Confirmed Exoplanet Discovered 2014

Kepler-231 c

A super-earth orbiting the m-type red dwarf Kepler-231, located approximately 1,032.7 light-years from Earth.

Key parameters at a glance

  • A radius of 1.93 Earth radii
  • A mass of 24.10 Earth masses
  • Surface gravity around 6.47 g
  • An orbital period of 19.272 days
  • Semi-major axis 0.1140 AU
  • Equilibrium temperature 393 K (120 °C)
  • Distance from Earth 1,032.67 light-years
  • Earth Similarity Index 0.471
  • Travel time at Voyager 1 speed 18,211,110 years
  • Almost certainly tidally locked to its host star given the close orbit

1 sibling around Kepler-231

Kepler-231 c shares its host star with 1 other confirmed planet. Side-by-side measurements below.

Planet Type Radius (R⊕) Mass (M⊕) Period (d) Eq. T (K) Year
Kepler-231 b Super-Earth 1.73 35.40 10.065 488 2014
Kepler-231 c this Super-Earth 1.93 24.10 19.272 393 2014

Kepler-231 c Planet Profile

Physical Specs

Radius
1.93 R⊕
Radius (Jupiter)
0.172 R♃
Mass
24.10 M⊕
Mass (Jupiter)
0.076 M♃
Density
0.97 g/cm³
Surface Gravity
6.47 g (Earth)

Classification

Planet Type

Super-Earth

ESI Score 0.471
HZ Position Inner
Controversial No

Discovery

Year 2014
Method Transit
Facility Kepler
Telescope 0.95 m Kepler Telescope

Size rank in cohort

Rank by radius

#85of 1176

top 7.1%

This planet

1.93R⊕

Super-Earth median

1.60R⊕

Nearest-size peers

Metric Earth Kepler-231 c Jupiter
Radius (R⊕)1.001.9311.21
Mass (M⊕)1.0024.10317.83
Density (g/cm³)5.510.971.33
Surface Gravity (g)1.006.472.53
Insolation (S⊕)1.006.270.037

Alternative Mass Estimates

Method Value Interpretation
Best measured mass 24.100 M⊕ Direct mass measurement (not derived).

Star Catalogue Identifiers

TIC

TIC 27006192

Gaia DR2

Gaia DR2 2135223204298512128

Gaia DR3

Gaia DR3 2135223204298512128

System

Kepler-231

Percentile among Super-Earth cohort

Radius 1.930 R⊕ · percentile 92 / cohort 1176
Mass 24.100 M⊕ · percentile 98 / cohort 1176
Orbital period 19.27 d · percentile 84 / cohort 1164
Distance 316.62 pc · percentile 33 / cohort 1171
ESI 0.471 · percentile 70 / cohort 1176

Orbit & Habitability

Orbital Dynamics

Period
19.272 days
Semi-major axis
0.1140 AU
Eccentricity
0.000
Inclination
89.97 °

Year Length

A year here lasts approximately 19.27 Earth days (5.3% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.1140 AU.

Transit Fingerprint

Depth

0.122 %

Duration

3.209 h

Impact parameter b

0.870

Rp / R★

0.031590

Transit midpoint (BJD)

2,455,019.7691

Photometric dip

Transit produces a flux drop of 1,220 ppm lasting ≈ 3.21 h.

Extended Orbital Architecture

Planet / star radius ratio

0.031590

Semi-major axis / stellar radius

45.400

Impact parameter (b)

0.870

Transit mid-time (BJD)

2,455,019.7691

Angular separation (arcsec)

0.36000

Eq. Temperature

393K

(120 °C)

Insolation (S⊕)

6.27

Earth = 1.00

Earth Similarity (ESI)

0.471

0 = alien, 1 = Earth-identical

Inside the inner HZ boundary (too hot for liquid water) — the surface is too hot to retain surface water. Close-orbiting tidally-locked around a cool host.

Detection Signatures

Transit photometry

A transit dip has been observed from at least one telescope.

Transit timing variations

Gravitational interactions from neighbours have been detected.

Discovery Paper

Primary reference

Rowe et al. 2014

Instrument

Kepler CCD Array

Publication

2014-03

Observation locale

Space

Host System: Kepler-231

Spectral Class

M-type red dwarf

Effective Temperature

3,767 K — cooler than the Sun (5,778 K)

Estimated Age

3.15 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

0.490 R☉

Stellar Mass

0.580 M☉

Metallicity [Fe/H]

-0.10

Extended Stellar Properties

Surface gravity (log g)

4.779 dex

Stellar density

7.162 g/cm³

Metallicity ratio

[Fe/H]

Distance
316.62 parsec
Light-years 1,032.67 ly
V-band magnitude
15.81 mag
Voyager-speed travel 18,211,110 yr

Multi-band Host Photometry — 16 bands

9.117.017.02B15.81V15.39Gaia15.39Kepler14.57TESS16.62Sloan g15.38Sloan r14.86Sloan i14.59Sloan z13.41J12.78H12.59K12.54W112.55W212.36W39.10W4

Astrometric Data

Parallax

3.130 mas

Total Proper Motion

13.589 mas/yr

PM Right Ascension

5.04 mas/yr

PM Declination

-12.62 mas/yr

Galactic Cartesian (pc)

x = 0.258 · y = -0.581 · z = 0.772

Equatorial (J2000)

RA 293.97339° · Dec 50.53185°

Galactic ℓ, b

82.916° · 14.061°

Ecliptic λ, β

318.832° · 69.936°

HTM-20 index

479015227

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