Key parameters at a glance

A radius of 0.99 Earth radii
A mass of 2.20 Earth masses
Surface gravity around 2.24 g
An orbital period of 2.595 days
Semi-major axis 0.0243 AU
Equilibrium temperature 488 K (215 °C)
Distance from Earth 60.41 light-years
Earth Similarity Index 0.561
Travel time at Voyager 1 speed 1,065,376 years
Almost certainly tidally locked to its host star given the close orbit

TOI-5388.01 Planet Profile

Physical Specs

Radius

0.99 R⊕

Radius (Jupiter)

0.088 R♃

Mass

2.20 M⊕

Mass (Jupiter)

0.007 M♃

Density

11.90 g/cm³

Surface Gravity

2.24 g (Earth)

Classification

Planet Type

Rocky Terrestrial

ESI Score 0.561

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

#346of 570

top 60.5%

This planet

0.99R⊕

Rocky Terrestrial median

1.01R⊕

Nearest-size peers

EPIC 220492298 b 0.99 R⊕ Kepler-381 b 0.99 R⊕ Kepler-969 c 0.99 R⊕

Metric	Earth	TOI-5388.01	Jupiter
Radius (R⊕)	1.00	0.99	11.21
Mass (M⊕)	1.00	2.20	317.83
Density (g/cm³)	5.51	11.90	1.33
Surface Gravity (g)	1.00	2.24	2.53
Insolation (S⊕)	1.00	3.30	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Best measured mass	2.200 M⊕	Direct mass measurement (not derived).

Star Catalogue Identifiers

TIC

TIC 407591297

Gaia DR2

Gaia DR2 753585104807022080

Gaia DR3

Gaia DR3 753585104807022080

System

TOI-5388

Percentile among Rocky Terrestrial cohort

Radius 0.990 R⊕ · percentile 38 / cohort 570

Mass 2.200 M⊕ · percentile 91 / cohort 570

Orbital period 2.59 d · percentile 30 / cohort 567

Distance 18.52 pc · percentile 9 / cohort 566

ESI 0.561 · percentile 75 / cohort 570

Orbit & Habitability

Orbital Dynamics

Period

2.595 days

Semi-major axis

0.0243 AU

Eccentricity

—

Inclination

88.80 °

Year Length

A year here lasts approximately 2.59 Earth days (0.7% of a terrestrial year) at a mean orbital distance of 0.0243 AU.

Transit Fingerprint

Depth

0.107 %

Duration

0.313 h

Impact parameter b

0.430

Rp / R★

0.030500

Transit midpoint (BJD)

2,459,348.0782

Photometric dip

Transit produces a flux drop of 1,070 ppm lasting ≈ 0.31 h.

Extended Orbital Architecture

Planet / star radius ratio

0.030500

Semi-major axis / stellar radius

20.500

Impact parameter (b)

0.430

RV semi-amplitude (K)

0.440 m/s

Transit mid-time (BJD)

2,459,348.0782

Angular separation (arcsec)

1.31000

Eq. Temperature

488K

(215 °C)

Insolation (S⊕)

3.30

Earth = 1.00

Earth Similarity (ESI)

0.561

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.

Discovery Paper

Primary reference

Hord et al. 2024

Instrument

TESS CCD Array

Publication

2024-05

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-5388

Spectral Class

M-type red dwarf

Effective Temperature

3,440 K — cooler than the Sun (5,778 K)

Estimated Age

—

Stellar Radius

0.300 R☉

Stellar Mass

0.292 M☉

Metallicity [Fe/H]

-0.36

Extended Stellar Properties

Surface gravity (log g)

4.990 dex

Stellar density

17.000 g/cm³

Rotational v·sin i

2.00 km/s

Metallicity ratio

[Fe/H]

Distance

18.52 parsec

Light-years 60.41 ly

V-band magnitude

12.73 mag

Voyager-speed travel 1,065,376 yr

Multi-band Host Photometry — 11 bands

Astrometric Data

Parallax

53.959 mas

Total Proper Motion

234.075 mas/yr

PM Right Ascension

192.54 mas/yr

PM Declination

133.12 mas/yr

Galactic Cartesian (pc)

x = -0.720 · y = 0.380 · z = 0.581

Equatorial (J2000)

RA 152.17652° · Dec 35.54756°

Galactic ℓ, b

188.938° · 54.511°

Ecliptic λ, β

141.141° · 22.479°

HTM-20 index

-1031576575