Key parameters at a glance

A radius of 2.46 Earth radii
A mass of 6.62 Earth masses
Surface gravity around 1.09 g
An orbital period of 22.251 days
Semi-major axis 0.1440 AU
Equilibrium temperature 539 K (266 °C)
Distance from Earth 3,160.45 light-years
Earth Similarity Index 0.467
Travel time at Voyager 1 speed 55,734,562 years

1 sibling around Kepler-397

Kepler-397 b 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-397 b this	Sub-Neptune	2.46	6.62	22.251	539	2014
Kepler-397 c	Neptune-like	6.18	31.60	135.499	295	2014

Kepler-397 b Planet Profile

Physical Specs

Radius

2.46 R⊕

Radius (Jupiter)

0.219 R♃

Mass

6.62 M⊕

Mass (Jupiter)

0.021 M♃

Density

2.44 g/cm³

Surface Gravity

1.09 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.467

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

#1245of 1978

top 62.9%

This planet

2.46R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

TOI-5800 b 2.46 R⊕ Kepler-282 d 2.46 R⊕ GJ 3341 b 2.46 R⊕

Metric	Earth	Kepler-397 b	Jupiter
Radius (R⊕)	1.00	2.46	11.21
Mass (M⊕)	1.00	6.62	317.83
Density (g/cm³)	5.51	2.44	1.33
Surface Gravity (g)	1.00	1.09	2.53
Insolation (S⊕)	1.00	20.01	0.037

Star Catalogue Identifiers

TIC

TIC 271963778

System

Kepler-397

Percentile among Sub-Neptune cohort

Radius 2.460 R⊕ · percentile 37 / cohort 1978

Mass 6.620 M⊕ · percentile 35 / cohort 1978

Orbital period 22.25 d · percentile 66 / cohort 1946

Distance 969.00 pc · percentile 76 / cohort 1975

ESI 0.467 · percentile 65 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period

22.251 days

Semi-major axis

0.1440 AU

Eccentricity

0.000

Inclination

89.33 °

Year Length

A year here lasts approximately 22.25 Earth days (6.1% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.1440 AU.

Transit Fingerprint

Depth

0.062 %

Duration

1.689 h

Impact parameter b

0.940

Rp / R★

0.023850

Transit midpoint (BJD)

2,454,982.4307

Photometric dip

Transit produces a flux drop of 619 ppm lasting ≈ 1.69 h.

Extended Orbital Architecture

Planet / star radius ratio

0.023850

Semi-major axis / stellar radius

44.000

Impact parameter (b)

0.940

Transit mid-time (BJD)

2,454,982.4307

Angular separation (arcsec)

0.14900

Eq. Temperature

539K

(266 °C)

Insolation (S⊕)

20.01

Earth = 1.00

Earth Similarity (ESI)

0.467

0 = alien, 1 = Earth-identical

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

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-397

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,307 K — cooler than the Sun (5,778 K)

Estimated Age

5.25 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

0.767 R☉

Stellar Mass

0.844 M☉

Metallicity [Fe/H]

-0.24

Extended Stellar Properties

Surface gravity (log g)

4.572 dex

Stellar density

1.317 g/cm³

Metallicity ratio

[Fe/H]

Distance

969.00 parsec

Light-years 3,160.45 ly

V-band magnitude

16.36 mag

Voyager-speed travel 55,734,562 yr

Multi-band Host Photometry — 15 bands

Astrometric Data

Total Proper Motion

5.179 mas/yr

PM Right Ascension

-5.12 mas/yr

PM Declination

-0.77 mas/yr

Galactic Cartesian (pc)

x = 0.323 · y = -0.665 · z = 0.674

Equatorial (J2000)

RA 295.89404° · Dec 42.38052°

Galactic ℓ, b

76.135° · 9.154°

Ecliptic λ, β

313.360° · 61.977°

HTM-20 index

-1603995579