Confirmed Exoplanet Discovered 2025

TOI-3877 b

A gas giant orbiting the g-type yellow (sun-like) TOI-3877, located approximately 1,610.5 light-years from Earth.

Key parameters at a glance

  • A radius of 11.68 Earth radii
  • A mass of 99.80 Earth masses
  • Surface gravity around 0.73 g
  • An orbital period of 4.124 days
  • Semi-major axis 0.0529 AU
  • Equilibrium temperature 1,445 K (1172 °C)
  • Distance from Earth 1,610.46 light-years
  • Earth Similarity Index 0.083
  • Travel time at Voyager 1 speed 28,400,469 years

TOI-3877 b Planet Profile

Physical Specs

Radius
11.68 R⊕
Radius (Jupiter)
1.042 R♃
Mass
99.80 M⊕
Mass (Jupiter)
0.314 M♃
Density
0.34 g/cm³
Surface Gravity
0.73 g (Earth)

Classification

Planet Type

Gas Giant

ESI Score 0.083
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

#1568of 1771

top 88.5%

This planet

11.68R⊕

Gas Giant median

13.52R⊕

Nearest-size peers

Metric Earth TOI-3877 b Jupiter
Radius (R⊕)1.0011.6811.21
Mass (M⊕)1.0099.80317.83
Density (g/cm³)5.510.341.33
Surface Gravity (g)1.000.732.53
Insolation (S⊕)1.00729.000.037

Alternative Mass Estimates

Method Value Interpretation
Best measured mass 99.798 M⊕ Direct mass measurement (not derived).

Star Catalogue Identifiers

TIC

TIC 144310492

Gaia DR2

Gaia DR2 759209995840837248

Gaia DR3

Gaia DR3 759209995840837248

System

TOI-3877

Percentile among Gas Giant cohort

Radius 11.680 R⊕ · percentile 11 / cohort 1771
Mass 99.798 M⊕ · percentile 6 / cohort 1747
Orbital period 4.12 d · percentile 30 / cohort 1533
Distance 493.77 pc · percentile 74 / cohort 1759
ESI 0.083 · percentile 19 / cohort 1771

Orbit & Habitability

Orbital Dynamics

Period
4.124 days
Semi-major axis
0.0529 AU
Eccentricity
0.220
Inclination
83.97 °

Year Length

A year here lasts approximately 4.12 Earth days (1.1% of a terrestrial year) on a mildly elliptical path at a mean orbital distance of 0.0529 AU.

Transit Fingerprint

Depth

0.550 %

Duration

2.784 h

Impact parameter b

0.824

Transit midpoint (BJD)

2,459,753.9339

Photometric dip

Transit produces a flux drop of 5,500 ppm lasting ≈ 2.78 h.

Extended Orbital Architecture

Semi-major axis / stellar radius

7.850

Impact parameter (b)

0.824

RV semi-amplitude (K)

36.100 m/s

Transit mid-time (BJD)

2,459,753.9339

Angular separation (arcsec)

0.10700

Eq. Temperature

1,445K

(1172 °C)

Insolation (S⊕)

729.00

Earth = 1.00

Earth Similarity (ESI)

0.083

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

Yee et al. 2025

Instrument

TESS CCD Array

Publication

2025-07

Observation locale

Space

Host System: TOI-3877

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,731 K — cooler than the Sun (5,778 K)

Estimated Age

5.90 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

1.445 R☉

Stellar Mass

1.160 M☉

Metallicity [Fe/H]

0.27

Extended Stellar Properties

Surface gravity (log g)

4.181 dex

Stellar density

0.538 g/cm³

Metallicity ratio

[Fe/H]

Distance
493.77 parsec
Light-years 1,610.46 ly
V-band magnitude
12.22 mag
Voyager-speed travel 28,400,469 yr

Multi-band Host Photometry — 16 bands

8.515.415.38U13.33B12.22V12.36Gaia11.91TESS12.92Sloan g12.41Sloan r12.28Sloan i13.59Sloan z11.31J11.01H10.92K10.90W110.94W210.86W38.47W4

Astrometric Data

Parallax

1.997 mas

Total Proper Motion

20.354 mas/yr

PM Right Ascension

-20.00 mas/yr

PM Declination

-3.80 mas/yr

Galactic Cartesian (pc)

x = -0.818 · y = 0.137 · z = 0.559

Equatorial (J2000)

RA 170.45447° · Dec 33.99138°

Galactic ℓ, b

187.832° · 69.575°

Ecliptic λ, β

156.909° · 27.274°

HTM-20 index

-1130708694

Similar Worlds

Explore Related Categories