Key parameters at a glance
- A radius of 2.38 Earth radii
- A mass of 6.27 Earth masses
- Surface gravity around 1.11 g
- An orbital period of 111.740 days
- Semi-major axis 0.2700 AU
- Equilibrium temperature 150 K (-123 °C)
- Distance from Earth 27.24 light-years
- Earth Similarity Index 0.462
- Travel time at Voyager 1 speed 480,357 years
Context from the literature
GJ 1289 b is a sub-Neptune exoplanet orbiting the red dwarf star GJ 1289, located approximately 8.86 parsecs from the Sun. It was discovered using radial-velocity measurements with the near-infrared spectropolarimeter SPIRou at the Canada–France–Hawaii Telescope over multiple years, revealing a minimum mass of 6.27 ± 1.25 Earth masses and a nearly circular orbit with a period of 111.74 days. The host star, an M4.5V fully convective red dwarf with a mass of 0.21 solar masses, exhibits a strong large-scale dipolar magnetic field of 200–240 G and a rotation period of ~73.7 days, which is distinct from the planet's orbital period.
Excerpted from Wikipedia · full article
GJ 1289 b Planet Profile
Physical Specs
Classification
Planet Type
Sub-Neptune
Discovery
Size rank in cohort
Rank by radius
#1365of 1978
top 69.0%
This planet
2.38R⊕
Sub-Neptune median
2.71R⊕
Nearest-size peers
| Metric | Earth | GJ 1289 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 2.38 | 11.21 |
| Mass (M⊕) | 1.00 | 6.27 | 317.83 |
| Density (g/cm³) | 5.51 | 2.56 | 1.33 |
| Surface Gravity (g) | 1.00 | 1.11 | 2.53 |
| Insolation (S⊕) | 1.00 | — | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Minimum mass (M sin i) | 6.270 M⊕ | Lower bound from radial-velocity fitting. |
Star Catalogue Identifiers
TIC
TIC 352593978
Gaia DR2
Gaia DR2 2879455480941956736
Gaia DR3
Gaia DR3 2879455480942629248
System
GJ 1289
Percentile among Sub-Neptune cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 111.74 Earth days (30.6% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.2700 AU.
Extended Orbital Architecture
RV semi-amplitude (K)
2.370 m/s
Transit mid-time (BJD)
2,459,403.2000
Long. of periastron (ω)
0.00°
Angular separation (arcsec)
32.30000
Eq. Temperature
150K
(-123 °C)
Insolation (S⊕)
—
Earth = 1.00
Earth Similarity (ESI)
0.462
0 = alien, 1 = Earth-identical
Insufficient insolation data — surface water would be frozen.
Discovery Paper
Primary reference
Moutou et al. 2024Instrument
Multiple Instruments
Publication
2024-08
Observation locale
Ground
Discovery cohort
Planets confirmed in 2024 at Multiple Observatories (12 shown).
Host System: GJ 1289
Spectral Class
M-type red dwarf
Effective Temperature
3,296 K — cooler than the Sun (5,778 K)
Estimated Age
—
Stellar Radius
0.245 R☉
Stellar Mass
0.210 M☉
Metallicity [Fe/H]
0.02
Extended Stellar Properties
Surface gravity (log g)
4.993 dex
Stellar density
20.655 g/cm³
Rotation period
73.66 days
Metallicity ratio
[M/H]
Multi-band Host Photometry — 6 bands
Astrometric Data
Parallax
119.711 mas
Total Proper Motion
954.349 mas/yr
PM Right Ascension
942.27 mas/yr
PM Declination
-151.39 mas/yr
Galactic Cartesian (pc)
x = 0.801 · y = -0.059 · z = 0.595
Equatorial (J2000)
RA 355.78135° · Dec 36.53633°
Galactic ℓ, b
107.923° · -24.336°
Ecliptic λ, β
12.832° · 34.731°
HTM-20 index
-1559455053
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