Key parameters at a glance
- A radius of 2.26 Earth radii
- A mass of 5.71 Earth masses
- Surface gravity around 1.12 g
- An orbital period of 15.040 days
- Semi-major axis 0.0810 AU
- Equilibrium temperature 317 K (44 °C)
- Distance from Earth 51.56 light-years
- Earth Similarity Index 0.745
- 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, also known as Gliese 3929 and TOI-2013, is a red dwarf star located 51.6 light-years from Earth, in the constellation Corona Borealis. With an apparent magnitude of 12, it is not visible to the naked eye. In 2022, two exoplanets were detected orbiting the star.
Excerpted from Wikipedia · full article
1 sibling around GJ 3929
GJ 3929 c 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 | Rocky Terrestrial | 1.09 | 1.75 | 2.616 | 568 | 2022 |
| GJ 3929 c this | Sub-Neptune | 2.26 | 5.71 | 15.040 | 317 | 2022 |
GJ 3929 c Planet Profile
Physical Specs
Classification
Planet Type
Sub-Neptune
Discovery
Size rank in cohort
Rank by radius
#1572of 1978
top 79.4%
This planet
2.26R⊕
Sub-Neptune median
2.71R⊕
Nearest-size peers
| Metric | Earth | GJ 3929 c | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 2.26 | 11.21 |
| Mass (M⊕) | 1.00 | 5.71 | 317.83 |
| Density (g/cm³) | 5.51 | 2.72 | 1.33 |
| Surface Gravity (g) | 1.00 | 1.12 | 2.53 |
| Insolation (S⊕) | 1.00 | 1.68 | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Minimum mass (M sin i) | 5.710 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 Sub-Neptune cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 15.04 Earth days (4.1% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0810 AU.
Extended Orbital Architecture
RV semi-amplitude (K)
3.220 m/s
Transit mid-time (BJD)
2,459,070.9000
Long. of periastron (ω)
90.00°
Angular separation (arcsec)
5.12000
Eq. Temperature
317K
(44 °C)
Insolation (S⊕)
1.68
Earth = 1.00
Earth Similarity (ESI)
0.745
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
Beard et al. 2022Instrument
Multiple Instruments
Publication
2022-07
Observation locale
Ground
Discovery cohort
Planets confirmed in 2022 at Multiple Observatories (12 shown).
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]
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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