Key parameters at a glance

A radius of 8.18 Earth radii
A mass of 50.90 Earth masses
Surface gravity around 0.76 g
An orbital period of 190.323 days
Semi-major axis 0.7210 AU
Equilibrium temperature 426 K (153 °C)
Distance from Earth 1,104.79 light-years
Earth Similarity Index 0.337
Travel time at Voyager 1 speed 19,483,054 years

1 sibling around Kepler-108

Kepler-108 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-108 b	Neptune-like	8.65	56.00	49.184	669	2014
Kepler-108 c this	Neptune-like	8.18	50.90	190.323	426	2014

Kepler-108 c Planet Profile

Physical Specs

Radius

8.18 R⊕

Radius (Jupiter)

0.730 R♃

Mass

50.90 M⊕

Mass (Jupiter)

0.160 M♃

Density

0.51 g/cm³

Surface Gravity

0.76 g (Earth)

Classification

Planet Type

Neptune-like

ESI Score 0.337

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

#144of 574

top 24.9%

This planet

8.18R⊕

Neptune-like median

6.39R⊕

Nearest-size peers

K2-281 b 8.18 R⊕ HD 13724 c 8.18 R⊕ KMT-2024-BLG-2005L b 8.18 R⊕

Metric	Earth	Kepler-108 c	Jupiter
Radius (R⊕)	1.00	8.18	11.21
Mass (M⊕)	1.00	50.90	317.83
Density (g/cm³)	5.51	0.51	1.33
Surface Gravity (g)	1.00	0.76	2.53
Insolation (S⊕)	1.00	7.80	0.037

Star Catalogue Identifiers

TIC

TIC 271164755

Gaia DR2

Gaia DR2 2080062630075994624

System

Kepler-108

Percentile among Neptune-like cohort

Radius 8.180 R⊕ · percentile 74 / cohort 574

Mass 50.900 M⊕ · percentile 71 / cohort 574

Orbital period 190.32 d · percentile 88 / cohort 524

Distance 338.73 pc · percentile 50 / cohort 572

ESI 0.337 · percentile 60 / cohort 574

Orbit & Habitability

Orbital Dynamics

Period

190.323 days

Semi-major axis

0.7210 AU

Eccentricity

0.040

Inclination

89.24 °

Year Length

A year here lasts approximately 190.32 Earth days (52.1% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.7210 AU.

Transit Fingerprint

Depth

0.114 %

Duration

15.700 h

Impact parameter b

0.810

Rp / R★

0.032970

Transit midpoint (BJD)

2,455,145.6732

Photometric dip

Transit produces a flux drop of 1,142 ppm lasting ≈ 15.70 h.

Extended Orbital Architecture

Planet / star radius ratio

0.032970

Semi-major axis / stellar radius

70.810

Impact parameter (b)

0.810

Transit mid-time (BJD)

2,455,145.6732

Angular separation (arcsec)

2.13000

Eq. Temperature

426K

(153 °C)

Insolation (S⊕)

7.80

Earth = 1.00

Earth Similarity (ESI)

0.337

0 = alien, 1 = Earth-identical

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

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

Discovery cohort

Planets confirmed in 2014 at Kepler (12 shown).

Kepler-186 e · Super-Earth Kepler-395 c · Super-Earth Kepler-220 e · Super-Earth Kepler-249 d · Super-Earth Kepler-296 f · Super-Earth Kepler-367 c · Rocky Terrestrial Kepler-296 e · Super-Earth Kepler-155 c · Sub-Neptune Kepler-138 d · Super-Earth Kepler-333 c · Rocky Terrestrial Kepler-331 d · Super-Earth Kepler-267 d · Sub-Neptune

Host System: Kepler-108

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,854 K — hotter than the Sun (5,778 K)

Estimated Age

3.89 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

2.192 R☉

Stellar Mass

1.247 M☉

Metallicity [Fe/H]

0.33

Extended Stellar Properties

Surface gravity (log g)

3.895 dex

Stellar density

0.243 g/cm³

Metallicity ratio

[M/H]

Distance

338.73 parsec

Light-years 1,104.79 ly

V-band magnitude

12.66 mag

Voyager-speed travel 19,483,054 yr