Confirmed Exoplanet Discovered 2025

TOI-2328 b

A neptune-like orbiting the g-type yellow (sun-like) TOI-2328, located approximately 756.0 light-years from Earth.

Key parameters at a glance

  • A radius of 9.98 Earth radii
  • A mass of 50.85 Earth masses
  • Surface gravity around 0.51 g
  • An orbital period of 17.102 days
  • Semi-major axis 0.1270 AU
  • Equilibrium temperature 842 K (569 °C)
  • Distance from Earth 755.97 light-years
  • Earth Similarity Index 0.152
  • Travel time at Voyager 1 speed 13,331,546 years

TOI-2328 b Planet Profile

Physical Specs

Radius
9.98 R⊕
Radius (Jupiter)
0.890 R♃
Mass
50.85 M⊕
Mass (Jupiter)
0.160 M♃
Density
0.29 g/cm³
Surface Gravity
0.51 g (Earth)

Classification

Planet Type

Neptune-like

ESI Score 0.152
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

#5of 574

top 0.7%

This planet

9.98R⊕

Neptune-like median

6.39R⊕

Nearest-size peers

Metric Earth TOI-2328 b Jupiter
Radius (R⊕)1.009.9811.21
Mass (M⊕)1.0050.85317.83
Density (g/cm³)5.510.291.33
Surface Gravity (g)1.000.512.53
Insolation (S⊕)1.0020.100.037

Alternative Mass Estimates

Method Value Interpretation
Best measured mass 50.853 M⊕ Direct mass measurement (not derived).

Star Catalogue Identifiers

TIC

TIC 394287035

Gaia DR2

Gaia DR2 4619939536821435904

Gaia DR3

Gaia DR3 4619939536821435904

System

TOI-2328

Percentile among Neptune-like cohort

Radius 9.976 R⊕ · percentile 99 / cohort 574
Mass 50.853 M⊕ · percentile 70 / cohort 574
Orbital period 17.10 d · percentile 48 / cohort 524
Distance 231.78 pc · percentile 42 / cohort 572
ESI 0.152 · percentile 14 / cohort 574

Orbit & Habitability

Orbital Dynamics

Period
17.102 days
Semi-major axis
0.1270 AU
Eccentricity
0.057
Inclination
88.66 °

Year Length

A year here lasts approximately 17.10 Earth days (4.7% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.1270 AU.

Transit Fingerprint

Depth

1.143 %

Duration

3.357 h

Impact parameter b

0.688

Rp / R★

0.102000

Transit midpoint (BJD)

2,458,330.4894

Photometric dip

Transit produces a flux drop of 11,430 ppm lasting ≈ 3.36 h.

Extended Orbital Architecture

Planet / star radius ratio

0.102000

Impact parameter (b)

0.688

RV semi-amplitude (K)

13.290 m/s

Transit mid-time (BJD)

2,458,330.4894

Long. of periastron (ω)

148.70°

Angular separation (arcsec)

0.54800

Eq. Temperature

842K

(569 °C)

Insolation (S⊕)

20.10

Earth = 1.00

Earth Similarity (ESI)

0.152

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.

Radial velocity

Stellar wobble has been measured spectroscopically.

Discovery Paper

Primary reference

Tala Pinto et al. 2025

Instrument

TESS CCD Array

Publication

2025-02

Observation locale

Space

Host System: TOI-2328

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,525 K — cooler than the Sun (5,778 K)

Estimated Age

4.00 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

0.900 R☉

Stellar Mass

0.950 M☉

Metallicity [Fe/H]

0.09

Extended Stellar Properties

Surface gravity (log g)

4.505 dex

Stellar density

1.806 g/cm³

Rotational v·sin i

2.61 km/s

Activity index (log R'HK)

-5.088

Metallicity ratio

[Fe/H]

Distance
231.78 parsec
Light-years 755.97 ly
V-band magnitude
12.33 mag
Voyager-speed travel 13,331,546 yr

Multi-band Host Photometry — 11 bands

9.313.413.37B12.33V12.11Gaia11.58TESS10.84J10.46H10.40K10.32W110.35W210.23W39.29W4

Astrometric Data

Parallax

4.286 mas

Total Proper Motion

31.848 mas/yr

PM Right Ascension

31.80 mas/yr

PM Declination

-1.68 mas/yr

Galactic Cartesian (pc)

x = 0.129 · y = 0.080 · z = -0.988

Equatorial (J2000)

RA 31.69074° · Dec -81.24738°

Galactic ℓ, b

299.479° · -35.370°

Ecliptic λ, β

292.038° · -69.817°

HTM-20 index

1988121424

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