Key parameters at a glance

A radius of 2.81 Earth radii
A mass of 9.83 Earth masses
Surface gravity around 1.24 g
An orbital period of 1.239 days
Semi-major axis 0.0180 AU
Equilibrium temperature 934 K (661 °C)
Distance from Earth 281.07 light-years
Earth Similarity Index 0.263
Travel time at Voyager 1 speed 4,956,632 years
Almost certainly tidally locked to its host star given the close orbit

1 sibling around TOI-756

TOI-756 b 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-756 b this	Sub-Neptune	2.81	9.83	1.239	934	2025
TOI-756 c	Gas Giant	13.00	1,287.21	149.400	194	2025

TOI-756 b Planet Profile

Physical Specs

Radius

2.81 R⊕

Radius (Jupiter)

0.251 R♃

Mass

9.83 M⊕

Mass (Jupiter)

0.031 M♃

Density

2.42 g/cm³

Surface Gravity

1.24 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.263

HZ Position Inner

Controversial No

Discovery

Year 2025

Method Transit

Facility Transiting Exoplanet Survey Satellite (TESS)

Telescope 0.1 m TESS Telescope

Size rank in cohort

Rank by radius

#732of 1978

top 37.0%

This planet

2.81R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

Kepler-752 b 2.81 R⊕ Kepler-1234 b 2.81 R⊕ Kepler-892 b 2.81 R⊕

Metric	Earth	TOI-756 b	Jupiter
Radius (R⊕)	1.00	2.81	11.21
Mass (M⊕)	1.00	9.83	317.83
Density (g/cm³)	5.51	2.42	1.33
Surface Gravity (g)	1.00	1.24	2.53
Insolation (S⊕)	1.00	127.00	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Best measured mass	9.830 M⊕	Direct mass measurement (not derived).

Star Catalogue Identifiers

TIC

TIC 73649615

Gaia DR2

Gaia DR2 6129327525817451648

Gaia DR3

Gaia DR3 6129327525817451648

System

TOI-756

Percentile among Sub-Neptune cohort

Radius 2.810 R⊕ · percentile 63 / cohort 1978

Mass 9.830 M⊕ · percentile 72 / cohort 1978

Orbital period 1.24 d · percentile 0 / cohort 1946

Distance 86.18 pc · percentile 19 / cohort 1975

ESI 0.263 · percentile 19 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period

1.239 days

Semi-major axis

0.0180 AU

Eccentricity

0.000

Inclination

85.53 °

Year Length

A year here lasts approximately 1.24 Earth days (0.3% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0180 AU.

Transit Fingerprint

Depth

0.292 %

Duration

1.100 h

Impact parameter b

0.589

Rp / R★

0.051130

Transit midpoint (BJD)

2,458,570.6523

Photometric dip

Transit produces a flux drop of 2,917 ppm lasting ≈ 1.10 h.

Extended Orbital Architecture

Planet / star radius ratio

0.051130

Impact parameter (b)

0.589

RV semi-amplitude (K)

9.200 m/s

Transit mid-time (BJD)

2,458,570.6523

Long. of periastron (ω)

90.00°

Angular separation (arcsec)

0.20900

Eq. Temperature

934K

(661 °C)

Insolation (S⊕)

127.00

Earth = 1.00

Earth Similarity (ESI)

0.263

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

Parc et al. 2025

Instrument

TESS CCD Array

Publication

2025-10

Observation locale

Space

Discovery cohort

Planets confirmed in 2025 at Transiting Exoplanet Survey Satellite (TESS) (12 shown).

TOI-1266 d · Super-Earth TOI-2267 c · Rocky Terrestrial TOI-5799 c · Super-Earth TOI-5728 b · Super-Earth TOI-5716 b · Rocky Terrestrial TOI-7166 b · Sub-Neptune TOI-2267 b · Rocky Terrestrial TOI-2093 c · Sub-Neptune TOI-2267 d · Super-Earth TOI-5489 c · Super-Earth TOI-1743 b · Super-Earth TOI-4364 b · Sub-Neptune

Host System: TOI-756

Spectral Class

M-type red dwarf

Effective Temperature

3,657 K — cooler than the Sun (5,778 K)

Estimated Age

3.20 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

0.505 R☉

Stellar Mass

0.505 M☉

Metallicity [Fe/H]

0.20

Extended Stellar Properties

Surface gravity (log g)

4.735 dex

Stellar density

5.520 g/cm³

Systemic radial velocity

15.36 km/s

Metallicity ratio

[Fe/H]

Distance

86.18 parsec

Light-years 281.07 ly

V-band magnitude

14.61 mag

Voyager-speed travel 4,956,632 yr

Multi-band Host Photometry — 11 bands

Astrometric Data

Parallax

11.576 mas

Total Proper Motion

218.335 mas/yr

PM Right Ascension

-216.37 mas/yr

PM Declination

29.21 mas/yr

Galactic Cartesian (pc)

x = -0.686 · y = -0.147 · z = -0.713

Equatorial (J2000)

RA 192.10374° · Dec -45.47047°

Galactic ℓ, b

302.377° · 17.398°

Ecliptic λ, β

211.392° · -36.553°

HTM-20 index

-650066536