Key parameters at a glance

A radius of 4.30 Earth radii
A mass of 122.00 Earth masses
Surface gravity around 6.60 g
An orbital period of 105.599 days
Semi-major axis 0.4632 AU
Equilibrium temperature 475 K (202 °C)
Distance from Earth 3,831.00 light-years
Earth Similarity Index 0.377
Travel time at Voyager 1 speed 67,559,606 years

brightness_6

Circumbinary planet

Kepler-38 b orbits a binary-star pair rather than a single host — a minority architecture in the confirmed catalogue.

Kepler-38 b Planet Profile

Physical Specs

Radius

4.30 R⊕

Radius (Jupiter)

0.384 R♃

Mass

122.00 M⊕

Mass (Jupiter)

0.384 M♃

Density

— g/cm³

Surface Gravity

6.60 g (Earth)

Classification

Planet Type

Neptune-like

ESI Score 0.377

HZ Position Unknown

Controversial No

Discovery

Year 2012

Method Transit

Facility Kepler

Telescope 0.95 m Kepler Telescope

Size rank in cohort

Rank by radius

#494of 574

top 85.9%

This planet

4.30R⊕

Neptune-like median

6.39R⊕

Nearest-size peers

Kepler-359 c 4.30 R⊕ Kepler-279 c 4.30 R⊕ KOI-984 b 4.30 R⊕

Metric	Earth	Kepler-38 b	Jupiter
Radius (R⊕)	1.00	4.30	11.21
Mass (M⊕)	1.00	122.00	317.83
Density (g/cm³)	5.51	—	1.33
Surface Gravity (g)	1.00	6.60	2.53
Insolation (S⊕)	1.00	—	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Best measured mass	122.000 M⊕	Direct mass measurement (not derived).

Star Catalogue Identifiers

TIC

TIC 158316612

Gaia DR2

Gaia DR2 2105448841733970432

Gaia DR3

Gaia DR3 2105448841733970432

System

Kepler-38

Percentile among Neptune-like cohort

Radius 4.300 R⊕ · percentile 13 / cohort 574

Mass 122.000 M⊕ · percentile 93 / cohort 574

Orbital period 105.60 d · percentile 83 / cohort 524

Distance 1,174.59 pc · percentile 78 / cohort 572

ESI 0.377 · percentile 69 / cohort 574

Orbit & Habitability

Orbital Dynamics

Period

105.599 days

Semi-major axis

0.4632 AU

Eccentricity

0.032

Inclination

89.44 °

Year Length

A year here lasts approximately 105.60 Earth days (28.9% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.4632 AU.

Transit Fingerprint

Depth

0.050 %

Rp / R★

0.022540

Transit midpoint (BJD)

2,454,932.1040

Photometric dip

Transit produces a flux drop of 500 ppm.

Eq. Temperature

475K

(202 °C)

Insolation (S⊕)

—

Earth = 1.00

Earth Similarity (ESI)

0.377

0 = alien, 1 = Earth-identical

Insufficient insolation data — the surface is too hot to retain surface water.

Discovery Paper

Primary reference

Orosz et al. 2012

Instrument

Kepler CCD Array

Publication

2012-10

Observation locale

Space

Discovery cohort

Planets confirmed in 2012 at Kepler (12 shown).

Kepler-54 c · Rocky Terrestrial Kepler-49 c · Sub-Neptune Kepler-55 b · Sub-Neptune Kepler-49 b · Sub-Neptune Kepler-81 c · Sub-Neptune Kepler-55 c · Sub-Neptune Kepler-52 c · Super-Earth Kepler-83 c · Sub-Neptune Kepler-32 d · Sub-Neptune Kepler-83 b · Sub-Neptune Kepler-54 b · Sub-Neptune Kepler-80 c · Sub-Neptune

Host System: Kepler-38

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,623 K — cooler than the Sun (5,778 K)

Estimated Age

10.00 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

1.752 R☉

Stellar Mass

0.941 M☉

Metallicity [Fe/H]

-0.11

Extended Stellar Properties

Surface gravity (log g)

3.926 dex

Stellar density

0.175 g/cm³

Rotational v·sin i

2.40 km/s

Metallicity ratio

[M/H]

Distance

1,174.59 parsec

Light-years 3,831.00 ly

V-band magnitude

14.02 mag

Voyager-speed travel 67,559,606 yr

Multi-band Host Photometry — 16 bands

Astrometric Data

Parallax

0.823 mas

Total Proper Motion

13.956 mas/yr

PM Right Ascension

-4.65 mas/yr

PM Declination

-13.16 mas/yr

Galactic Cartesian (pc)

x = 0.214 · y = -0.708 · z = 0.673

Equatorial (J2000)

RA 286.83031° · Dec 42.27914°

Galactic ℓ, b

73.057° · 15.139°

Ecliptic λ, β

299.270° · 64.018°

HTM-20 index

-2040173498