Confirmed Exoplanet Discovered 2024

TOI-757 b

A sub-neptune orbiting the k-type orange TOI-757, located approximately 196.8 light-years from Earth.

Key parameters at a glance

  • A radius of 2.50 Earth radii
  • A mass of 10.50 Earth masses
  • Surface gravity around 1.68 g
  • An orbital period of 17.468 days
  • Semi-major axis 0.1220 AU
  • Equilibrium temperature 641 K (368 °C)
  • Distance from Earth 196.81 light-years
  • Earth Similarity Index 0.413
  • Travel time at Voyager 1 speed 3,470,716 years
  • Almost certainly tidally locked to its host star given the close orbit

TOI-757 b Planet Profile

Physical Specs

Radius
2.50 R⊕
Radius (Jupiter)
0.223 R♃
Mass
10.50 M⊕
Mass (Jupiter)
0.033 M♃
Density
3.60 g/cm³
Surface Gravity
1.68 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.413
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

#1168of 1978

top 59.0%

This planet

2.50R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

Metric Earth TOI-757 b Jupiter
Radius (R⊕)1.002.5011.21
Mass (M⊕)1.0010.50317.83
Density (g/cm³)5.513.601.33
Surface Gravity (g)1.001.682.53
Insolation (S⊕)1.0024.360.037

Alternative Mass Estimates

Method Value Interpretation
Best measured mass 10.500 M⊕ Direct mass measurement (not derived).

Star Catalogue Identifiers

TIC

TIC 130924120

Gaia DR2

Gaia DR2 6157753406084087168

Gaia DR3

Gaia DR3 6157753406084087168

System

TOI-757

Percentile among Sub-Neptune cohort

Radius 2.500 R⊕ · percentile 40 / cohort 1978
Mass 10.500 M⊕ · percentile 76 / cohort 1978
Orbital period 17.47 d · percentile 57 / cohort 1946
Distance 60.34 pc · percentile 13 / cohort 1975
ESI 0.413 · percentile 55 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period
17.468 days
Semi-major axis
0.1220 AU
Eccentricity
0.390
Inclination
89.50 °

Year Length

A year here lasts approximately 17.47 Earth days (4.8% of a terrestrial year) on a highly eccentric trajectory at a mean orbital distance of 0.1220 AU.

Transit Fingerprint

Depth

0.093 %

Duration

3.720 h

Impact parameter b

0.300

Rp / R★

0.029900

Transit midpoint (BJD)

2,459,305.5322

Photometric dip

Transit produces a flux drop of 926 ppm lasting ≈ 3.72 h.

Extended Orbital Architecture

Planet / star radius ratio

0.029900

Impact parameter (b)

0.300

RV semi-amplitude (K)

3.300 m/s

Transit mid-time (BJD)

2,459,305.5322

Long. of periastron (ω)

-36.00°

Angular separation (arcsec)

2.02000

Eq. Temperature

641K

(368 °C)

Insolation (S⊕)

24.36

Earth = 1.00

Earth Similarity (ESI)

0.413

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

Alqasim et al. 2024

Instrument

TESS CCD Array

Publication

2024-07

Observation locale

Space

Host System: TOI-757

Spectral Class

K-type orange

Effective Temperature

5,278 K — cooler than the Sun (5,778 K)

Estimated Age

7.50 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

0.780 R☉

Stellar Mass

0.800 M☉

Metallicity [Fe/H]

-0.27

Extended Stellar Properties

Surface gravity (log g)

4.500 dex

Stellar density

2.400 g/cm³

Rotational v·sin i

2.40 km/s

Metallicity ratio

[Fe/H]

Distance
60.34 parsec
Light-years 196.81 ly
V-band magnitude
9.74 mag
Voyager-speed travel 3,470,716 yr

Multi-band Host Photometry — 11 bands

7.710.610.56B9.74V9.55Gaia9.05TESS8.35J7.98H7.87K7.81W17.88W27.83W37.67W4

Astrometric Data

Parallax

16.544 mas

Total Proper Motion

117.406 mas/yr

PM Right Ascension

47.94 mas/yr

PM Declination

107.18 mas/yr

Galactic Cartesian (pc)

x = -0.806 · y = -0.113 · z = -0.581

Equatorial (J2000)

RA 187.99484° · Dec -35.55445°

Galactic ℓ, b

298.485° · 27.149°

Ecliptic λ, β

202.581° · -29.241°

HTM-20 index

1162303820

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