Key parameters at a glance

A radius of 2.23 Earth radii
A mass of 5.60 Earth masses
Surface gravity around 1.13 g
An orbital period of 5.375 days
Semi-major axis 0.0650 AU
Equilibrium temperature 1,413 K (1140 °C)
Distance from Earth 3,602.85 light-years
Earth Similarity Index 0.177
Travel time at Voyager 1 speed 63,536,250 years

2 siblings around Kepler-217

Kepler-217 b shares its host star with 2 other confirmed planets. Side-by-side measurements below.

Planet	Type	Radius (R⊕)	Mass (M⊕)	Period (d)	Eq. T (K)	Year
Kepler-217 d	Super-Earth	1.32	2.30	3.887	1,574	2016
Kepler-217 b this	Sub-Neptune	2.23	5.60	5.375	1,413	2014
Kepler-217 c	Super-Earth	1.85	4.08	8.586	1,208	2014

Kepler-217 b Planet Profile

Physical Specs

Radius

2.23 R⊕

Radius (Jupiter)

0.199 R♃

Mass

5.60 M⊕

Mass (Jupiter)

0.018 M♃

Density

2.77 g/cm³

Surface Gravity

1.13 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.177

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

#1622of 1978

top 82.0%

This planet

2.23R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

Kepler-292 d 2.23 R⊕ Kepler-165 c 2.23 R⊕ Kepler-235 b 2.23 R⊕

Metric	Earth	Kepler-217 b	Jupiter
Radius (R⊕)	1.00	2.23	11.21
Mass (M⊕)	1.00	5.60	317.83
Density (g/cm³)	5.51	2.77	1.33
Surface Gravity (g)	1.00	1.13	2.53
Insolation (S⊕)	1.00	1,366.48	0.037

Star Catalogue Identifiers

TIC

TIC 240178935

Gaia DR2

Gaia DR2 2128268380936413568

Gaia DR3

Gaia DR3 2128268380936413568

System

Kepler-217

Percentile among Sub-Neptune cohort

Radius 2.230 R⊕ · percentile 17 / cohort 1978

Mass 5.600 M⊕ · percentile 17 / cohort 1978

Orbital period 5.37 d · percentile 14 / cohort 1946

Distance 1,104.64 pc · percentile 84 / cohort 1975

ESI 0.177 · percentile 4 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period

5.375 days

Semi-major axis

0.0650 AU

Eccentricity

0.000

Inclination

88.73 °

Year Length

A year here lasts approximately 5.37 Earth days (1.5% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0650 AU.

Transit Fingerprint

Depth

0.015 %

Duration

4.011 h

Impact parameter b

0.020

Rp / R★

0.011491

Transit midpoint (BJD)

2,455,003.9332

Photometric dip

Transit produces a flux drop of 154 ppm lasting ≈ 4.01 h.

Extended Orbital Architecture

Planet / star radius ratio

0.011491

Semi-major axis / stellar radius

5.460

Impact parameter (b)

0.020

Transit mid-time (BJD)

2,455,003.9332

Angular separation (arcsec)

0.05880

Eq. Temperature

1,413K

(1140 °C)

Insolation (S⊕)

1,366.48

Earth = 1.00

Earth Similarity (ESI)

0.177

0 = alien, 1 = Earth-identical

Inside the inner HZ boundary (too hot for liquid water) — the dayside is scorched.

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-217

Spectral Class

F-type yellow-white

Effective Temperature

6,171 K — hotter than the Sun (5,778 K)

Estimated Age

2.40 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

1.799 R☉

Stellar Mass

1.342 M☉

Metallicity [Fe/H]

-0.07

Extended Stellar Properties

Surface gravity (log g)

4.030 dex

Stellar density

0.250 g/cm³

Metallicity ratio

[Fe/H]

Distance

1,104.64 parsec

Light-years 3,602.85 ly

V-band magnitude

13.16 mag

Voyager-speed travel 63,536,250 yr

Multi-band Host Photometry — 15 bands

Astrometric Data

Parallax

0.876 mas

Total Proper Motion

1.992 mas/yr

PM Right Ascension

-1.80 mas/yr

PM Declination

0.84 mas/yr

Galactic Cartesian (pc)

x = 0.270 · y = -0.636 · z = 0.723

Equatorial (J2000)

RA 293.03773° · Dec 46.27752°

Galactic ℓ, b

78.704° · 12.758°

Ecliptic λ, β

312.408° · 66.357°

HTM-20 index

-1442853971