Key parameters at a glance
- A radius of 3.85 Earth radii
- A mass of 14.20 Earth masses
- Surface gravity around 0.96 g
- An orbital period of 41.195 days
- Semi-major axis 0.2200 AU
- Equilibrium temperature 439 K (166 °C)
- Distance from Earth 2,694.91 light-years
- Earth Similarity Index 0.466
- Travel time at Voyager 1 speed 47,524,786 years
- Almost certainly tidally locked to its host star given the close orbit
2 siblings around Kepler-229
Kepler-229 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-229 b | Sub-Neptune | 2.20 | 5.48 | 6.253 | 823 | 2014 |
| Kepler-229 c | Neptune-like | 4.92 | 21.50 | 16.069 | 600 | 2014 |
| Kepler-229 d this | Sub-Neptune | 3.85 | 14.20 | 41.195 | 439 | 2014 |
Kepler-229 d Planet Profile
Physical Specs
Classification
Planet Type
Sub-Neptune
Discovery
Size rank in cohort
Rank by radius
#44of 1978
top 2.2%
This planet
3.85R⊕
Sub-Neptune median
2.71R⊕
Nearest-size peers
| Metric | Earth | Kepler-229 d | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 3.85 | 11.21 |
| Mass (M⊕) | 1.00 | 14.20 | 317.83 |
| Density (g/cm³) | 5.51 | 1.37 | 1.33 |
| Surface Gravity (g) | 1.00 | 0.96 | 2.53 |
| Insolation (S⊕) | 1.00 | 6.16 | 0.037 |
Star Catalogue Identifiers
TIC
TIC 399912169
Gaia DR2
Gaia DR2 2131114947819394816
Gaia DR3
Gaia DR3 2131114947819394816
System
Kepler-229
Percentile among Sub-Neptune cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 41.19 Earth days (11.3% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.2200 AU.
Transit Fingerprint
Depth
0.221 %
Duration
5.020 h
Impact parameter b
0.800
Rp / R★
0.041693
Transit midpoint (BJD)
2,454,998.0237
Photometric dip
Transit produces a flux drop of 2,214 ppm lasting ≈ 5.02 h.
Extended Orbital Architecture
Planet / star radius ratio
0.041693
Semi-major axis / stellar radius
70.750
Impact parameter (b)
0.800
Transit mid-time (BJD)
2,454,998.0237
Angular separation (arcsec)
0.26600
Eq. Temperature
439K
(166 °C)
Insolation (S⊕)
6.16
Earth = 1.00
Earth Similarity (ESI)
0.466
0 = alien, 1 = Earth-identical
Inside the inner HZ boundary (too hot for liquid water) — the surface is too hot to retain surface water. Close-orbiting tidally-locked around a cool host.
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-229
Spectral Class
K-type orange
Effective Temperature
5,120 K — cooler than the Sun (5,778 K)
Estimated Age
2.04 Gyr — younger than the Sun (4.6 Gyr)
Stellar Radius
0.728 R☉
Stellar Mass
0.808 M☉
Metallicity [Fe/H]
0.06
Extended Stellar Properties
Surface gravity (log g)
4.633 dex
Stellar density
1.940 g/cm³
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 16 bands
Astrometric Data
Parallax
1.182 mas
Total Proper Motion
5.627 mas/yr
PM Right Ascension
-1.33 mas/yr
PM Declination
-5.47 mas/yr
Galactic Cartesian (pc)
x = 0.194 · y = -0.635 · z = 0.748
Equatorial (J2000)
RA 286.99948° · Dec 48.37579°
Galactic ℓ, b
78.978° · 17.348°
Ecliptic λ, β
304.224° · 69.803°
HTM-20 index
-565252898
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