Key parameters at a glance

A radius of 5.45 Earth radii
A mass of 58.47 Earth masses
Surface gravity around 1.97 g
An orbital period of 179.610 days
Semi-major axis 0.6679 AU
Equilibrium temperature 434 K (161 °C)
Distance from Earth 1,613.92 light-years
Earth Similarity Index 0.456
Travel time at Voyager 1 speed 28,461,553 years

1 sibling around Kepler-103

Kepler-103 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-103 b	Sub-Neptune	3.49	11.67	15.965	973	2014
Kepler-103 c this	Neptune-like	5.45	58.47	179.610	434	2014

Kepler-103 c Planet Profile

Physical Specs

Radius

5.45 R⊕

Radius (Jupiter)

0.487 R♃

Mass

58.47 M⊕

Mass (Jupiter)

0.184 M♃

Density

1.98 g/cm³

Surface Gravity

1.97 g (Earth)

Classification

Planet Type

Neptune-like

ESI Score 0.456

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

#321of 574

top 55.7%

This planet

5.45R⊕

Neptune-like median

6.39R⊕

Nearest-size peers

HD 105618 b 5.44 R⊕ KOI-1783.02 5.44 R⊕ HD 190360 c 5.44 R⊕

Metric	Earth	Kepler-103 c	Jupiter
Radius (R⊕)	1.00	5.45	11.21
Mass (M⊕)	1.00	58.47	317.83
Density (g/cm³)	5.51	1.98	1.33
Surface Gravity (g)	1.00	1.97	2.53
Insolation (S⊕)	1.00	5.97	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Best measured mass	58.470 M⊕	Direct mass measurement (not derived).
Minimum mass (M sin i)	30.445 M⊕	Lower bound from radial-velocity fitting.

Star Catalogue Identifiers

TIC

TIC 121865656

Gaia DR2

Gaia DR2 2101243789577188736

Gaia DR3

Gaia DR3 2101243789577188736

System

Kepler-103

Percentile among Neptune-like cohort

Radius 5.454 R⊕ · percentile 44 / cohort 574

Mass 58.470 M⊕ · percentile 76 / cohort 574

Orbital period 179.61 d · percentile 88 / cohort 524

Distance 494.83 pc · percentile 57 / cohort 572

ESI 0.456 · percentile 82 / cohort 574

Orbit & Habitability

Orbital Dynamics

Period

179.610 days

Semi-major axis

0.6679 AU

Eccentricity

0.103

Inclination

89.70 °

Year Length

A year here lasts approximately 179.61 Earth days (49.2% of a terrestrial year) on a mildly elliptical path at a mean orbital distance of 0.6679 AU.

Transit Fingerprint

Depth

0.128 %

Duration

13.755 h

Impact parameter b

0.440

Rp / R★

0.033510

Transit midpoint (BJD)

2,455,667.1597

Photometric dip

Transit produces a flux drop of 1,279 ppm lasting ≈ 13.76 h.

Extended Orbital Architecture

Planet / star radius ratio

0.033510

Semi-major axis / stellar radius

98.000

Impact parameter (b)

0.440

RV semi-amplitude (K)

5.900 m/s

Transit mid-time (BJD)

2,455,667.1597

Long. of periastron (ω)

-15.60°

Angular separation (arcsec)

1.35000

Eq. Temperature

434K

(161 °C)

Insolation (S⊕)

5.97

Earth = 1.00

Earth Similarity (ESI)

0.456

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.

Radial velocity

Stellar wobble has been measured spectroscopically.

Transit timing variations

Gravitational interactions from neighbours have been detected.

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-103

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

6,047 K — hotter than the Sun (5,778 K)

Estimated Age

6.03 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

1.492 R☉

Stellar Mass

1.212 M☉

Metallicity [Fe/H]

0.15

Extended Stellar Properties

Surface gravity (log g)

4.170 dex

Stellar density

0.350 g/cm³

Systemic radial velocity

-28.49 km/s

Rotational v·sin i

3.10 km/s

Rotation period

20.80 days

Activity index (log R'HK)

-5.069

Metallicity ratio

[Fe/H]

Distance

494.83 parsec

Light-years 1,613.92 ly

V-band magnitude

11.88 mag

Voyager-speed travel 28,461,553 yr

Multi-band Host Photometry — 16 bands

Astrometric Data

Parallax

1.992 mas

Total Proper Motion

8.936 mas/yr

PM Right Ascension

-1.24 mas/yr

PM Declination

-8.85 mas/yr

Galactic Cartesian (pc)

x = 0.249 · y = -0.724 · z = 0.644

Equatorial (J2000)

RA 288.98455° · Dec 40.06449°

Galactic ℓ, b

71.652° · 12.757°

Ecliptic λ, β

301.392° · 61.451°

HTM-20 index

-942703979