rocky Terrestrial KOBE-1 c · Sub-Neptune TOI-2093 b · Sub-Neptune KOBE-1 b · Sub-Neptune GJ 9773 b · Gas Giant G 192-15 c · Sub-Neptune GJ 508.2 b · Unclassified

Host System: G 261-6

Spectral Class

M-type red dwarf

Effective Temperature

2,907 K — cooler than the Sun (5,778 K)

Estimated Age

—

Stellar Radius

0.153 R☉

Stellar Mass

0.118 M☉

Metallicity [Fe/H]

—

Extended Stellar Properties

Surface gravity (log g)

5.165 dex

Stellar density

49.102 g/cm³

Rotation period

114.00 days

Distance

10.63 parsec

Light-years 34.66 ly

V-band magnitude

15.75 mag

Voyager-speed travel 611,222 yr

Multi-band Host Photometry — 6 bands

Astrometric Data

Parallax

94.074 mas

Total Proper Motion

698.242 mas/yr

PM Right Ascension

369.64 mas/yr

PM Declination

592.37 mas/yr

Galactic Cartesian (pc)

x = 0.090 · y = -0.233 · z = 0.968

Equatorial (J2000)

RA 291.07432° · Dec 75.55584°

Galactic ℓ, b

107.229° · 24.195°

Ecliptic λ, β

62.409° · 78.833°

HTM-20 index

624912639