Confirmed Exoplanet Discovered 2023

TOI-858 B b

A gas giant orbiting the g-type yellow (sun-like) TOI-858 B, located approximately 817.0 light-years from Earth.

Key parameters at a glance

  • A radius of 14.07 Earth radii
  • A mass of 349.61 Earth masses
  • Surface gravity around 1.77 g
  • An orbital period of 3.280 days
  • Semi-major axis 0.0444 AU
  • Equilibrium temperature 1,529 K (1256 °C)
  • Distance from Earth 816.98 light-years
  • Earth Similarity Index 0.083
  • Travel time at Voyager 1 speed 14,407,528 years

TOI-858 B b Planet Profile

Physical Specs

Radius
14.07 R⊕
Radius (Jupiter)
1.255 R♃
Mass
349.61 M⊕
Mass (Jupiter)
1.100 M♃
Density
0.69 g/cm³
Surface Gravity
1.77 g (Earth)

Classification

Planet Type

Gas Giant

ESI Score 0.083
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

#404of 1771

top 22.8%

This planet

14.07R⊕

Gas Giant median

13.52R⊕

Nearest-size peers

Metric Earth TOI-858 B b Jupiter
Radius (R⊕)1.0014.0711.21
Mass (M⊕)1.00349.61317.83
Density (g/cm³)5.510.691.33
Surface Gravity (g)1.001.772.53
Insolation (S⊕)1.00908.900.037

Alternative Mass Estimates

Method Value Interpretation
Best measured mass 349.611 M⊕ Direct mass measurement (not derived).

Star Catalogue Identifiers

TIC

TIC 198008005

Gaia DR2

Gaia DR2 4683737294569921664

Gaia DR3

Gaia DR3 4683737294569921664

System

TOI-858

Percentile among Gas Giant cohort

Radius 14.067 R⊕ · percentile 77 / cohort 1771
Mass 349.611 M⊕ · percentile 37 / cohort 1747
Orbital period 3.28 d · percentile 20 / cohort 1533
Distance 250.49 pc · percentile 56 / cohort 1759
ESI 0.083 · percentile 19 / cohort 1771

Orbit & Habitability

Orbital Dynamics

Period
3.280 days
Semi-major axis
0.0444 AU
Eccentricity
0.150
Inclination
86.80 °

Year Length

A year here lasts approximately 3.28 Earth days (0.9% of a terrestrial year) on a mildly elliptical path at a mean orbital distance of 0.0444 AU.

Transit Fingerprint

Depth

0.974 %

Duration

3.602 h

Impact parameter b

0.419

Transit midpoint (BJD)

2,458,386.4524

Photometric dip

Transit produces a flux drop of 9,740 ppm lasting ≈ 3.60 h.

Extended Orbital Architecture

Impact parameter (b)

0.419

RV semi-amplitude (K)

143.000 m/s

Transit mid-time (BJD)

2,458,386.4524

Sky-projected obliquity (λ)

99.30°

Angular separation (arcsec)

0.17700

Eq. Temperature

1,529K

(1256 °C)

Insolation (S⊕)

908.90

Earth = 1.00

Earth Similarity (ESI)

0.083

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

Hagelberg et al. 2023

Instrument

TESS CCD Array

Publication

2023-11

Observation locale

Space

Host System: TOI-858 B

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,842 K — hotter than the Sun (5,778 K)

Estimated Age

6.80 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

1.308 R☉

Stellar Mass

1.081 M☉

Metallicity [Fe/H]

0.15

Extended Stellar Properties

Surface gravity (log g)

4.238 dex

Stellar density

0.680 g/cm³

Rotational v·sin i

5.80 km/s

Metallicity ratio

[Fe/H]

Distance
250.49 parsec
Light-years 816.98 ly
V-band magnitude
11.18 mag
Voyager-speed travel 14,407,528 yr

Multi-band Host Photometry — 10 bands

9.011.211.18V11.07Gaia10.64TESS10.06J9.79H9.72K9.57W19.58W29.57W38.98W4

Astrometric Data

Parallax

3.963 mas

Total Proper Motion

15.547 mas/yr

PM Right Ascension

11.00 mas/yr

PM Declination

-10.99 mas/yr

Galactic Cartesian (pc)

x = 0.288 · y = 0.503 · z = -0.815

Equatorial (J2000)

RA 60.19983° · Dec -54.59292°

Galactic ℓ, b

264.984° · -46.143°

Ecliptic λ, β

25.452° · -71.404°

HTM-20 index

1166375966

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