Confirmed Exoplanet Discovered 2025

TOI-6109 c

A neptune-like orbiting the g-type yellow (sun-like) TOI-6109, located approximately 494.9 light-years from Earth.

Key parameters at a glance

  • A radius of 4.83 Earth radii
  • A mass of 20.80 Earth masses
  • Surface gravity around 0.89 g
  • An orbital period of 8.539 days
  • Semi-major axis 0.0786 AU
  • Equilibrium temperature 786 K (513 °C)
  • Distance from Earth 494.90 light-years
  • Earth Similarity Index 0.244
  • Travel time at Voyager 1 speed 8,727,607 years

1 sibling around TOI-6109

TOI-6109 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
TOI-6109 b Neptune-like 4.87 21.10 5.690 700 2025
TOI-6109 c this Neptune-like 4.83 20.80 8.539 786 2025

TOI-6109 c Planet Profile

Physical Specs

Radius
4.83 R⊕
Radius (Jupiter)
0.431 R♃
Mass
20.80 M⊕
Mass (Jupiter)
0.066 M♃
Density
1.01 g/cm³
Surface Gravity
0.89 g (Earth)

Classification

Planet Type

Neptune-like

ESI Score 0.244
HZ Position Inner
Controversial No

Discovery

Year 2025
Method Transit
Facility Transiting Exoplanet Survey Satellite (TESS)
Telescope 0.1 m TESS Telescope

Size rank in cohort

Rank by radius

#409of 574

top 71.1%

This planet

4.83R⊕

Neptune-like median

6.39R⊕

Nearest-size peers

Metric Earth TOI-6109 c Jupiter
Radius (R⊕)1.004.8311.21
Mass (M⊕)1.0020.80317.83
Density (g/cm³)5.511.011.33
Surface Gravity (g)1.000.892.53
Insolation (S⊕)1.0063.390.037

Star Catalogue Identifiers

TIC

TIC 384984325

Gaia DR2

Gaia DR2 241035591876195328

Gaia DR3

Gaia DR3 241035596174886016

System

TOI-6109

Percentile among Neptune-like cohort

Radius 4.833 R⊕ · percentile 29 / cohort 574
Mass 20.800 M⊕ · percentile 32 / cohort 574
Orbital period 8.54 d · percentile 33 / cohort 524
Distance 151.74 pc · percentile 33 / cohort 572
ESI 0.244 · percentile 39 / cohort 574

Orbit & Habitability

Orbital Dynamics

Period
8.539 days
Semi-major axis
0.0786 AU
Eccentricity
Inclination
87.20 °

Year Length

A year here lasts approximately 8.54 Earth days (2.3% of a terrestrial year) at a mean orbital distance of 0.0786 AU.

Transit Fingerprint

Depth

0.173 %

Duration

2.337 h

Impact parameter b

0.806

Rp / R★

0.043400

Transit midpoint (BJD)

2,458,798.0657

Photometric dip

Transit produces a flux drop of 1,730 ppm lasting ≈ 2.34 h.

Extended Orbital Architecture

Planet / star radius ratio

0.043400

Semi-major axis / stellar radius

16.565

Impact parameter (b)

0.806

Transit mid-time (BJD)

2,458,798.0657

Angular separation (arcsec)

0.51800

Eq. Temperature

786K

(513 °C)

Insolation (S⊕)

63.39

Earth = 1.00

Earth Similarity (ESI)

0.244

0 = alien, 1 = Earth-identical

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

Detection Signatures

Transit photometry

A transit dip has been observed from at least one telescope.

Transit timing variations

Gravitational interactions from neighbours have been detected.

Discovery Paper

Primary reference

Dattilo et al. 2025

Instrument

TESS CCD Array

Publication

2025-09

Observation locale

Space

Host System: TOI-6109

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,660 K — cooler than the Sun (5,778 K)

Estimated Age

0.07 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

1.021 R☉

Stellar Mass

1.030 M☉

Metallicity [Fe/H]

0.09

Extended Stellar Properties

Surface gravity (log g)

4.450 dex

Stellar density

1.193 g/cm³

Systemic radial velocity

2.33 km/s

Rotational v·sin i

18.20 km/s

Rotation period

3.02 days

Metallicity ratio

[M/H]

Distance
151.74 parsec
Light-years 494.90 ly
V-band magnitude
11.05 mag
Voyager-speed travel 8,727,607 yr

Multi-band Host Photometry — 11 bands

9.011.611.64B11.05V10.83Gaia10.36TESS9.66J9.32H9.25K9.23W19.26W29.22W38.99W4

Astrometric Data

Parallax

6.562 mas

Total Proper Motion

39.475 mas/yr

PM Right Ascension

27.00 mas/yr

PM Declination

-28.80 mas/yr

Galactic Cartesian (pc)

x = 0.472 · y = 0.565 · z = 0.677

Equatorial (J2000)

RA 50.13192° · Dec 42.60696°

Galactic ℓ, b

150.072° · -12.273°

Ecliptic λ, β

59.072° · 23.353°

HTM-20 index

-84450772

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