Key parameters at a glance
- A radius of 3.07 Earth radii
- A mass of 23.10 Earth masses
- Surface gravity around 2.45 g
- An orbital period of 13.234 days
- Semi-major axis 0.1150 AU
- Equilibrium temperature 888 K (615 °C)
- Distance from Earth 5,866.73 light-years
- Earth Similarity Index 0.272
- Travel time at Voyager 1 speed 103,459,796 years
4 siblings around Kepler-238
Kepler-238 d shares its host star with 4 other confirmed planets. Side-by-side measurements below.
| Planet | Type | Radius (R⊕) | Mass (M⊕) | Period (d) | Eq. T (K) | Year |
|---|---|---|---|---|---|---|
| Kepler-238 b | Super-Earth | 1.73 | 3,305.02 | 2.091 | 1,642 | 2014 |
| Kepler-238 c | Sub-Neptune | 2.39 | 152.52 | 6.156 | 1,146 | 2014 |
| Kepler-238 d this | Sub-Neptune | 3.07 | 23.10 | 13.234 | 888 | 2014 |
| Kepler-238 e | Neptune-like | 5.60 | 169.70 | 23.654 | 731 | 2013 |
| Kepler-238 f | Sub-Neptune | 2.00 | 13.50 | 50.447 | 568 | 2013 |
Kepler-238 d Planet Profile
Physical Specs
Classification
Planet Type
Sub-Neptune
Discovery
Size rank in cohort
Rank by radius
#456of 1978
top 23.0%
This planet
3.07R⊕
Sub-Neptune median
2.71R⊕
Nearest-size peers
| Metric | Earth | Kepler-238 d | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 3.07 | 11.21 |
| Mass (M⊕) | 1.00 | 23.10 | 317.83 |
| Density (g/cm³) | 5.51 | 2.95 | 1.33 |
| Surface Gravity (g) | 1.00 | 2.45 | 2.53 |
| Insolation (S⊕) | 1.00 | 213.48 | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Best measured mass | 23.100 M⊕ | Direct mass measurement (not derived). |
Star Catalogue Identifiers
TIC
TIC 121460918
Gaia DR2
Gaia DR2 2100624562669914240
Gaia DR3
Gaia DR3 2100624562669914240
System
Kepler-238
Percentile among Sub-Neptune cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 13.23 Earth days (3.6% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.1150 AU.
Transit Fingerprint
Depth
0.050 %
Duration
6.642 h
Impact parameter b
0.430
Rp / R★
0.020278
Transit midpoint (BJD)
2,454,973.3218
Photometric dip
Transit produces a flux drop of 505 ppm lasting ≈ 6.64 h.
Extended Orbital Architecture
Planet / star radius ratio
0.020278
Semi-major axis / stellar radius
9.460
Impact parameter (b)
0.430
Transit mid-time (BJD)
2,454,973.3218
Angular separation (arcsec)
0.06390
Eq. Temperature
888K
(615 °C)
Insolation (S⊕)
213.48
Earth = 1.00
Earth Similarity (ESI)
0.272
0 = alien, 1 = Earth-identical
Inside the inner HZ boundary (too hot for liquid water) — the surface is too hot to retain surface water.
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-238
Spectral Class
G-type yellow (Sun-like)
Effective Temperature
5,751 K — cooler than the Sun (5,778 K)
Estimated Age
4.79 Gyr — older than the Sun (4.6 Gyr)
Stellar Radius
1.430 R☉
Stellar Mass
1.229 M☉
Metallicity [Fe/H]
0.34
Extended Stellar Properties
Surface gravity (log g)
4.194 dex
Stellar density
0.419 g/cm³
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 16 bands
Astrometric Data
Parallax
0.527 mas
Total Proper Motion
0.843 mas/yr
PM Right Ascension
-0.17 mas/yr
PM Declination
-0.83 mas/yr
Galactic Cartesian (pc)
x = 0.233 · y = -0.722 · z = 0.651
Equatorial (J2000)
RA 287.89711° · Dec 40.63781°
Galactic ℓ, b
71.835° · 13.749°
Ecliptic λ, β
300.023° · 62.224°
HTM-20 index
-1303763685
Similar Worlds
Kepler-1494 b
Sub-Neptune · G-type yellow (Sun-like)
Radius 3.07 R⊕ · 4,192.7 ly
Kepler-293 b
Sub-Neptune · G-type yellow (Sun-like)
Radius 3.07 R⊕ · 3,178.8 ly
Kepler-335 c
Sub-Neptune · G-type yellow (Sun-like)
Radius 3.07 R⊕ · 4,171.4 ly
Kepler-1929 b
Sub-Neptune · G-type yellow (Sun-like)
Radius 3.07 R⊕ · 1,657.5 ly
HD 63935 c
Sub-Neptune · G-type yellow (Sun-like)
Radius 3.06 R⊕ · 159.7 ly
Kepler-941 b
Sub-Neptune · G-type yellow (Sun-like)
Radius 3.08 R⊕ · 3,549.8 ly