Confirmed Exoplanet Discovered 2021

TOI-559 b

A gas giant orbiting the g-type yellow (sun-like) TOI-559, located approximately 760.8 light-years from Earth.

Key parameters at a glance

  • A radius of 12.23 Earth radii
  • A mass of 1,910.15 Earth masses
  • Surface gravity around 12.77 g
  • An orbital period of 6.984 days
  • Semi-major axis 0.0723 AU
  • Equilibrium temperature 1,180 K (907 °C)
  • Distance from Earth 760.81 light-years
  • Earth Similarity Index 0.147
  • Travel time at Voyager 1 speed 13,416,902 years

TOI-559 b Planet Profile

Physical Specs

Radius
12.23 R⊕
Radius (Jupiter)
1.091 R♃
Mass
1,910.15 M⊕
Mass (Jupiter)
6.010 M♃
Density
5.74 g/cm³
Surface Gravity
12.77 g (Earth)

Classification

Planet Type

Gas Giant

ESI Score 0.147
HZ Position Inner
Controversial No

Discovery

Year 2021
Method Transit
Facility Transiting Exoplanet Survey Satellite (TESS)
Telescope 0.1 m TESS Telescope

Size rank in cohort

Rank by radius

#1399of 1771

top 78.9%

This planet

12.23R⊕

Gas Giant median

13.52R⊕

Nearest-size peers

Metric Earth TOI-559 b Jupiter
Radius (R⊕)1.0012.2311.21
Mass (M⊕)1.001,910.15317.83
Density (g/cm³)5.515.741.33
Surface Gravity (g)1.0012.772.53
Insolation (S⊕)1.00404.920.037

Alternative Mass Estimates

Method Value Interpretation
Best measured mass 1,910.149 M⊕ Direct mass measurement (not derived).

Star Catalogue Identifiers

TIC

TIC 209459275

Gaia DR2

Gaia DR2 5057924844082070016

Gaia DR3

Gaia DR3 5057924844082070016

System

TOI-559

Percentile among Gas Giant cohort

Radius 12.229 R⊕ · percentile 21 / cohort 1771
Mass 1,910.149 M⊕ · percentile 79 / cohort 1747
Orbital period 6.98 d · percentile 41 / cohort 1533
Distance 233.27 pc · percentile 54 / cohort 1759
ESI 0.147 · percentile 36 / cohort 1771

Orbit & Habitability

Orbital Dynamics

Period
6.984 days
Semi-major axis
0.0723 AU
Eccentricity
0.151
Inclination
89.08 °

Year Length

A year here lasts approximately 6.98 Earth days (1.9% of a terrestrial year) on a mildly elliptical path at a mean orbital distance of 0.0723 AU.

Transit Fingerprint

Depth

0.828 %

Duration

5.150 h

Impact parameter b

0.230

Rp / R★

0.090970

Transit midpoint (BJD)

2,458,893.8131

Photometric dip

Transit produces a flux drop of 8,276 ppm lasting ≈ 5.15 h.

Extended Orbital Architecture

Planet / star radius ratio

0.090970

Semi-major axis / stellar radius

12.610

Impact parameter (b)

0.230

RV semi-amplitude (K)

633.000 m/s

Transit mid-time (BJD)

2,458,893.8131

Long. of periastron (ω)

-62.30°

Angular separation (arcsec)

0.31000

Eq. Temperature

1,180K

(907 °C)

Insolation (S⊕)

404.92

Earth = 1.00

Earth Similarity (ESI)

0.147

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

Ikwut Ukwa et al. 2022

Instrument

TESS CCD Array

Publication

2022-01

Observation locale

Space

Host System: TOI-559

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,925 K — hotter than the Sun (5,778 K)

Estimated Age

6.80 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

1.233 R☉

Stellar Mass

1.026 M☉

Metallicity [Fe/H]

-0.07

Extended Stellar Properties

Surface gravity (log g)

4.268 dex

Stellar density

0.774 g/cm³

Rotational v·sin i

4.08 km/s

Metallicity ratio

[Fe/H]

Distance
233.27 parsec
Light-years 760.81 ly
V-band magnitude
11.09 mag
Voyager-speed travel 13,416,902 yr

Multi-band Host Photometry — 11 bands

9.311.711.67B11.09V10.98Gaia10.57TESS9.99J9.72H9.64K9.61W19.65W29.61W39.33W4

Astrometric Data

Parallax

4.258 mas

Total Proper Motion

73.438 mas/yr

PM Right Ascension

-23.14 mas/yr

PM Declination

-69.70 mas/yr

Galactic Cartesian (pc)

x = 0.586 · y = 0.624 · z = -0.517

Equatorial (J2000)

RA 46.81862° · Dec -31.16300°

Galactic ℓ, b

228.915° · -60.184°

Ecliptic λ, β

32.048° · -46.301°

HTM-20 index

-1278849541

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