Key parameters at a glance

A radius of 1.09 Earth radii
A mass of 1.75 Earth masses
Surface gravity around 1.47 g
An orbital period of 2.616 days
Semi-major axis 0.0252 AU
Equilibrium temperature 568 K (295 °C)
Distance from Earth 51.56 light-years
Earth Similarity Index 0.537
Travel time at Voyager 1 speed 909,325 years
Almost certainly tidally locked to its host star given the close orbit

Context from the literature

GJ 3929 b is a confirmed exoplanet located 52 light-years away orbiting the red dwarf star GJ 3929. It is an Earth-sized planet, having a radius only 9% larger than that of Earth. It orbits its star at a distance of 0.0252 astronomical units (3,770,000 km), being located in the "Venus zone" of its star, and completes one orbit around it every 2 days and 15 hours. Because of the proximity of its star, GJ 3929 b has an equilibrium temperature of around 300 °C and receiving planetary insolation 17 times more intense than Earth receives from the Sun.

Excerpted from Wikipedia · full article

1 sibling around GJ 3929

GJ 3929 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 3929 b this	Rocky Terrestrial	1.09	1.75	2.616	568	2022
GJ 3929 c	Sub-Neptune	2.26	5.71	15.040	317	2022

GJ 3929 b Planet Profile

Physical Specs

Radius

1.09 R⊕

Radius (Jupiter)

0.097 R♃

Mass

1.75 M⊕

Mass (Jupiter)

0.006 M♃

Density

7.30 g/cm³

Surface Gravity

1.47 g (Earth)

Classification

Planet Type

Rocky Terrestrial

ESI Score 0.537

HZ Position Inner

Controversial No

Discovery

Year 2022

Method Transit

Facility Transiting Exoplanet Survey Satellite (TESS)

Telescope 0.1 m TESS Telescope

Size rank in cohort

Rank by radius

#240of 570

top 41.9%

This planet

1.09R⊕

Rocky Terrestrial median

1.01R⊕

Nearest-size peers

TOI-5720 b 1.09 R⊕ Kepler-115 b 1.09 R⊕ Kepler-212 b 1.09 R⊕

Metric	Earth	GJ 3929 b	Jupiter
Radius (R⊕)	1.00	1.09	11.21
Mass (M⊕)	1.00	1.75	317.83
Density (g/cm³)	5.51	7.30	1.33
Surface Gravity (g)	1.00	1.47	2.53
Insolation (S⊕)	1.00	17.30	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Best measured mass	1.750 M⊕	Direct mass measurement (not derived).
Minimum mass (M sin i)	1.210 M⊕	Lower bound from radial-velocity fitting.

Star Catalogue Identifiers

TIC

TIC 188589164

Gaia DR2

Gaia DR2 1372215976327300480

Gaia DR3

Gaia DR3 1372215976327300480

System

GJ 3929

Percentile among Rocky Terrestrial cohort

Radius 1.090 R⊕ · percentile 56 / cohort 570

Mass 1.750 M⊕ · percentile 71 / cohort 570

Orbital period 2.62 d · percentile 30 / cohort 567

Distance 15.81 pc · percentile 8 / cohort 566

ESI 0.537 · percentile 73 / cohort 570

Orbit & Habitability

Orbital Dynamics

Period

2.616 days

Semi-major axis

0.0252 AU

Eccentricity

0.000

Inclination

88.44 °

Year Length

A year here lasts approximately 2.62 Earth days (0.7% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0252 AU.

Transit Fingerprint

Depth

0.112 %

Duration

1.190 h

Impact parameter b

0.110

Rp / R★

0.015600

Transit midpoint (BJD)

2,458,956.3962

Photometric dip

Transit produces a flux drop of 1,121 ppm lasting ≈ 1.19 h.

Extended Orbital Architecture

Planet / star radius ratio

0.015600

Semi-major axis / stellar radius

16.800

Impact parameter (b)

0.110

RV semi-amplitude (K)

1.770 m/s

Transit mid-time (BJD)

2,458,956.3962

Long. of periastron (ω)

90.00°

Angular separation (arcsec)

1.59000

Eq. Temperature

568K

(295 °C)

Insolation (S⊕)

17.30

Earth = 1.00

Earth Similarity (ESI)

0.537

0 = alien, 1 = Earth-identical

Inside the inner HZ boundary (too hot for liquid water) — the surface is too hot to retain surface water. 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

Kemmer et al. 2022

Instrument

TESS CCD Array

Publication

2022-02

Observation locale

Space

Discovery cohort

Planets confirmed in 2022 at Transiting Exoplanet Survey Satellite (TESS) (12 shown).

TOI-1452 b · Super-Earth TOI-712 d · Sub-Neptune TOI-1468 c · Sub-Neptune TOI-2136 b · Sub-Neptune LTT 1445 A c · Rocky Terrestrial TOI-712 c · Sub-Neptune LP 890-9 b · Super-Earth TOI-2081 b · Sub-Neptune HD 260655 c · Super-Earth HD 73583 c · Sub-Neptune TOI-1759 b · Sub-Neptune TOI-1246 e · Sub-Neptune

Host System: GJ 3929

Spectral Class

M-type red dwarf

Effective Temperature

3,384 K — cooler than the Sun (5,778 K)

Estimated Age

7.10 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

0.320 R☉

Stellar Mass

0.313 M☉

Metallicity [Fe/H]

-0.02

Extended Stellar Properties

Surface gravity (log g)

4.890 dex

Stellar density

13.300 g/cm³

Systemic radial velocity

10.27 km/s

Rotational v·sin i

2.00 km/s

Rotation period

122.00 days

Metallicity ratio

[Fe/H]

Distance

15.81 parsec

Light-years 51.56 ly

V-band magnitude

12.68 mag

Voyager-speed travel 909,325 yr

Multi-band Host Photometry — 12 bands

Astrometric Data

Parallax

63.224 mas

Total Proper Motion

348.987 mas/yr

PM Right Ascension

-143.28 mas/yr

PM Declination

318.22 mas/yr

Galactic Cartesian (pc)

x = -0.413 · y = -0.703 · z = 0.579

Equatorial (J2000)

RA 239.57757° · Dec 35.40811°

Galactic ℓ, b

56.664° · 49.597°

Ecliptic λ, β

225.110° · 54.209°

HTM-20 index

1842549599

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