Key parameters at a glance

A radius of 1.56 Earth radii
A mass of 8.50 Earth masses
Surface gravity around 3.49 g
An orbital period of 9.341 days
Semi-major axis 0.0898 AU
Equilibrium temperature 1,143 K (870 °C)
Distance from Earth 1,802.98 light-years
Earth Similarity Index 0.218
Travel time at Voyager 1 speed 31,795,618 years

3 siblings around Kepler-338

Kepler-338 e shares its host star with 3 other confirmed planets. Side-by-side measurements below.

Planet	Type	Radius (R⊕)	Mass (M⊕)	Period (d)	Eq. T (K)	Year
Kepler-338 e this	Super-Earth	1.56	8.50	9.341	1,143	2014
Kepler-338 b	Sub-Neptune	2.44	30.60	13.727	1,005	2014
Kepler-338 c	Sub-Neptune	2.34	6.08	24.311	831	2014
Kepler-338 d	Sub-Neptune	3.00	9.27	44.431	680	2014

Kepler-338 e Planet Profile

Physical Specs

Radius

1.56 R⊕

Radius (Jupiter)

0.139 R♃

Mass

8.50 M⊕

Mass (Jupiter)

0.027 M♃

Density

12.30 g/cm³

Surface Gravity

3.49 g (Earth)

Classification

Planet Type

Super-Earth

ESI Score 0.218

HZ Position Inner

Controversial No

Discovery

Year 2014

Method Transit Timing Variations

Facility Kepler

Telescope 0.95 m Kepler Telescope

Size rank in cohort

Rank by radius

#636of 1176

top 54.0%

This planet

1.56R⊕

Super-Earth median

1.60R⊕

Nearest-size peers

Kepler-402 c 1.56 R⊕ Kepler-309 b 1.56 R⊕ Kepler-49 e 1.56 R⊕

Metric	Earth	Kepler-338 e	Jupiter
Radius (R⊕)	1.00	1.56	11.21
Mass (M⊕)	1.00	8.50	317.83
Density (g/cm³)	5.51	12.30	1.33
Surface Gravity (g)	1.00	3.49	2.53
Insolation (S⊕)	1.00	428.52	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Best measured mass	8.500 M⊕	Direct mass measurement (not derived).

Star Catalogue Identifiers

TIC

TIC 258203303

Gaia DR2

Gaia DR2 2104344141784539264

Gaia DR3

Gaia DR3 2104344141784539264

System

Kepler-338

Percentile among Super-Earth cohort

Radius 1.560 R⊕ · percentile 45 / cohort 1176

Mass 8.500 M⊕ · percentile 96 / cohort 1176

Orbital period 9.34 d · percentile 63 / cohort 1164

Distance 552.80 pc · percentile 50 / cohort 1171

ESI 0.218 · percentile 16 / cohort 1176

Orbit & Habitability

Orbital Dynamics

Period

9.341 days

Semi-major axis

0.0898 AU

Eccentricity

0.050

Inclination

87.49 °

Year Length

A year here lasts approximately 9.34 Earth days (2.6% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0898 AU.

Transit Fingerprint

Depth

0.008 %

Duration

6.180 h

Impact parameter b

0.690

Rp / R★

0.008438

Transit midpoint (BJD)

2,454,965.3858

Photometric dip

Transit produces a flux drop of 82 ppm lasting ≈ 6.18 h.

Extended Orbital Architecture

Planet / star radius ratio

0.008438

Semi-major axis / stellar radius

8.890

Impact parameter (b)

0.690

Transit mid-time (BJD)

2,454,965.3858

Angular separation (arcsec)

0.16200

Eq. Temperature

1,143K

(870 °C)

Insolation (S⊕)

428.52

Earth = 1.00

Earth Similarity (ESI)

0.218

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.

Transit timing variations

Gravitational interactions from neighbours have been detected.

Discovery Paper

Primary reference

Hadden et al. 2014

Instrument

Kepler CCD Array

Publication

2014-05

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-338

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,999 K — hotter than the Sun (5,778 K)

Estimated Age

6.46 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

1.735 R☉

Stellar Mass

1.140 M☉

Metallicity [Fe/H]

-0.03

Extended Stellar Properties

Surface gravity (log g)

4.020 dex

Stellar density

0.210 g/cm³

Systemic radial velocity

-15.36 km/s

Metallicity ratio

[M/H]

Distance

552.80 parsec

Light-years 1,802.98 ly

V-band magnitude

12.19 mag

Voyager-speed travel 31,795,618 yr

Multi-band Host Photometry — 17 bands

Astrometric Data

Parallax

1.780 mas

Total Proper Motion

22.197 mas/yr

PM Right Ascension

16.22 mas/yr

PM Declination

15.15 mas/yr

Galactic Cartesian (pc)

x = 0.170 · y = -0.738 · z = 0.653

Equatorial (J2000)

RA 282.97906° · Dec 40.78442°

Galactic ℓ, b

70.483° · 17.244°

Ecliptic λ, β

292.177° · 63.228°

HTM-20 index

-861789349