Key parameters at a glance

A radius of 1.32 Earth radii
A mass of 2.08 Earth masses
Surface gravity around 1.19 g
An orbital period of 3.307 days
Semi-major axis 0.0322 AU
Equilibrium temperature 584 K (311 °C)
Distance from Earth 101.30 light-years
Earth Similarity Index 0.529
Travel time at Voyager 1 speed 1,786,480 years
Almost certainly tidally locked to its host star given the close orbit

1 sibling around TOI-406

TOI-406 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-406 c this	Super-Earth	1.32	2.08	3.307	584	2024
TOI-406.01	Sub-Neptune	2.08	6.57	13.176	368	2024

TOI-406 c Planet Profile

Physical Specs

Radius

1.32 R⊕

Radius (Jupiter)

0.118 R♃

Mass

2.08 M⊕

Mass (Jupiter)

0.007 M♃

Density

4.90 g/cm³

Surface Gravity

1.19 g (Earth)

Classification

Planet Type

Super-Earth

ESI Score 0.529

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

#1049of 1176

top 89.1%

This planet

1.32R⊕

Super-Earth median

1.60R⊕

Nearest-size peers

Kepler-1506 b 1.32 R⊕ Kepler-383 b 1.32 R⊕ Kepler-157 b 1.32 R⊕

Metric	Earth	TOI-406 c	Jupiter
Radius (R⊕)	1.00	1.32	11.21
Mass (M⊕)	1.00	2.08	317.83
Density (g/cm³)	5.51	4.90	1.33
Surface Gravity (g)	1.00	1.19	2.53
Insolation (S⊕)	1.00	19.00	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Best measured mass	2.080 M⊕	Direct mass measurement (not derived).

Star Catalogue Identifiers

TIC

TIC 153065527

Gaia DR2

Gaia DR2 4851053999056603904

Gaia DR3

Gaia DR3 4851053999056603904

System

TOI-406

Percentile among Super-Earth cohort

Radius 1.320 R⊕ · percentile 9 / cohort 1176

Mass 2.080 M⊕ · percentile 2 / cohort 1176

Orbital period 3.31 d · percentile 25 / cohort 1164

Distance 31.06 pc · percentile 7 / cohort 1171

ESI 0.529 · percentile 75 / cohort 1176

Orbit & Habitability

Orbital Dynamics

Period

3.307 days

Semi-major axis

0.0322 AU

Eccentricity

0.032

Inclination

87.60 °

Year Length

A year here lasts approximately 3.31 Earth days (0.9% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0322 AU.

Transit Fingerprint

Depth

0.106 %

Duration

1.050 h

Impact parameter b

0.730

Rp / R★

0.029700

Transit midpoint (BJD)

2,458,385.3880

Photometric dip

Transit produces a flux drop of 1,061 ppm lasting ≈ 1.05 h.

Extended Orbital Architecture

Planet / star radius ratio

0.029700

Semi-major axis / stellar radius

17.600

Impact parameter (b)

0.730

RV semi-amplitude (K)

1.630 m/s

Transit mid-time (BJD)

2,458,385.3880

Long. of periastron (ω)

-6.00°

Angular separation (arcsec)

1.04000

Eq. Temperature

584K

(311 °C)

Insolation (S⊕)

19.00

Earth = 1.00

Earth Similarity (ESI)

0.529

0 = alien, 1 = Earth-identical

Inside the inner HZ boundary (too hot for liquid water) — the surface is too hot to retain surface water. 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

Lacedelli et al. 2024

Instrument

TESS CCD Array

Publication

2024-09

Observation locale

Space

Discovery cohort

Planets confirmed in 2024 at Transiting Exoplanet Survey Satellite (TESS) (12 shown).

Gliese 12 b · Rocky Terrestrial TOI-6002 b · Super-Earth TOI-5713 b · Super-Earth TOI-4336 A b · Sub-Neptune TOI-406.01 · Sub-Neptune TOI-1224 c · Sub-Neptune LHS 1678 d · Rocky Terrestrial TOI-2088 b · Sub-Neptune TOI-2120 b · Sub-Neptune TOI-1806.01 · Sub-Neptune TOI-4633 c · Sub-Neptune TOI-260 b · Super-Earth

Host System: TOI-406

Spectral Class

M-type red dwarf

Effective Temperature

3,392 K — cooler than the Sun (5,778 K)

Estimated Age

—

Stellar Radius

0.410 R☉

Stellar Mass

0.408 M☉

Metallicity [Fe/H]

-0.02

Extended Stellar Properties

Surface gravity (log g)

4.690 dex

Stellar density

9.446 g/cm³

Systemic radial velocity

14.48 km/s

Rotation period

29.20 days

Activity index (log R'HK)

-5.167

Metallicity ratio

[M/H]

Distance

31.06 parsec

Light-years 101.30 ly

V-band magnitude

13.77 mag

Voyager-speed travel 1,786,480 yr

Multi-band Host Photometry — 7 bands

Astrometric Data

Parallax

32.167 mas

Total Proper Motion

414.925 mas/yr

PM Right Ascension

41.67 mas/yr

PM Declination

-412.83 mas/yr

Galactic Cartesian (pc)

x = 0.483 · y = 0.561 · z = -0.672

Equatorial (J2000)

RA 49.26264° · Dec -42.24415°

Galactic ℓ, b

249.563° · -56.807°

Ecliptic λ, β

27.096° · -57.133°

HTM-20 index

-938313135