Confirmed Exoplanet Discovered 2018

K2-232 b

A gas giant orbiting the f-type yellow-white K2-232, located approximately 426.4 light-years from Earth.

Key parameters at a glance

  • A radius of 11.21 Earth radii
  • A mass of 126.50 Earth masses
  • Surface gravity around 1.01 g
  • An orbital period of 11.168 days
  • Semi-major axis 0.1036 AU
  • Equilibrium temperature 1,030 K (757 °C)
  • Distance from Earth 426.35 light-years
  • Earth Similarity Index 0.125
  • Travel time at Voyager 1 speed 7,518,702 years

K2-232 b Planet Profile

Physical Specs

Radius
11.21 R⊕
Radius (Jupiter)
1.000 R♃
Mass
126.50 M⊕
Mass (Jupiter)
0.398 M♃
Density
0.41 g/cm³
Surface Gravity
1.01 g (Earth)

Classification

Planet Type

Gas Giant

ESI Score 0.125
HZ Position Inner
Controversial No

Discovery

Year 2018
Method Transit
Facility K2
Telescope 0.95 m Kepler Telescope

Size rank in cohort

Rank by radius

#1629of 1771

top 91.9%

This planet

11.21R⊕

Gas Giant median

13.52R⊕

Nearest-size peers

Metric Earth K2-232 b Jupiter
Radius (R⊕)1.0011.2111.21
Mass (M⊕)1.00126.50317.83
Density (g/cm³)5.510.411.33
Surface Gravity (g)1.001.012.53
Insolation (S⊕)1.00312.160.037

Alternative Mass Estimates

Method Value Interpretation
Best measured mass 126.496 M⊕ Direct mass measurement (not derived).
Minimum mass (M sin i) 123.000 M⊕ Lower bound from radial-velocity fitting.
Computed mass 123.003 M⊕ Model-computed mass (e.g. from mass-radius relation).

Star Catalogue Identifiers

HD

HD 286123

TIC

TIC 68577662

Gaia DR2

Gaia DR2 3406687485600728192

Gaia DR3

Gaia DR3 3406687485600728192

System

K2-232

Percentile among Gas Giant cohort

Radius 11.209 R⊕ · percentile 8 / cohort 1771
Mass 126.496 M⊕ · percentile 9 / cohort 1747
Orbital period 11.17 d · percentile 45 / cohort 1533
Distance 130.72 pc · percentile 40 / cohort 1759
ESI 0.125 · percentile 33 / cohort 1771

Orbit & Habitability

Orbital Dynamics

Period
11.168 days
Semi-major axis
0.1036 AU
Eccentricity
0.258
Inclination
89.14 °

Year Length

A year here lasts approximately 11.17 Earth days (3.1% of a terrestrial year) on a mildly elliptical path at a mean orbital distance of 0.1036 AU.

Transit Fingerprint

Depth

0.966 %

Duration

5.030 h

Impact parameter b

0.108

Rp / R★

0.088680

Transit midpoint (BJD)

2,457,825.3498

Photometric dip

Transit produces a flux drop of 9,660 ppm lasting ≈ 5.03 h.

Extended Orbital Architecture

Planet / star radius ratio

0.088680

Semi-major axis / stellar radius

19.250

Impact parameter (b)

0.108

RV semi-amplitude (K)

33.420 m/s

Transit mid-time (BJD)

2,457,825.3498

Long. of periastron (ω)

207.00°

Angular separation (arcsec)

0.79200

Eq. Temperature

1,030K

(757 °C)

Insolation (S⊕)

312.16

Earth = 1.00

Earth Similarity (ESI)

0.125

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

Brahm et al. 2018

Instrument

Kepler CCD Array

Publication

2018-06

Observation locale

Space

Host System: K2-232

Spectral Class

F-type yellow-white

Effective Temperature

6,154 K — hotter than the Sun (5,778 K)

Estimated Age

1.43 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

1.161 R☉

Stellar Mass

1.188 M☉

Metallicity [Fe/H]

0.10

Extended Stellar Properties

Surface gravity (log g)

4.379 dex

Stellar density

0.782 g/cm³

Rotational v·sin i

4.16 km/s

Metallicity ratio

[Fe/H]

Distance
130.72 parsec
Light-years 426.35 ly
V-band magnitude
9.82 mag
Voyager-speed travel 7,518,702 yr

Multi-band Host Photometry — 15 bands

8.410.510.52B9.82V9.73Gaia9.79Kepler9.31TESS10.29Sloan g9.75Sloan r9.66Sloan i8.74J8.48H8.43K8.38W18.42W28.39W38.52W4

Astrometric Data

Parallax

7.621 mas

Total Proper Motion

78.609 mas/yr

PM Right Ascension

62.06 mas/yr

PM Declination

-48.24 mas/yr

Galactic Cartesian (pc)

x = 0.265 · y = 0.910 · z = 0.320

Equatorial (J2000)

RA 73.76679° · Dec 18.65432°

Galactic ℓ, b

182.071° · -15.316°

Ecliptic λ, β

74.600° · -3.922°

HTM-20 index

1581351767

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