Key parameters at a glance

A radius of 1.42 Earth radii
A mass of 2.59 Earth masses
Surface gravity around 1.29 g
An orbital period of 3.966 days
Semi-major axis 0.0359 AU
Equilibrium temperature 554 K (281 °C)
Distance from Earth 103.18 light-years
Earth Similarity Index 0.550
Travel time at Voyager 1 speed 1,819,593 years
Almost certainly tidally locked to its host star given the close orbit

TOI-4559 b Planet Profile

Physical Specs

Radius

1.42 R⊕

Radius (Jupiter)

0.126 R♃

Mass

2.59 M⊕

Mass (Jupiter)

0.008 M♃

Density

5.02 g/cm³

Surface Gravity

1.29 g (Earth)

Classification

Planet Type

Super-Earth

ESI Score 0.550

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

#900of 1176

top 76.4%

This planet

1.42R⊕

Super-Earth median

1.60R⊕

Nearest-size peers

Kepler-1038 c 1.42 R⊕ Kepler-1813 b 1.41 R⊕ TOI-1444 b 1.42 R⊕

Metric	Earth	TOI-4559 b	Jupiter
Radius (R⊕)	1.00	1.42	11.21
Mass (M⊕)	1.00	2.59	317.83
Density (g/cm³)	5.51	5.02	1.33
Surface Gravity (g)	1.00	1.29	2.53
Insolation (S⊕)	1.00	15.77	0.037

Star Catalogue Identifiers

TIC

TIC 271169413

Gaia DR2

Gaia DR2 6173120554255287808

Gaia DR3

Gaia DR3 6173120554255287808

System

TOI-4559

Percentile among Super-Earth cohort

Radius 1.415 R⊕ · percentile 23 / cohort 1176

Mass 2.590 M⊕ · percentile 23 / cohort 1176

Orbital period 3.97 d · percentile 31 / cohort 1164

Distance 31.64 pc · percentile 7 / cohort 1171

ESI 0.550 · percentile 77 / cohort 1176

Orbit & Habitability

Orbital Dynamics

Period

3.966 days

Semi-major axis

0.0359 AU

Eccentricity

—

Inclination

88.64 °

Year Length

A year here lasts approximately 3.97 Earth days (1.1% of a terrestrial year) at a mean orbital distance of 0.0359 AU.

Transit Fingerprint

Depth

0.120 %

Duration

1.390 h

Impact parameter b

0.470

Rp / R★

0.035000

Transit midpoint (BJD)

2,459,335.3447

Photometric dip

Transit produces a flux drop of 1,200 ppm lasting ≈ 1.39 h.

Extended Orbital Architecture

Planet / star radius ratio

0.035000

Semi-major axis / stellar radius

19.710

Impact parameter (b)

0.470

Transit mid-time (BJD)

2,459,335.3447

Angular separation (arcsec)

1.13000

Eq. Temperature

554K

(281 °C)

Insolation (S⊕)

15.77

Earth = 1.00

Earth Similarity (ESI)

0.550

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

Mistry et al. 2023

Instrument

TESS CCD Array

Publication

2023-11

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-4559

Spectral Class

M-type red dwarf

Effective Temperature

3,558 K — cooler than the Sun (5,778 K)

Estimated Age

7.00 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

0.374 R☉

Stellar Mass

0.392 M☉

Metallicity [Fe/H]

-0.09

Extended Stellar Properties

Surface gravity (log g)

4.884 dex

Stellar density

10.500 g/cm³

Metallicity ratio

[Fe/H]

Distance

31.64 parsec

Light-years 103.18 ly

V-band magnitude

13.12 mag

Voyager-speed travel 1,819,593 yr

Multi-band Host Photometry — 11 bands

Astrometric Data

Parallax

31.582 mas

Total Proper Motion

248.939 mas/yr

PM Right Ascension

37.15 mas/yr

PM Declination

-246.15 mas/yr

Galactic Cartesian (pc)

x = -0.742 · y = -0.446 · z = -0.500

Equatorial (J2000)

RA 211.01354° · Dec -30.01413°

Galactic ℓ, b

321.136° · 30.278°

Ecliptic λ, β

219.337° · -16.348°

HTM-20 index

2026800775