Key parameters at a glance
- A radius of 2.21 Earth radii
- A mass of 4.44 Earth masses
- Surface gravity around 0.91 g
- An orbital period of 15.270 days
- Semi-major axis 0.1201 AU
- Equilibrium temperature 896 K (623 °C)
- Distance from Earth 2,725.87 light-years
- Earth Similarity Index 0.286
- Travel time at Voyager 1 speed 48,070,685 years
2 siblings around Kepler-23
Kepler-23 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-23 b | Super-Earth | 1.64 | 2.56 | 7.100 | 1,157 | 2011 |
| Kepler-23 c | Sub-Neptune | 3.01 | 7.81 | 10.740 | 1,008 | 2011 |
| Kepler-23 d this | Sub-Neptune | 2.21 | 4.44 | 15.270 | 896 | 2014 |
Kepler-23 d Planet Profile
Physical Specs
Classification
Planet Type
Sub-Neptune
Discovery
Size rank in cohort
Rank by radius
#1671of 1978
top 84.4%
This planet
2.21R⊕
Sub-Neptune median
2.71R⊕
Nearest-size peers
| Metric | Earth | Kepler-23 d | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 2.21 | 11.21 |
| Mass (M⊕) | 1.00 | 4.44 | 317.83 |
| Density (g/cm³) | 5.51 | 2.26 | 1.33 |
| Surface Gravity (g) | 1.00 | 0.91 | 2.53 |
| Insolation (S⊕) | 1.00 | 161.04 | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Best measured mass | 4.440 M⊕ | Direct mass measurement (not derived). |
Star Catalogue Identifiers
TIC
TIC 27083727
Gaia DR2
Gaia DR2 2135019107451751168
Gaia DR3
Gaia DR3 2135019107451751168
System
Kepler-23
Percentile among Sub-Neptune cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 15.27 Earth days (4.2% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.1201 AU.
Transit Fingerprint
Depth
0.021 %
Duration
6.077 h
Impact parameter b
0.241
Rp / R★
0.013073
Transit midpoint (BJD)
2,454,980.5811
Photometric dip
Transit produces a flux drop of 207 ppm lasting ≈ 6.08 h.
Extended Orbital Architecture
Planet / star radius ratio
0.013073
Semi-major axis / stellar radius
19.240
Impact parameter (b)
0.241
Transit mid-time (BJD)
2,454,980.5811
Angular separation (arcsec)
0.14400
Eq. Temperature
896K
(623 °C)
Insolation (S⊕)
161.04
Earth = 1.00
Earth Similarity (ESI)
0.286
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-23
Spectral Class
G-type yellow (Sun-like)
Effective Temperature
5,828 K — hotter than the Sun (5,778 K)
Estimated Age
9.12 Gyr — older than the Sun (4.6 Gyr)
Stellar Radius
1.548 R☉
Stellar Mass
1.078 M☉
Metallicity [Fe/H]
-0.11
Extended Stellar Properties
Surface gravity (log g)
4.090 dex
Stellar density
0.410 g/cm³
Metallicity ratio
[M/H]
Multi-band Host Photometry — 16 bands
Astrometric Data
Parallax
1.168 mas
Total Proper Motion
4.466 mas/yr
PM Right Ascension
2.26 mas/yr
PM Declination
3.85 mas/yr
Galactic Cartesian (pc)
x = 0.267 · y = -0.593 · z = 0.760
Equatorial (J2000)
RA 294.21891° · Dec 49.47925°
Galactic ℓ, b
82.014° · 13.458°
Ecliptic λ, β
317.845° · 68.930°
HTM-20 index
275671563
Similar Worlds
Kepler-1861 b
Sub-Neptune · G-type yellow (Sun-like)
Radius 2.21 R⊕ · 2,707.0 ly
Kepler-19 b
Sub-Neptune · G-type yellow (Sun-like)
Radius 2.21 R⊕ · 712.9 ly
Kepler-1862 b
Sub-Neptune · G-type yellow (Sun-like)
Radius 2.20 R⊕ · 4,018.9 ly
Kepler-632 b
Sub-Neptune · G-type yellow (Sun-like)
Radius 2.21 R⊕ · 1,138.3 ly
Kepler-862 b
Sub-Neptune · G-type yellow (Sun-like)
Radius 2.21 R⊕ · 3,388.9 ly
Kepler-110 c
Sub-Neptune · G-type yellow (Sun-like)
Radius 2.21 R⊕ · 1,913.0 ly