Confirmed Exoplanet Discovered 2021

TOI-431 b

A super-earth orbiting the k-type orange TOI-431, located approximately 106.2 light-years from Earth.

Key parameters at a glance

  • A radius of 1.28 Earth radii
  • A mass of 3.07 Earth masses
  • Surface gravity around 1.87 g
  • An orbital period of 0.490 days
  • Semi-major axis 0.0113 AU
  • Equilibrium temperature 1,862 K (1589 °C)
  • Distance from Earth 106.22 light-years
  • Earth Similarity Index 0.142
  • Travel time at Voyager 1 speed 1,873,268 years
  • Almost certainly tidally locked to its host star given the close orbit

2 siblings around TOI-431

TOI-431 b shares its host star with 2 other confirmed planets. Side-by-side measurements below.

Planet Type Radius (R⊕) Mass (M⊕) Period (d) Eq. T (K) Year
TOI-431 b this Super-Earth 1.28 3.07 0.490 1,862 2021
TOI-431 c Super-Earth 1.49 2.83 4.849 867 2021
TOI-431 d Sub-Neptune 3.29 9.90 12.461 633 2021

TOI-431 b Planet Profile

Physical Specs

Radius
1.28 R⊕
Radius (Jupiter)
0.114 R♃
Mass
3.07 M⊕
Mass (Jupiter)
0.010 M♃
Density
8.00 g/cm³
Surface Gravity
1.87 g (Earth)

Classification

Planet Type

Super-Earth

ESI Score 0.142
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

#1117of 1176

top 94.9%

This planet

1.28R⊕

Super-Earth median

1.60R⊕

Nearest-size peers

Metric Earth TOI-431 b Jupiter
Radius (R⊕)1.001.2811.21
Mass (M⊕)1.003.07317.83
Density (g/cm³)5.518.001.33
Surface Gravity (g)1.001.872.53
Insolation (S⊕)1.002,120.450.037

Alternative Mass Estimates

Method Value Interpretation
Best measured mass 3.070 M⊕ Direct mass measurement (not derived).

Star Catalogue Identifiers

HIP

HIP 26013

TIC

TIC 31374837

Gaia DR2

Gaia DR2 2908664557091200768

Gaia DR3

Gaia DR3 2908664557091200768

System

TOI-431

Percentile among Super-Earth cohort

Radius 1.280 R⊕ · percentile 4 / cohort 1176
Mass 3.070 M⊕ · percentile 42 / cohort 1176
Orbital period 0.49 d · percentile 1 / cohort 1164
Distance 32.57 pc · percentile 7 / cohort 1171
ESI 0.142 · percentile 3 / cohort 1176

Orbit & Habitability

Orbital Dynamics

Period
0.490 days
Semi-major axis
0.0113 AU
Eccentricity
0.000
Inclination
84.30 °

Year Length

A year here lasts roughly 11.8 hours long on a nearly circular orbit at a mean orbital distance of 0.0113 AU.

Transit Fingerprint

Depth

0.029 %

Duration

1.012 h

Impact parameter b

0.340

Rp / R★

0.016000

Transit midpoint (BJD)

2,458,627.5380

Photometric dip

Transit produces a flux drop of 291 ppm lasting ≈ 1.01 h.

Extended Orbital Architecture

Planet / star radius ratio

0.016000

Semi-major axis / stellar radius

3.420

Impact parameter (b)

0.340

RV semi-amplitude (K)

2.880 m/s

Transit mid-time (BJD)

2,458,627.5380

Long. of periastron (ω)

0.00°

Angular separation (arcsec)

0.34700

Eq. Temperature

1,862K

(1589 °C)

Insolation (S⊕)

2,120.45

Earth = 1.00

Earth Similarity (ESI)

0.142

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.

Transit timing variations

Gravitational interactions from neighbours have been detected.

Discovery Paper

Primary reference

Osborn et al. 2021

Instrument

TESS CCD Array

Publication

2021-10

Observation locale

Space

Host System: TOI-431

Spectral Class

K-type orange

Effective Temperature

4,850 K — cooler than the Sun (5,778 K)

Estimated Age

Stellar Radius

0.731 R☉

Stellar Mass

0.780 M☉

Metallicity [Fe/H]

0.20

Extended Stellar Properties

Surface gravity (log g)

4.600 dex

Stellar density

2.940 g/cm³

Rotational v·sin i

2.50 km/s

Rotation period

30.50 days

Metallicity ratio

[Fe/H]

Distance
32.57 parsec
Light-years 106.22 ly
V-band magnitude
9.12 mag
Voyager-speed travel 1,873,268 yr

Multi-band Host Photometry — 11 bands

6.510.110.10B9.12V8.79Gaia8.17TESS7.31J6.85H6.72K6.65W16.71W26.67W36.54W4

Astrometric Data

Parallax

30.675 mas

Total Proper Motion

151.700 mas/yr

PM Right Ascension

16.80 mas/yr

PM Declination

150.77 mas/yr

Galactic Cartesian (pc)

x = 0.105 · y = 0.887 · z = -0.450

Equatorial (J2000)

RA 83.26925° · Dec -26.72387°

Galactic ℓ, b

230.329° · -28.137°

Ecliptic λ, β

80.634° · -49.945°

HTM-20 index

556649667

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