Confirmed Exoplanet Discovered 2025

TOI-2345 c

A sub-neptune orbiting the k-type orange TOI-2345, located approximately 266.3 light-years from Earth.

Key parameters at a glance

  • A radius of 2.45 Earth radii
  • A mass of 7.27 Earth masses
  • Surface gravity around 1.21 g
  • An orbital period of 21.064 days
  • Semi-major axis 0.1257 AU
  • Equilibrium temperature 544 K (271 °C)
  • Distance from Earth 266.32 light-years
  • Earth Similarity Index 0.470
  • Travel time at Voyager 1 speed 4,696,548 years
  • Almost certainly tidally locked to its host star given the close orbit

1 sibling around TOI-2345

TOI-2345 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-2345 b Super-Earth 1.50 3.49 1.053 1,478 2025
TOI-2345 c this Sub-Neptune 2.45 7.27 21.064 544 2025

TOI-2345 c Planet Profile

Physical Specs

Radius
2.45 R⊕
Radius (Jupiter)
0.219 R♃
Mass
7.27 M⊕
Mass (Jupiter)
0.023 M♃
Density
2.71 g/cm³
Surface Gravity
1.21 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.470
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

#1259of 1978

top 63.6%

This planet

2.45R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

Metric Earth TOI-2345 c Jupiter
Radius (R⊕)1.002.4511.21
Mass (M⊕)1.007.27317.83
Density (g/cm³)5.512.711.33
Surface Gravity (g)1.001.212.53
Insolation (S⊕)1.0014.570.037

Alternative Mass Estimates

Method Value Interpretation
Best measured mass 7.270 M⊕ Direct mass measurement (not derived).

Star Catalogue Identifiers

TIC

TIC 91555165

Gaia DR2

Gaia DR2 5049575943053753088

Gaia DR3

Gaia DR3 5049575943053753088

System

TOI-2345

Percentile among Sub-Neptune cohort

Radius 2.451 R⊕ · percentile 36 / cohort 1978
Mass 7.270 M⊕ · percentile 44 / cohort 1978
Orbital period 21.06 d · percentile 64 / cohort 1946
Distance 81.65 pc · percentile 18 / cohort 1975
ESI 0.470 · percentile 66 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period
21.064 days
Semi-major axis
0.1257 AU
Eccentricity
Inclination
89.91 °

Year Length

A year here lasts approximately 21.06 Earth days (5.8% of a terrestrial year) at a mean orbital distance of 0.1257 AU.

Transit Fingerprint

Depth

0.096 %

Duration

4.613 h

Impact parameter b

0.056

Rp / R★

0.030820

Transit midpoint (BJD)

2,459,120.3007

Photometric dip

Transit produces a flux drop of 962 ppm lasting ≈ 4.61 h.

Extended Orbital Architecture

Planet / star radius ratio

0.030820

Semi-major axis / stellar radius

37.070

Impact parameter (b)

0.056

RV semi-amplitude (K)

2.080 m/s

Transit mid-time (BJD)

2,459,120.3007

Angular separation (arcsec)

1.54000

Eq. Temperature

544K

(271 °C)

Insolation (S⊕)

14.57

Earth = 1.00

Earth Similarity (ESI)

0.470

0 = alien, 1 = Earth-identical

Inside the inner HZ boundary (too hot for liquid water) — the surface is too hot to retain surface water. Close-orbiting tidally-locked around a cool host.

Detection Signatures

Transit photometry

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

Radial velocity

Stellar wobble has been measured spectroscopically.

Discovery Paper

Primary reference

Eschen et al. 2025

Instrument

TESS CCD Array

Publication

2025-10

Observation locale

Space

Host System: TOI-2345

Spectral Class

K-type orange

Effective Temperature

4,687 K — cooler than the Sun (5,778 K)

Estimated Age

6.30 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

0.729 R☉

Stellar Mass

0.727 M☉

Metallicity [Fe/H]

-0.10

Extended Stellar Properties

Surface gravity (log g)

4.570 dex

Stellar density

2.650 g/cm³

Systemic radial velocity

58.14 km/s

Rotational v·sin i

2.30 km/s

Metallicity ratio

[Fe/H]

Distance
81.65 parsec
Light-years 266.32 ly
V-band magnitude
11.48 mag
Voyager-speed travel 4,696,548 yr

Multi-band Host Photometry — 11 bands

8.712.412.40B11.48V11.03Gaia10.38TESS9.51J8.94H8.85K8.76W18.84W28.77W38.66W4

Astrometric Data

Parallax

12.218 mas

Total Proper Motion

227.719 mas/yr

PM Right Ascension

202.40 mas/yr

PM Declination

-104.35 mas/yr

Galactic Cartesian (pc)

x = 0.591 · y = 0.568 · z = -0.573

Equatorial (J2000)

RA 43.88479° · Dec -34.97797°

Galactic ℓ, b

237.158° · -62.413°

Ecliptic λ, β

26.392° · -48.755°

HTM-20 index

-392653523

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