Confirmed Exoplanet Discovered 2021

TOI-431 c

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 1.49 Earth radii
  • A mass of 2.83 Earth masses
  • Surface gravity around 1.27 g
  • An orbital period of 4.849 days
  • Semi-major axis 0.0520 AU
  • Equilibrium temperature 867 K (594 °C)
  • Distance from Earth 106.22 light-years
  • Earth Similarity Index 0.348
  • 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 c 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 Super-Earth 1.28 3.07 0.490 1,862 2021
TOI-431 c this 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 c Planet Profile

Physical Specs

Radius
1.49 R⊕
Radius (Jupiter)
0.133 R♃
Mass
2.83 M⊕
Mass (Jupiter)
0.009 M♃
Density
4.70 g/cm³
Surface Gravity
1.27 g (Earth)

Classification

Planet Type

Super-Earth

ESI Score 0.348
HZ Position Unknown
Controversial No

Discovery

Year 2021
Method Radial Velocity
Facility La Silla Observatory
Telescope 3.6 m ESO Telescope

Size rank in cohort

Rank by radius

#766of 1176

top 65.1%

This planet

1.49R⊕

Super-Earth median

1.60R⊕

Nearest-size peers

Metric Earth TOI-431 c Jupiter
Radius (R⊕)1.001.4911.21
Mass (M⊕)1.002.83317.83
Density (g/cm³)5.514.701.33
Surface Gravity (g)1.001.272.53
Insolation (S⊕)1.000.037

Alternative Mass Estimates

Method Value Interpretation
Minimum mass (M sin i) 2.830 M⊕ Lower bound from radial-velocity fitting.

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 1.490 R⊕ · percentile 34 / cohort 1176
Mass 2.830 M⊕ · percentile 32 / cohort 1176
Orbital period 4.85 d · percentile 39 / cohort 1164
Distance 32.57 pc · percentile 7 / cohort 1171
ESI 0.348 · percentile 50 / cohort 1176

Orbit & Habitability

Orbital Dynamics

Period
4.849 days
Semi-major axis
0.0520 AU
Eccentricity
0.000
Inclination
86.35 °

Year Length

A year here lasts approximately 4.85 Earth days (1.3% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0520 AU.

Extended Orbital Architecture

RV semi-amplitude (K)

1.230 m/s

Transit mid-time (BJD)

2,458,625.9000

Long. of periastron (ω)

0.00°

Angular separation (arcsec)

1.60000

Eq. Temperature

867K

(594 °C)

Insolation (S⊕)

Earth = 1.00

Earth Similarity (ESI)

0.348

0 = alien, 1 = Earth-identical

Insufficient insolation data — the surface is too hot to retain surface water. Close-orbiting tidally-locked around a cool host.

Discovery Paper

Primary reference

Osborn et al. 2021

Instrument

HARPS Spectrograph

Publication

2021-10

Observation locale

Ground

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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