Key parameters at a glance

A radius of 1.74 Earth radii
A mass of 3.69 Earth masses
Surface gravity around 1.22 g
An orbital period of 6.944 days
Semi-major axis 0.0405 AU
Equilibrium temperature 348 K (75 °C)
Distance from Earth 32.32 light-years
Earth Similarity Index 0.762
Travel time at Voyager 1 speed 570,028 years
Almost certainly tidally locked to its host star given the close orbit

GJ 3988 b Planet Profile

Physical Specs

Radius

1.74 R⊕

Radius (Jupiter)

0.156 R♃

Mass

3.69 M⊕

Mass (Jupiter)

0.012 M♃

Density

3.85 g/cm³

Surface Gravity

1.22 g (Earth)

Classification

Planet Type

Super-Earth

ESI Score 0.762

HZ Position Inner

Controversial No

Discovery

Year 2023

Method Radial Velocity

Facility Calar Alto Observatory

Telescope 3.5 m telescope

Size rank in cohort

Rank by radius

#344of 1176

top 29.2%

This planet

1.74R⊕

Super-Earth median

1.60R⊕

Nearest-size peers

Kepler-260 c 1.74 R⊕ TOI-1266 d 1.74 R⊕ Kepler-33 b 1.74 R⊕

Metric	Earth	GJ 3988 b	Jupiter
Radius (R⊕)	1.00	1.74	11.21
Mass (M⊕)	1.00	3.69	317.83
Density (g/cm³)	5.51	3.85	1.33
Surface Gravity (g)	1.00	1.22	2.53
Insolation (S⊕)	1.00	2.45	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Minimum mass (M sin i)	3.690 M⊕	Lower bound from radial-velocity fitting.

Star Catalogue Identifiers

TIC

TIC 274626553

Gaia DR2

Gaia DR2 1412645602995521920

Gaia DR3

Gaia DR3 1412645602995521920

System

GJ 3988

Percentile among Super-Earth cohort

Radius 1.740 R⊕ · percentile 70 / cohort 1176

Mass 3.690 M⊕ · percentile 64 / cohort 1176

Orbital period 6.94 d · percentile 52 / cohort 1164

Distance 9.91 pc · percentile 2 / cohort 1171

ESI 0.762 · percentile 88 / cohort 1176

Orbit & Habitability

Orbital Dynamics

Period

6.944 days

Semi-major axis

0.0405 AU

Eccentricity

0.000

Inclination

— °

Year Length

A year here lasts approximately 6.94 Earth days (1.9% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0405 AU.

Eq. Temperature

348K

(75 °C)

Insolation (S⊕)

2.45

Earth = 1.00

Earth Similarity (ESI)

0.762

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

Gorrini et al. 2023

Instrument

CARMENES

Publication

2023-10

Observation locale

Ground

Discovery cohort

Planets confirmed in 2023 at Calar Alto Observatory (3 shown).

Wolf 1069 b · Rocky Terrestrial HN Lib b · Sub-Neptune GJ 724 b · Sub-Neptune

Host System: GJ 3988

Spectral Class

M-type red dwarf

Effective Temperature

3,273 K — cooler than the Sun (5,778 K)

Estimated Age

—

Stellar Radius

0.197 R☉

Stellar Mass

0.184 M☉

Metallicity [Fe/H]

-0.12

Extended Stellar Properties

Surface gravity (log g)

4.920 dex

Stellar density

25.953 g/cm³

Systemic radial velocity

37.17 km/s

Rotational v·sin i

2.00 km/s

Rotation period

116.00 days

Metallicity ratio

[Fe/H]

Distance

9.91 parsec

Light-years 32.32 ly

V-band magnitude

13.63 mag

Voyager-speed travel 570,028 yr

Multi-band Host Photometry — 7 bands

Astrometric Data

Parallax

100.874 mas

Total Proper Motion

622.716 mas/yr

PM Right Ascension

124.58 mas/yr

PM Declination

610.13 mas/yr

Galactic Cartesian (pc)

x = -0.152 · y = -0.605 · z = 0.782

Equatorial (J2000)

RA 255.85037° · Dec 51.40898°

Galactic ℓ, b

78.480° · 37.482°

Ecliptic λ, β

237.995° · 73.277°

HTM-20 index

-276533218