Key parameters at a glance

A radius of 6.61 Earth radii
A mass of 89.00 Earth masses
Surface gravity around 2.04 g
An orbital period of 25.868 days
Semi-major axis 0.1650 AU
Equilibrium temperature 643 K (370 °C)
Distance from Earth 1,127.39 light-years
Earth Similarity Index 0.261
Travel time at Voyager 1 speed 19,881,479 years

TOI-4940 b Planet Profile

Physical Specs

Radius

6.61 R⊕

Radius (Jupiter)

0.590 R♃

Mass

89.00 M⊕

Mass (Jupiter)

0.280 M♃

Density

— g/cm³

Surface Gravity

2.04 g (Earth)

Classification

Planet Type

Neptune-like

ESI Score 0.261

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

#229of 574

top 39.7%

This planet

6.61R⊕

Neptune-like median

6.39R⊕

Nearest-size peers

TOI-5108 b 6.60 R⊕ Kepler-1624 b 6.59 R⊕ K2-19 b 6.59 R⊕

Metric	Earth	TOI-4940 b	Jupiter
Radius (R⊕)	1.00	6.61	11.21
Mass (M⊕)	1.00	89.00	317.83
Density (g/cm³)	5.51	—	1.33
Surface Gravity (g)	1.00	2.04	2.53
Insolation (S⊕)	1.00	40.46	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Best measured mass	89.000 M⊕	Direct mass measurement (not derived).

Star Catalogue Identifiers

TIC

TIC 237929468

Gaia DR2

Gaia DR2 4679529734152652672

Gaia DR3

Gaia DR3 4679529738448820608

System

TOI-4940

Percentile among Neptune-like cohort

Radius 6.610 R⊕ · percentile 60 / cohort 574

Mass 89.000 M⊕ · percentile 90 / cohort 574

Orbital period 25.87 d · percentile 57 / cohort 524

Distance 345.66 pc · percentile 51 / cohort 572

ESI 0.261 · percentile 41 / cohort 574

Orbit & Habitability

Orbital Dynamics

Period

25.868 days

Semi-major axis

0.1650 AU

Eccentricity

—

Inclination

88.47 °

Year Length

A year here lasts approximately 25.87 Earth days (7.1% of a terrestrial year) at a mean orbital distance of 0.1650 AU.

Transit Fingerprint

Depth

0.261 %

Duration

4.291 h

Impact parameter b

0.817

Rp / R★

0.052100

Transit midpoint (BJD)

2,459,265.3032

Photometric dip

Transit produces a flux drop of 2,613 ppm lasting ≈ 4.29 h.

Extended Orbital Architecture

Planet / star radius ratio

0.052100

Impact parameter (b)

0.817

RV semi-amplitude (K)

8.500 m/s

Transit mid-time (BJD)

2,459,265.3032

Angular separation (arcsec)

0.47700

Eq. Temperature

643K

(370 °C)

Insolation (S⊕)

40.46

Earth = 1.00

Earth Similarity (ESI)

0.261

0 = alien, 1 = Earth-identical

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

Discovery Paper

Primary reference

Kendall et al. 2025

Instrument

TESS CCD Array

Publication

2025-12

Observation locale

Space

Discovery cohort

Planets confirmed in 2025 at Transiting Exoplanet Survey Satellite (TESS) (12 shown).

TOI-1266 d · Super-Earth TOI-2267 c · Rocky Terrestrial TOI-5799 c · Super-Earth TOI-5728 b · Super-Earth TOI-5716 b · Rocky Terrestrial TOI-7166 b · Sub-Neptune TOI-2267 b · Rocky Terrestrial TOI-2093 c · Sub-Neptune TOI-2267 d · Super-Earth TOI-5489 c · Super-Earth TOI-1743 b · Super-Earth TOI-4364 b · Sub-Neptune

Host System: TOI-4940

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,504 K — cooler than the Sun (5,778 K)

Estimated Age

9.80 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

1.163 R☉

Stellar Mass

1.012 M☉

Metallicity [Fe/H]

0.33

Extended Stellar Properties

Surface gravity (log g)

4.232 dex

Stellar density

0.843 g/cm³

Activity index (log R'HK)

-5.410

Metallicity ratio

[Fe/H]

Distance

345.66 parsec

Light-years 1,127.39 ly

V-band magnitude

12.45 mag

Voyager-speed travel 19,881,479 yr

Multi-band Host Photometry — 11 bands

Astrometric Data

Parallax

2.864 mas

Total Proper Motion

3.680 mas/yr

PM Right Ascension

0.78 mas/yr

PM Declination

-3.60 mas/yr

Galactic Cartesian (pc)

x = 0.244 · y = 0.394 · z = -0.886

Equatorial (J2000)

RA 58.25117° · Dec -62.40797°

Galactic ℓ, b

275.690° · -43.916°

Ecliptic λ, β

2.070° · -75.884°

HTM-20 index

1033800007