Confirmed Exoplanet Discovered 2026

TOI-5422 b

A neptune-like orbiting the g-type yellow (sun-like) TOI-5422, located approximately 1,129.0 light-years from Earth.

Key parameters at a glance

  • A radius of 9.10 Earth radii
  • A mass of 8,899.20 Earth masses
  • Surface gravity around 107.43 g
  • An orbital period of 5.377 days
  • Semi-major axis 0.0619 AU
  • Equilibrium temperature 1,369 K (1096 °C)
  • Distance from Earth 1,128.96 light-years
  • Earth Similarity Index 0.068
  • Travel time at Voyager 1 speed 19,909,202 years

TOI-5422 b Planet Profile

Physical Specs

Radius
9.10 R⊕
Radius (Jupiter)
0.812 R♃
Mass
8,899.20 M⊕
Mass (Jupiter)
28.000 M♃
Density
65.80 g/cm³
Surface Gravity
107.43 g (Earth)

Classification

Planet Type

Neptune-like

ESI Score 0.068
HZ Position Inner
Controversial No

Discovery

Year 2026
Method Transit
Facility Transiting Exoplanet Survey Satellite (TESS)
Telescope 0.1 m TESS Telescope

Size rank in cohort

Rank by radius

#79of 574

top 13.6%

This planet

9.10R⊕

Neptune-like median

6.39R⊕

Nearest-size peers

Metric Earth TOI-5422 b Jupiter
Radius (R⊕)1.009.1011.21
Mass (M⊕)1.008,899.20317.83
Density (g/cm³)5.5165.801.33
Surface Gravity (g)1.00107.432.53
Insolation (S⊕)1.00580.000.037

Alternative Mass Estimates

Method Value Interpretation
Best measured mass 8,899.195 M⊕ Direct mass measurement (not derived).
Minimum mass (M sin i) 8,867.413 M⊕ Lower bound from radial-velocity fitting.

Star Catalogue Identifiers

TIC

TIC 80611440

Gaia DR2

Gaia DR2 3429244825638569216

Gaia DR3

Gaia DR3 3429244825638569216

System

TOI-5422

Percentile among Neptune-like cohort

Radius 9.102 R⊕ · percentile 86 / cohort 574
Mass 8,899.195 M⊕ · percentile 100 / cohort 574
Orbital period 5.38 d · percentile 22 / cohort 524
Distance 346.14 pc · percentile 51 / cohort 572
ESI 0.068 · percentile 0 / cohort 574

Orbit & Habitability

Orbital Dynamics

Period
5.377 days
Semi-major axis
0.0619 AU
Eccentricity
0.094
Inclination
88.71 °

Year Length

A year here lasts approximately 5.38 Earth days (1.5% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0619 AU.

Transit Fingerprint

Depth

0.321 %

Duration

4.668 h

Impact parameter b

0.200

Rp / R★

0.056620

Transit midpoint (BJD)

2,459,961.6761

Photometric dip

Transit produces a flux drop of 3,206 ppm lasting ≈ 4.67 h.

Extended Orbital Architecture

Planet / star radius ratio

0.056620

Semi-major axis / stellar radius

9.080

Impact parameter (b)

0.200

RV semi-amplitude (K)

3,068.000 m/s

Transit mid-time (BJD)

2,459,961.6761

Long. of periastron (ω)

0.10°

Angular separation (arcsec)

0.17900

Eq. Temperature

1,369K

(1096 °C)

Insolation (S⊕)

580.00

Earth = 1.00

Earth Similarity (ESI)

0.068

0 = alien, 1 = Earth-identical

Inside the inner HZ boundary (too hot for liquid water) — the dayside is scorched.

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

Zhang et al. 2026

Instrument

TESS CCD Array

Publication

2026-02

Observation locale

Space

Host System: TOI-5422

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,820 K — hotter than the Sun (5,778 K)

Estimated Age

7.60 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

1.474 R☉

Stellar Mass

1.066 M☉

Metallicity [Fe/H]

-0.01

Extended Stellar Properties

Surface gravity (log g)

4.135 dex

Stellar density

0.479 g/cm³

Rotation period

10.80 days

Metallicity ratio

[Fe/H]

Distance
346.14 parsec
Light-years 1,128.96 ly
V-band magnitude
11.50 mag
Voyager-speed travel 19,909,202 yr

Multi-band Host Photometry — 11 bands

8.712.412.40B11.50V11.71Gaia11.24TESS10.58J10.25H10.16K10.14W110.17W210.21W38.67W4

Astrometric Data

Parallax

2.862 mas

Total Proper Motion

8.359 mas/yr

PM Right Ascension

8.36 mas/yr

PM Declination

-0.15 mas/yr

Galactic Cartesian (pc)

x = 0.050 · y = 0.900 · z = 0.432

Equatorial (J2000)

RA 86.84362° · Dec 25.62603°

Galactic ℓ, b

183.032° · -1.386°

Ecliptic λ, β

87.148° · 2.218°

HTM-20 index

-1060658068

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