Key parameters at a glance
- A radius of 2.70 Earth radii
- A mass of 7.75 Earth masses
- Surface gravity around 1.06 g
- An orbital period of 4.134 days
- Semi-major axis 0.0520 AU
- Equilibrium temperature 1,160 K (887 °C)
- Distance from Earth 5,363.99 light-years
- Earth Similarity Index 0.206
- Travel time at Voyager 1 speed 94,594,032 years
2 siblings around Kepler-228
Kepler-228 c 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 | Super-Earth | 1.53 | 2.96 | 2.567 | 1,360 | 2014 |
| Kepler-228 c this | 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 c Planet Profile
Physical Specs
Classification
Planet Type
Sub-Neptune
Discovery
Size rank in cohort
Rank by radius
#865of 1978
top 43.7%
This planet
2.70R⊕
Sub-Neptune median
2.71R⊕
Nearest-size peers
| Metric | Earth | Kepler-228 c | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 2.70 | 11.21 |
| Mass (M⊕) | 1.00 | 7.75 | 317.83 |
| Density (g/cm³) | 5.51 | 2.16 | 1.33 |
| Surface Gravity (g) | 1.00 | 1.06 | 2.53 |
| Insolation (S⊕) | 1.00 | 457.32 | 0.037 |
Star Catalogue Identifiers
TIC
TIC 27772524
Gaia DR2
Gaia DR2 2086660283961964416
Gaia DR3
Gaia DR3 2086660283961964416
System
Kepler-228
Percentile among Sub-Neptune cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 4.13 Earth days (1.1% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0520 AU.
Transit Fingerprint
Depth
0.069 %
Duration
3.123 h
Impact parameter b
0.150
Rp / R★
0.027630
Transit midpoint (BJD)
2,455,005.9768
Photometric dip
Transit produces a flux drop of 686 ppm lasting ≈ 3.12 h.
Extended Orbital Architecture
Planet / star radius ratio
0.027630
Semi-major axis / stellar radius
5.660
Impact parameter (b)
0.150
Transit mid-time (BJD)
2,455,005.9768
Angular separation (arcsec)
0.03160
Eq. Temperature
1,160K
(887 °C)
Insolation (S⊕)
457.32
Earth = 1.00
Earth Similarity (ESI)
0.206
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. 2014Instrument
Kepler CCD Array
Publication
2014-03
Observation locale
Space
Discovery cohort
Planets confirmed in 2014 at Kepler (12 shown).
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]
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
Similar Worlds
Kepler-1452 b
Sub-Neptune · F-type yellow-white
Radius 2.70 R⊕ · 3,249.6 ly
Kepler-1677 b
Sub-Neptune · F-type yellow-white
Radius 2.70 R⊕ · 2,398.5 ly
Kepler-1807 b
Sub-Neptune · F-type yellow-white
Radius 2.70 R⊕ · 4,237.8 ly
Kepler-168 c
Sub-Neptune · F-type yellow-white
Radius 2.69 R⊕ · 4,382.2 ly
HD 28109 b
Sub-Neptune · F-type yellow-white
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Kepler-1543 b
Sub-Neptune · F-type yellow-white
Radius 2.71 R⊕ · 3,006.5 ly