Confirmed Exoplanet Discovered 2024

TOI-6255 b

A rocky terrestrial orbiting the m-type red dwarf TOI-6255, located approximately 66.3 light-years from Earth.

Key parameters at a glance

  • A radius of 1.08 Earth radii
  • A mass of 1.44 Earth masses
  • Surface gravity around 1.24 g
  • An orbital period of 0.238 days
  • Equilibrium temperature 1,256 K (983 °C)
  • Distance from Earth 66.26 light-years
  • Earth Similarity Index 0.243
  • Travel time at Voyager 1 speed 1,168,568 years
  • Almost certainly tidally locked to its host star given the close orbit

TOI-6255 b Planet Profile

Physical Specs

Radius
1.08 R⊕
Radius (Jupiter)
0.096 R♃
Mass
1.44 M⊕
Mass (Jupiter)
0.005 M♃
Density
6.30 g/cm³
Surface Gravity
1.24 g (Earth)

Classification

Planet Type

Rocky Terrestrial

ESI Score 0.243
HZ Position Inner
Controversial No

Discovery

Year 2024
Method Transit
Facility Transiting Exoplanet Survey Satellite (TESS)
Telescope 0.1 m TESS Telescope

Size rank in cohort

Rank by radius

#256of 570

top 44.7%

This planet

1.08R⊕

Rocky Terrestrial median

1.01R⊕

Nearest-size peers

Metric Earth TOI-6255 b Jupiter
Radius (R⊕)1.001.0811.21
Mass (M⊕)1.001.44317.83
Density (g/cm³)5.516.301.33
Surface Gravity (g)1.001.242.53
Insolation (S⊕)1.00588.990.037

Alternative Mass Estimates

Method Value Interpretation
Best measured mass 1.440 M⊕ Direct mass measurement (not derived).

Star Catalogue Identifiers

TIC

TIC 261135533

Gaia DR2

Gaia DR2 1956328333130770048

Gaia DR3

Gaia DR3 1956328333130770048

System

TOI-6255

Percentile among Rocky Terrestrial cohort

Radius 1.079 R⊕ · percentile 55 / cohort 570
Mass 1.440 M⊕ · percentile 59 / cohort 570
Orbital period 0.24 d · percentile 0 / cohort 567
Distance 20.32 pc · percentile 10 / cohort 566
ESI 0.243 · percentile 24 / cohort 570

Orbit & Habitability

Orbital Dynamics

Period
0.238 days
Semi-major axis
AU
Eccentricity
0.000
Inclination
74.40 °

Year Length

A year here lasts roughly 5.7 hours long on a nearly circular orbit.

Transit Fingerprint

Depth

0.049 %

Duration

0.476 h

Impact parameter b

0.840

Rp / R★

0.026700

Transit midpoint (BJD)

2,458,738.7125

Photometric dip

Transit produces a flux drop of 494 ppm lasting ≈ 0.48 h.

Extended Orbital Architecture

Planet / star radius ratio

0.026700

Semi-major axis / stellar radius

3.100

Impact parameter (b)

0.840

RV semi-amplitude (K)

2.980 m/s

Transit mid-time (BJD)

2,458,738.7125

Eq. Temperature

1,256K

(983 °C)

Insolation (S⊕)

588.99

Earth = 1.00

Earth Similarity (ESI)

0.243

0 = alien, 1 = Earth-identical

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

Dai et al. 2024

Instrument

TESS CCD Array

Publication

2024-09

Observation locale

Space

Host System: TOI-6255

Spectral Class

M-type red dwarf

Effective Temperature

3,421 K — cooler than the Sun (5,778 K)

Estimated Age

Stellar Radius

0.370 R☉

Stellar Mass

0.353 M☉

Metallicity [Fe/H]

-0.14

Extended Stellar Properties

Surface gravity (log g)

4.850 dex

Stellar density

9.800 g/cm³

Metallicity ratio

[Fe/H]

Distance
20.32 parsec
Light-years 66.26 ly
V-band magnitude
12.75 mag
Voyager-speed travel 1,168,568 yr

Multi-band Host Photometry — 7 bands

8.114.514.53B12.75V11.63Gaia10.45TESS8.91J8.31H8.07K

Astrometric Data

Parallax

49.192 mas

Total Proper Motion

464.103 mas/yr

PM Right Ascension

69.19 mas/yr

PM Declination

-458.92 mas/yr

Galactic Cartesian (pc)

x = 0.680 · y = -0.369 · z = 0.633

Equatorial (J2000)

RA 331.50316° · Dec 39.29883°

Galactic ℓ, b

91.252° · -13.189°

Ecliptic λ, β

352.722° · 46.716°

HTM-20 index

-532466254

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