Key parameters at a glance

A radius of 1.53 Earth radii
A mass of 2.96 Earth masses
Surface gravity around 1.26 g
An orbital period of 2.567 days
Semi-major axis 0.0380 AU
Equilibrium temperature 1,360 K (1087 °C)
Distance from Earth 5,363.99 light-years
Earth Similarity Index 0.210
Travel time at Voyager 1 speed 94,594,032 years

2 siblings around Kepler-228

Kepler-228 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-228 b this	Super-Earth	1.53	2.96	2.567	1,360	2014
Kepler-228 c	Sub-Neptune	2.70	7.75	4.134	1,160	2014
Kepler-228 d	Neptune-like	4.04	15.40	11.094	835	2014

Kepler-228 b Planet Profile

Physical Specs

Radius

1.53 R⊕

Radius (Jupiter)

0.136 R♃

Mass

2.96 M⊕

Mass (Jupiter)

0.009 M♃

Density

4.54 g/cm³

Surface Gravity

1.26 g (Earth)

Classification

Planet Type

Super-Earth

ESI Score 0.210

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

#687of 1176

top 58.3%

This planet

1.53R⊕

Super-Earth median

1.60R⊕

Nearest-size peers

Kepler-296 e 1.53 R⊕ Kepler-147 b 1.53 R⊕ Kepler-54 d 1.53 R⊕

Metric	Earth	Kepler-228 b	Jupiter
Radius (R⊕)	1.00	1.53	11.21
Mass (M⊕)	1.00	2.96	317.83
Density (g/cm³)	5.51	4.54	1.33
Surface Gravity (g)	1.00	1.26	2.53
Insolation (S⊕)	1.00	863.78	0.037

Star Catalogue Identifiers

TIC

TIC 27772524

Gaia DR2

Gaia DR2 2086660283961964416

Gaia DR3

Gaia DR3 2086660283961964416

System

Kepler-228

Percentile among Super-Earth cohort

Radius 1.530 R⊕ · percentile 40 / cohort 1176

Mass 2.960 M⊕ · percentile 37 / cohort 1176

Orbital period 2.57 d · percentile 17 / cohort 1164

Distance 1,644.61 pc · percentile 96 / cohort 1171

ESI 0.210 · percentile 15 / cohort 1176

Orbit & Habitability

Orbital Dynamics

Period

2.567 days

Semi-major axis

0.0380 AU

Eccentricity

0.000

Inclination

82.17 °

Year Length

A year here lasts approximately 2.57 Earth days (0.7% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0380 AU.

Transit Fingerprint

Depth

0.023 %

Duration

2.327 h

Impact parameter b

0.450

Rp / R★

0.014685

Transit midpoint (BJD)

2,455,012.5536

Photometric dip

Transit produces a flux drop of 227 ppm lasting ≈ 2.33 h.

Extended Orbital Architecture

Planet / star radius ratio

0.014685

Semi-major axis / stellar radius

4.120

Impact parameter (b)

0.450

Transit mid-time (BJD)

2,455,012.5536

Angular separation (arcsec)

0.02310

Eq. Temperature

1,360K

(1087 °C)

Insolation (S⊕)

863.78

Earth = 1.00

Earth Similarity (ESI)

0.210

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-228

Spectral Class

F-type yellow-white

Effective Temperature

6,043 K — hotter than the Sun (5,778 K)

Estimated Age

6.76 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

1.014 R☉

Stellar Mass

1.006 M☉

Metallicity [Fe/H]

0.18

Extended Stellar Properties

Surface gravity (log g)

4.467 dex

Stellar density

0.790 g/cm³

Metallicity ratio

[Fe/H]

Distance

1,644.61 parsec

Light-years 5,363.99 ly

V-band magnitude

15.90 mag

Voyager-speed travel 94,594,032 yr

Multi-band Host Photometry — 16 bands

Astrometric Data

Parallax

0.580 mas

Total Proper Motion

9.434 mas/yr

PM Right Ascension

-5.05 mas/yr

PM Declination

-7.97 mas/yr

Galactic Cartesian (pc)

x = 0.295 · y = -0.597 · z = 0.746

Equatorial (J2000)

RA 296.28609° · Dec 48.22463°

Galactic ℓ, b

81.503° · 11.676°

Ecliptic λ, β

319.563° · 67.194°

HTM-20 index

1987710185