Confirmed Exoplanet Discovered 2025

GJ 9773 b

A gas giant orbiting the m-type red dwarf GJ 9773, located approximately 51.9 light-years from Earth.

Key parameters at a glance

  • A radius of 14.20 Earth radii
  • A mass of 172.58 Earth masses
  • Surface gravity around 0.86 g
  • An orbital period of 2,965.000 days
  • Semi-major axis 2.9210 AU
  • Distance from Earth 51.93 light-years
  • Earth Similarity Index 0.259
  • Travel time at Voyager 1 speed 915,744 years

GJ 9773 b Planet Profile

Physical Specs

Radius
14.20 R⊕
Radius (Jupiter)
1.260 R♃
Mass
172.58 M⊕
Mass (Jupiter)
0.543 M♃
Density
0.33 g/cm³
Surface Gravity
0.86 g (Earth)

Classification

Planet Type

Gas Giant

ESI Score 0.259
HZ Position Unknown
Controversial No

Discovery

Year 2025
Method Radial Velocity
Facility Calar Alto Observatory
Telescope 3.5 m telescope

Size rank in cohort

Rank by radius

#334of 1771

top 18.8%

This planet

14.20R⊕

Gas Giant median

13.52R⊕

Nearest-size peers

Metric Earth GJ 9773 b Jupiter
Radius (R⊕)1.0014.2011.21
Mass (M⊕)1.00172.58317.83
Density (g/cm³)5.510.331.33
Surface Gravity (g)1.000.862.53
Insolation (S⊕)1.000.037

Alternative Mass Estimates

Method Value Interpretation
Minimum mass (M sin i) 172.581 M⊕ Lower bound from radial-velocity fitting.

Star Catalogue Identifiers

HIP

HIP 109638

TIC

TIC 468309671

Gaia DR2

Gaia DR2 2723557788822526720

Gaia DR3

Gaia DR3 2723557788822526720

System

GJ 9773

Percentile among Gas Giant cohort

Radius 14.200 R⊕ · percentile 79 / cohort 1771
Mass 172.581 M⊕ · percentile 15 / cohort 1747
Orbital period 2,965.00 d · percentile 88 / cohort 1533
Distance 15.92 pc · percentile 2 / cohort 1759
ESI 0.259 · percentile 47 / cohort 1771

Orbit & Habitability

Orbital Dynamics

Period
2,965.000 days
Semi-major axis
2.9210 AU
Eccentricity
0.218
Inclination
°

Year Length

A year here lasts about 8.12 Earth years on a mildly elliptical path at a mean orbital distance of 2.9210 AU.

Extended Orbital Architecture

RV semi-amplitude (K)

15.110 m/s

Transit mid-time (BJD)

2,459,362.0000

Long. of periastron (ω)

99.00°

Angular separation (arcsec)

183.00000

Eq. Temperature

 

Insolation (S⊕)

Earth = 1.00

Earth Similarity (ESI)

0.259

0 = alien, 1 = Earth-identical

Discovery Paper

Primary reference

Morales et al. 2025

Instrument

CARMENES

Publication

2025-07

Observation locale

Ground

Host System: GJ 9773

Spectral Class

M-type red dwarf

Effective Temperature

3,528 K — cooler than the Sun (5,778 K)

Estimated Age

Stellar Radius

0.362 R☉

Stellar Mass

0.358 M☉

Metallicity [Fe/H]

-0.20

Extended Stellar Properties

Surface gravity (log g)

4.847 dex

Stellar density

9.548 g/cm³

Rotational v·sin i

2.00 km/s

Rotation period

56.00 days

Metallicity ratio

[Fe/H]

Distance
15.92 parsec
Light-years 51.93 ly
V-band magnitude
12.03 mag
Voyager-speed travel 915,744 yr

Multi-band Host Photometry — 8 bands

7.513.513.54B12.03V10.90Gaia9.73TESS9.58Ic8.28J7.68H7.47K

Astrometric Data

Parallax

62.781 mas

Total Proper Motion

678.873 mas/yr

PM Right Ascension

106.80 mas/yr

PM Declination

-670.42 mas/yr

Galactic Cartesian (pc)

x = 0.882 · y = -0.447 · z = 0.149

Equatorial (J2000)

RA 333.15023° · Dec 8.55034°

Galactic ℓ, b

70.112° · -37.536°

Ecliptic λ, β

338.322° · 18.305°

HTM-20 index

1650008810

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