Key parameters at a glance
- A radius of 3.69 Earth radii
- A mass of 13.20 Earth masses
- Surface gravity around 0.97 g
- An orbital period of 28.082 days
- Semi-major axis 0.1800 AU
- Equilibrium temperature 522 K (249 °C)
- Distance from Earth 2,475.05 light-years
- Earth Similarity Index 0.408
- Travel time at Voyager 1 speed 43,647,466 years
2 siblings around Kepler-222
Kepler-222 d 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-222 b | Sub-Neptune | 3.16 | 10.10 | 3.937 | 1,004 | 2014 |
| Kepler-222 c | Neptune-like | 4.64 | 19.40 | 10.089 | 734 | 2014 |
| Kepler-222 d this | Sub-Neptune | 3.69 | 13.20 | 28.082 | 522 | 2014 |
Kepler-222 d Planet Profile
Physical Specs
Classification
Planet Type
Sub-Neptune
Discovery
Size rank in cohort
Rank by radius
#92of 1978
top 4.6%
This planet
3.69R⊕
Sub-Neptune median
2.71R⊕
Nearest-size peers
| Metric | Earth | Kepler-222 d | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 3.69 | 11.21 |
| Mass (M⊕) | 1.00 | 13.20 | 317.83 |
| Density (g/cm³) | 5.51 | 1.44 | 1.33 |
| Surface Gravity (g) | 1.00 | 0.97 | 2.53 |
| Insolation (S⊕) | 1.00 | 15.09 | 0.037 |
Star Catalogue Identifiers
TIC
TIC 158625100
Gaia DR2
Gaia DR2 2130460394803778816
Gaia DR3
Gaia DR3 2130460394803778816
System
Kepler-222
Percentile among Sub-Neptune cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 28.08 Earth days (7.7% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.1800 AU.
Transit Fingerprint
Depth
0.202 %
Duration
4.541 h
Impact parameter b
0.440
Rp / R★
0.040725
Transit midpoint (BJD)
2,455,027.9140
Photometric dip
Transit produces a flux drop of 2,017 ppm lasting ≈ 4.54 h.
Extended Orbital Architecture
Planet / star radius ratio
0.040725
Semi-major axis / stellar radius
47.380
Impact parameter (b)
0.440
Transit mid-time (BJD)
2,455,027.9140
Angular separation (arcsec)
0.23700
Eq. Temperature
522K
(249 °C)
Insolation (S⊕)
15.09
Earth = 1.00
Earth Similarity (ESI)
0.408
0 = alien, 1 = Earth-identical
Inside the inner HZ boundary (too hot for liquid water) — the surface is too hot to retain surface water.
Detection Signatures
Transit photometry
A transit dip has been observed from at least one telescope.
Transit timing variations
Gravitational interactions from neighbours have been detected.
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-222
Spectral Class
G-type yellow (Sun-like)
Effective Temperature
5,433 K — cooler than the Sun (5,778 K)
Estimated Age
1.17 Gyr — younger than the Sun (4.6 Gyr)
Stellar Radius
0.869 R☉
Stellar Mass
0.933 M☉
Metallicity [Fe/H]
0.33
Extended Stellar Properties
Surface gravity (log g)
4.551 dex
Stellar density
1.570 g/cm³
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 16 bands
Astrometric Data
Parallax
1.289 mas
Total Proper Motion
1.139 mas/yr
PM Right Ascension
0.60 mas/yr
PM Declination
-0.97 mas/yr
Galactic Cartesian (pc)
x = 0.210 · y = -0.650 · z = 0.731
Equatorial (J2000)
RA 287.90609° · Dec 46.93775°
Galactic ℓ, b
77.826° · 16.242°
Ecliptic λ, β
304.493° · 68.243°
HTM-20 index
-1645614768
Similar Worlds
Kepler-150 c
Sub-Neptune · G-type yellow (Sun-like)
Radius 3.69 R⊕ · 2,906.4 ly
Kepler-1627 b
Sub-Neptune · G-type yellow (Sun-like)
Radius 3.69 R⊕ · 1,035.3 ly
Kepler-19 c
Sub-Neptune · G-type yellow (Sun-like)
Radius 3.68 R⊕ · 712.9 ly
Kepler-1016 c
Sub-Neptune · G-type yellow (Sun-like)
Radius 3.68 R⊕ · 4,575.4 ly
Kepler-582 b
Sub-Neptune · G-type yellow (Sun-like)
Radius 3.68 R⊕ · 1,999.9 ly
Kepler-698 b
Sub-Neptune · G-type yellow (Sun-like)
Radius 3.68 R⊕ · 6,508.7 ly