Confirmed Exoplanet Discovered 2023

TOI-908 b

A sub-neptune orbiting the g-type yellow (sun-like) TOI-908, located approximately 573.2 light-years from Earth.

Key parameters at a glance

  • A radius of 3.19 Earth radii
  • A mass of 16.14 Earth masses
  • Surface gravity around 1.59 g
  • An orbital period of 3.184 days
  • Semi-major axis 0.0417 AU
  • Equilibrium temperature 1,317 K (1044 °C)
  • Distance from Earth 573.21 light-years
  • Earth Similarity Index 0.177
  • Travel time at Voyager 1 speed 10,108,604 years

TOI-908 b Planet Profile

Physical Specs

Radius
3.19 R⊕
Radius (Jupiter)
0.284 R♃
Mass
16.14 M⊕
Mass (Jupiter)
0.051 M♃
Density
2.74 g/cm³
Surface Gravity
1.59 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.177
HZ Position Inner
Controversial No

Discovery

Year 2023
Method Transit
Facility Transiting Exoplanet Survey Satellite (TESS)
Telescope 0.1 m TESS Telescope

Size rank in cohort

Rank by radius

#364of 1978

top 18.4%

This planet

3.19R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

Metric Earth TOI-908 b Jupiter
Radius (R⊕)1.003.1911.21
Mass (M⊕)1.0016.14317.83
Density (g/cm³)5.512.741.33
Surface Gravity (g)1.001.592.53
Insolation (S⊕)1.0080.880.037

Alternative Mass Estimates

Method Value Interpretation
Best measured mass 16.137 M⊕ Direct mass measurement (not derived).

Star Catalogue Identifiers

TIC

TIC 350153977

Gaia DR2

Gaia DR2 4619238087059206784

Gaia DR3

Gaia DR3 4619238087059206784

System

TOI-908

Percentile among Sub-Neptune cohort

Radius 3.186 R⊕ · percentile 82 / cohort 1978
Mass 16.137 M⊕ · percentile 94 / cohort 1978
Orbital period 3.18 d · percentile 5 / cohort 1946
Distance 175.75 pc · percentile 27 / cohort 1975
ESI 0.177 · percentile 4 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period
3.184 days
Semi-major axis
0.0417 AU
Eccentricity
0.132
Inclination
86.48 °

Year Length

A year here lasts approximately 3.18 Earth days (0.9% of a terrestrial year) on a mildly elliptical path at a mean orbital distance of 0.0417 AU.

Transit Fingerprint

Depth

0.085 %

Duration

2.457 h

Impact parameter b

0.536

Rp / R★

0.028000

Transit midpoint (BJD)

2,459,384.2920

Photometric dip

Transit produces a flux drop of 850 ppm lasting ≈ 2.46 h.

Extended Orbital Architecture

Planet / star radius ratio

0.028000

Impact parameter (b)

0.536

RV semi-amplitude (K)

7.244 m/s

Transit mid-time (BJD)

2,459,384.2920

Long. of periastron (ω)

35.86°

Angular separation (arcsec)

0.23700

Eq. Temperature

1,317K

(1044 °C)

Insolation (S⊕)

80.88

Earth = 1.00

Earth Similarity (ESI)

0.177

0 = alien, 1 = Earth-identical

Inside the inner HZ boundary (too hot for liquid water) — the dayside is scorched.

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

Hawthorn et al. 2023

Instrument

TESS CCD Array

Publication

2023-06

Observation locale

Space

Host System: TOI-908

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,626 K — cooler than the Sun (5,778 K)

Estimated Age

4.60 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

1.028 R☉

Stellar Mass

0.950 M☉

Metallicity [Fe/H]

0.08

Extended Stellar Properties

Surface gravity (log g)

4.450 dex

Stellar density

1.235 g/cm³

Rotational v·sin i

2.56 km/s

Rotation period

21.93 days

Metallicity ratio

[Fe/H]

Distance
175.75 parsec
Light-years 573.21 ly
V-band magnitude
11.32 mag
Voyager-speed travel 10,108,604 yr

Multi-band Host Photometry — 11 bands

9.312.012.01B11.32V11.11Gaia10.65TESS10.04J9.73H9.64K9.61W19.66W29.60W39.34W4

Astrometric Data

Parallax

5.661 mas

Total Proper Motion

5.847 mas/yr

PM Right Ascension

5.84 mas/yr

PM Declination

-0.31 mas/yr

Galactic Cartesian (pc)

x = 0.091 · y = 0.122 · z = -0.988

Equatorial (J2000)

RA 53.15943° · Dec -81.25075°

Galactic ℓ, b

296.145° · -33.637°

Ecliptic λ, β

287.951° · -72.790°

HTM-20 index

-1974205409

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