Key parameters at a glance

A radius of 0.57 Earth radii
A mass of 1.70 Earth masses
Surface gravity around 5.29 g
An orbital period of 7.071 days
Semi-major axis 0.0670 AU
Equilibrium temperature 777 K (504 °C)
Distance from Earth 351.58 light-years
Earth Similarity Index 0.247
Travel time at Voyager 1 speed 6,200,168 years
Almost certainly tidally locked to its host star given the close orbit

4 siblings around Kepler-102

Kepler-102 c shares its host star with 4 other confirmed planets. Side-by-side measurements below.

Planet	Type	Radius (R⊕)	Mass (M⊕)	Period (d)	Eq. T (K)	Year
Kepler-102 b	Rocky Terrestrial	0.46	1.10	5.287	857	2014
Kepler-102 c this	Rocky Terrestrial	0.57	1.70	7.071	777	2014
Kepler-102 d	Rocky Terrestrial	1.15	3.00	10.312	686	2014
Kepler-102 e	Sub-Neptune	2.17	4.70	16.146	590	2013
Kepler-102 f	Rocky Terrestrial	0.86	4.30	27.454	495	2014

Kepler-102 c Planet Profile

Physical Specs

Radius

0.57 R⊕

Radius (Jupiter)

0.051 R♃

Mass

1.70 M⊕

Mass (Jupiter)

0.005 M♃

Density

52.00 g/cm³

Surface Gravity

5.29 g (Earth)

Classification

Planet Type

Rocky Terrestrial

ESI Score 0.247

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

#554of 570

top 97.0%

This planet

0.57R⊕

Rocky Terrestrial median

1.01R⊕

Nearest-size peers

GJ 238 b 0.57 R⊕ Kepler-42 d 0.57 R⊕ Kepler-444 e 0.55 R⊕

Metric	Earth	Kepler-102 c	Jupiter
Radius (R⊕)	1.00	0.57	11.21
Mass (M⊕)	1.00	1.70	317.83
Density (g/cm³)	5.51	52.00	1.33
Surface Gravity (g)	1.00	5.29	2.53
Insolation (S⊕)	1.00	61.00	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Best measured mass	1.700 M⊕	Direct mass measurement (not derived).

Star Catalogue Identifiers

TIC

TIC 123357864

Gaia DR2

Gaia DR2 2119583201145735808

Gaia DR3

Gaia DR3 2119583201145735808

System

Kepler-102

Percentile among Rocky Terrestrial cohort

Radius 0.567 R⊕ · percentile 3 / cohort 570

Mass 1.700 M⊕ · percentile 69 / cohort 570

Orbital period 7.07 d · percentile 68 / cohort 567

Distance 107.80 pc · percentile 24 / cohort 566

ESI 0.247 · percentile 25 / cohort 570

Orbit & Habitability

Orbital Dynamics

Period

7.071 days

Semi-major axis

0.0670 AU

Eccentricity

0.094

Inclination

89.82 °

Year Length

A year here lasts approximately 7.07 Earth days (1.9% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0670 AU.

Transit Fingerprint

Depth

0.006 %

Duration

2.751 h

Impact parameter b

0.060

Rp / R★

0.008560

Transit midpoint (BJD)

2,454,972.9746

Photometric dip

Transit produces a flux drop of 63 ppm lasting ≈ 2.75 h.

Extended Orbital Architecture

Planet / star radius ratio

0.008560

Semi-major axis / stellar radius

19.718

Impact parameter (b)

0.060

RV semi-amplitude (K)

0.660 m/s

Transit mid-time (BJD)

2,454,972.9746

Angular separation (arcsec)

0.62200

Eq. Temperature

777K

(504 °C)

Insolation (S⊕)

61.00

Earth = 1.00

Earth Similarity (ESI)

0.247

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.

Discovery Paper

Primary reference

Marcy et al. 2014

Instrument

Kepler CCD Array

Publication

2014-02

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-102

Spectral Class

K-type orange

Effective Temperature

4,909 K — cooler than the Sun (5,778 K)

Estimated Age

1.10 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

0.724 R☉

Stellar Mass

0.803 M☉

Metallicity [Fe/H]

0.11

Extended Stellar Properties

Surface gravity (log g)

4.600 dex

Stellar density

2.020 g/cm³

Systemic radial velocity

-27.67 km/s

Rotational v·sin i

0.50 km/s

Rotation period

27.95 days

Metallicity ratio

[Fe/H]

Distance

107.80 parsec

Light-years 351.58 ly

V-band magnitude

12.07 mag

Voyager-speed travel 6,200,168 yr

Multi-band Host Photometry — 16 bands

Astrometric Data

Parallax

9.248 mas

Total Proper Motion

59.615 mas/yr

PM Right Ascension

-41.14 mas/yr

PM Declination

-43.14 mas/yr

Galactic Cartesian (pc)

x = 0.135 · y = -0.666 · z = 0.734

Equatorial (J2000)

RA 281.48247° · Dec 47.20783°

Galactic ℓ, b

76.484° · 20.435°

Ecliptic λ, β

292.976° · 69.733°

HTM-20 index

1736978485