Key parameters at a glance

A radius of 0.67 Earth radii
A mass of 0.23 Earth masses
Surface gravity around 0.51 g
An orbital period of 8.703 days
Semi-major axis 0.0847 AU
Equilibrium temperature 951 K (678 °C)
Distance from Earth 1,586.90 light-years
Earth Similarity Index 0.304
Travel time at Voyager 1 speed 27,984,962 years

2 siblings around Kepler-431

Kepler-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
Kepler-431 b	Rocky Terrestrial	0.76	0.37	6.803	1,032	2015
Kepler-431 c this	Rocky Terrestrial	0.67	0.23	8.703	951	2015
Kepler-431 d	Rocky Terrestrial	1.11	1.41	11.922	856	2015

Kepler-431 c Planet Profile

Physical Specs

Radius

0.67 R⊕

Radius (Jupiter)

0.060 R♃

Mass

0.23 M⊕

Mass (Jupiter)

0.001 M♃

Density

4.22 g/cm³

Surface Gravity

0.51 g (Earth)

Classification

Planet Type

Rocky Terrestrial

ESI Score 0.304

HZ Position Inner

Controversial No

Discovery

Year 2015

Method Transit

Facility Kepler

Telescope 0.95 m Kepler Telescope

Size rank in cohort

Rank by radius

#537of 570

top 94.0%

This planet

0.67R⊕

Rocky Terrestrial median

1.01R⊕

Nearest-size peers

Kepler-271 d 0.66 R⊕ Kepler-1558 b 0.68 R⊕ LHS 1678 b 0.69 R⊕

Metric	Earth	Kepler-431 c	Jupiter
Radius (R⊕)	1.00	0.67	11.21
Mass (M⊕)	1.00	0.23	317.83
Density (g/cm³)	5.51	4.22	1.33
Surface Gravity (g)	1.00	0.51	2.53
Insolation (S⊕)	1.00	415.55	0.037

Star Catalogue Identifiers

TIC

TIC 123231081

Gaia DR2

Gaia DR2 2116862833283266432

Gaia DR3

Gaia DR3 2116862833283266432

System

Kepler-431

Percentile among Rocky Terrestrial cohort

Radius 0.668 R⊕ · percentile 6 / cohort 570

Mass 0.229 M⊕ · percentile 4 / cohort 570

Orbital period 8.70 d · percentile 76 / cohort 567

Distance 486.55 pc · percentile 62 / cohort 566

ESI 0.304 · percentile 40 / cohort 570

Orbit & Habitability

Orbital Dynamics

Period

8.703 days

Semi-major axis

0.0847 AU

Eccentricity

0.000

Inclination

82.35 °

Year Length

A year here lasts approximately 8.70 Earth days (2.4% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0847 AU.

Transit Fingerprint

Depth

0.003 %

Duration

4.807 h

Impact parameter b

0.087

Rp / R★

0.005600

Transit midpoint (BJD)

2,454,973.1553

Photometric dip

Transit produces a flux drop of 32 ppm lasting ≈ 4.81 h.

Extended Orbital Architecture

Planet / star radius ratio

0.005600

Semi-major axis / stellar radius

6.650

Impact parameter (b)

0.087

Transit mid-time (BJD)

2,454,973.1553

Angular separation (arcsec)

0.17400

Eq. Temperature

951K

(678 °C)

Insolation (S⊕)

415.55

Earth = 1.00

Earth Similarity (ESI)

0.304

0 = alien, 1 = Earth-identical

Inside the inner HZ boundary (too hot for liquid water) — the surface is too hot to retain surface water.

Discovery Paper

Primary reference

Everett et al. 2015

Instrument

Kepler CCD Array

Publication

2015-02

Observation locale

Space

Discovery cohort

Planets confirmed in 2015 at Kepler (12 shown).

Kepler-438 b · Rocky Terrestrial Kepler-445 d · Super-Earth Kepler-442 b · Super-Earth Kepler-439 b · Sub-Neptune Kepler-437 b · Sub-Neptune Kepler-440 b · Super-Earth KIC 8540376 c · Sub-Neptune Kepler-445 b · Super-Earth Kepler-446 d · Super-Earth Kepler-436 b · Sub-Neptune Kepler-445 c · Sub-Neptune Kepler-443 b · Sub-Neptune

Host System: Kepler-431

Spectral Class

F-type yellow-white

Effective Temperature

6,004 K — hotter than the Sun (5,778 K)

Estimated Age

4.34 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

1.092 R☉

Stellar Mass

1.071 M☉

Metallicity [Fe/H]

0.07

Extended Stellar Properties

Surface gravity (log g)

4.400 dex

Stellar density

0.270 g/cm³

Systemic radial velocity

-9.00 km/s

Metallicity ratio

[Fe/H]

Distance

486.55 parsec

Light-years 1,586.90 ly

V-band magnitude

12.14 mag

Voyager-speed travel 27,984,962 yr

Multi-band Host Photometry — 16 bands

Astrometric Data

Parallax

2.027 mas

Total Proper Motion

7.958 mas/yr

PM Right Ascension

-6.00 mas/yr

PM Declination

-5.23 mas/yr

Galactic Cartesian (pc)

x = 0.140 · y = -0.715 · z = 0.685

Equatorial (J2000)

RA 281.11231° · Dec 43.22777°

Galactic ℓ, b

72.388° · 19.395°

Ecliptic λ, β

290.106° · 65.893°

HTM-20 index

-663223716