Confirmed Exoplanet Discovered 2023

TOI-4551 b

A gas giant orbiting the k-type orange TOI-4551, located approximately 704.5 light-years from Earth.

Key parameters at a glance

  • A radius of 11.86 Earth radii
  • A mass of 473.56 Earth masses
  • Surface gravity around 3.37 g
  • An orbital period of 9.956 days
  • Semi-major axis 0.0994 AU
  • Equilibrium temperature 1,655 K (1382 °C)
  • Distance from Earth 704.45 light-years
  • Earth Similarity Index 0.092
  • Travel time at Voyager 1 speed 12,422,998 years
  • Almost certainly tidally locked to its host star given the close orbit

TOI-4551 b Planet Profile

Physical Specs

Radius
11.86 R⊕
Radius (Jupiter)
1.058 R♃
Mass
473.56 M⊕
Mass (Jupiter)
1.490 M♃
Density
1.74 g/cm³
Surface Gravity
3.37 g (Earth)

Classification

Planet Type

Gas Giant

ESI Score 0.092
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

#1554of 1771

top 87.7%

This planet

11.86R⊕

Gas Giant median

13.52R⊕

Nearest-size peers

Metric Earth TOI-4551 b Jupiter
Radius (R⊕)1.0011.8611.21
Mass (M⊕)1.00473.56317.83
Density (g/cm³)5.511.741.33
Surface Gravity (g)1.003.372.53
Insolation (S⊕)1.001,247.740.037

Alternative Mass Estimates

Method Value Interpretation
Best measured mass 473.564 M⊕ Direct mass measurement (not derived).

Star Catalogue Identifiers

TIC

TIC 204650483

Gaia DR2

Gaia DR2 3476605537386300032

Gaia DR3

Gaia DR3 3476605537386300032

System

TOI-4551

Percentile among Gas Giant cohort

Radius 11.859 R⊕ · percentile 12 / cohort 1771
Mass 473.564 M⊕ · percentile 47 / cohort 1747
Orbital period 9.96 d · percentile 44 / cohort 1533
Distance 215.99 pc · percentile 52 / cohort 1759
ESI 0.092 · percentile 24 / cohort 1771

Orbit & Habitability

Orbital Dynamics

Period
9.956 days
Semi-major axis
0.0994 AU
Eccentricity
0.101
Inclination
86.90 °

Year Length

A year here lasts approximately 9.96 Earth days (2.7% of a terrestrial year) on a mildly elliptical path at a mean orbital distance of 0.0994 AU.

Transit Fingerprint

Depth

0.102 %

Duration

10.474 h

Impact parameter b

0.310

Rp / R★

0.030800

Transit midpoint (BJD)

2,458,575.6597

Photometric dip

Transit produces a flux drop of 1,024 ppm lasting ≈ 10.47 h.

Extended Orbital Architecture

Planet / star radius ratio

0.030800

Impact parameter (b)

0.310

RV semi-amplitude (K)

117.300 m/s

Transit mid-time (BJD)

2,458,575.6597

Long. of periastron (ω)

2.37°

Angular separation (arcsec)

0.46000

Eq. Temperature

1,655K

(1382 °C)

Insolation (S⊕)

1,247.74

Earth = 1.00

Earth Similarity (ESI)

0.092

0 = alien, 1 = Earth-identical

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

Pereira et al. 2023

Instrument

TESS CCD Array

Publication

2023-11

Observation locale

Space

Host System: TOI-4551

Spectral Class

K-type orange

Effective Temperature

4,896 K — cooler than the Sun (5,778 K)

Estimated Age

4.92 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

3.550 R☉

Stellar Mass

1.310 M☉

Metallicity [Fe/H]

0.23

Extended Stellar Properties

Surface gravity (log g)

3.480 dex

Stellar density

0.028 g/cm³

Systemic radial velocity

41.29 km/s

Rotational v·sin i

2.84 km/s

Metallicity ratio

[Fe/H]

Distance
215.99 parsec
Light-years 704.45 ly
V-band magnitude
9.97 mag
Voyager-speed travel 12,422,998 yr

Multi-band Host Photometry — 11 bands

7.411.010.98B9.97V9.64Gaia9.03TESS8.13J7.68H7.52K7.41W17.54W27.46W37.56W4

Astrometric Data

Parallax

4.602 mas

Total Proper Motion

37.624 mas/yr

PM Right Ascension

-34.00 mas/yr

PM Declination

-16.11 mas/yr

Galactic Cartesian (pc)

x = -0.897 · y = -0.078 · z = -0.436

Equatorial (J2000)

RA 184.97876° · Dec -25.82785°

Galactic ℓ, b

294.100° · 36.503°

Ecliptic λ, β

195.276° · -21.632°

HTM-20 index

1410731852

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