Confirmed Exoplanet Discovered 2024

TOI-1408 c

A sub-neptune orbiting the f-type yellow-white TOI-1408, located approximately 454.9 light-years from Earth.

Key parameters at a glance

  • A radius of 2.22 Earth radii
  • A mass of 7.60 Earth masses
  • Surface gravity around 1.54 g
  • An orbital period of 2.166 days
  • Semi-major axis 0.0359 AU
  • Equilibrium temperature 1,864 K (1591 °C)
  • Distance from Earth 454.94 light-years
  • Earth Similarity Index 0.132
  • Travel time at Voyager 1 speed 8,022,786 years

1 sibling around TOI-1408

TOI-1408 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-1408 c this Sub-Neptune 2.22 7.60 2.166 1,864 2024
TOI-1408 b Gas Giant 25.00 593.00 4.426 1,293 2023

TOI-1408 c Planet Profile

Physical Specs

Radius
2.22 R⊕
Radius (Jupiter)
0.198 R♃
Mass
7.60 M⊕
Mass (Jupiter)
0.024 M♃
Density
3.80 g/cm³
Surface Gravity
1.54 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.132
HZ Position Inner
Controversial No

Discovery

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

Size rank in cohort

Rank by radius

#1642of 1978

top 83.0%

This planet

2.22R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

Metric Earth TOI-1408 c Jupiter
Radius (R⊕)1.002.2211.21
Mass (M⊕)1.007.60317.83
Density (g/cm³)5.513.801.33
Surface Gravity (g)1.001.542.53
Insolation (S⊕)1.002,005.350.037

Alternative Mass Estimates

Method Value Interpretation
Best measured mass 7.600 M⊕ Direct mass measurement (not derived).

Star Catalogue Identifiers

TIC

TIC 364186197

Gaia DR2

Gaia DR2 2275130045974715904

Gaia DR3

Gaia DR3 2275130045974715904

System

TOI-1408

Percentile among Sub-Neptune cohort

Radius 2.220 R⊕ · percentile 17 / cohort 1978
Mass 7.600 M⊕ · percentile 49 / cohort 1978
Orbital period 2.17 d · percentile 2 / cohort 1946
Distance 139.48 pc · percentile 24 / cohort 1975
ESI 0.132 · percentile 1 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period
2.166 days
Semi-major axis
0.0359 AU
Eccentricity
0.135
Inclination
82.60 °

Year Length

A year here lasts approximately 2.17 Earth days (0.6% of a terrestrial year) on a mildly elliptical path at a mean orbital distance of 0.0359 AU.

Transit Fingerprint

Depth

0.009 %

Duration

2.670 h

Rp / R★

0.013400

Transit midpoint (BJD)

2,458,739.8470

Photometric dip

Transit produces a flux drop of 87 ppm lasting ≈ 2.67 h.

Extended Orbital Architecture

Planet / star radius ratio

0.013400

Semi-major axis / stellar radius

5.040

Transit mid-time (BJD)

2,458,739.8470

Long. of periastron (ω)

286.30°

Angular separation (arcsec)

0.25700

Eq. Temperature

1,864K

(1591 °C)

Insolation (S⊕)

2,005.35

Earth = 1.00

Earth Similarity (ESI)

0.132

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.

Transit timing variations

Gravitational interactions from neighbours have been detected.

Discovery Paper

Primary reference

Korth et al. 2024

Instrument

TESS CCD Array

Publication

2024-07

Observation locale

Space

Host System: TOI-1408

Spectral Class

F-type yellow-white

Effective Temperature

6,117 K — hotter than the Sun (5,778 K)

Estimated Age

2.70 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

1.530 R☉

Stellar Mass

1.312 M☉

Metallicity [Fe/H]

0.25

Extended Stellar Properties

Surface gravity (log g)

4.100 dex

Stellar density

0.520 g/cm³

Rotational v·sin i

9.80 km/s

Rotation period

7.91 days

Metallicity ratio

[Fe/H]

Distance
139.48 parsec
Light-years 454.94 ly
V-band magnitude
9.27 mag
Voyager-speed travel 8,022,786 yr

Multi-band Host Photometry — 11 bands

8.09.89.84B9.27V9.19Gaia8.82TESS8.37J8.14H8.08K8.03W18.07W28.05W38.04W4

Astrometric Data

Parallax

7.140 mas

Total Proper Motion

31.089 mas/yr

PM Right Ascension

11.81 mas/yr

PM Declination

28.76 mas/yr

Galactic Cartesian (pc)

x = 0.206 · y = -0.217 · z = 0.954

Equatorial (J2000)

RA 313.51105° · Dec 72.58065°

Galactic ℓ, b

107.273° · 17.412°

Ecliptic λ, β

41.181° · 74.105°

HTM-20 index

127581591

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