Key parameters at a glance
- A radius of 3.00 Earth radii
- A mass of 9.27 Earth masses
- Surface gravity around 1.03 g
- An orbital period of 44.431 days
- Semi-major axis 0.2570 AU
- Equilibrium temperature 680 K (407 °C)
- Distance from Earth 1,802.98 light-years
- Earth Similarity Index 0.347
- Travel time at Voyager 1 speed 31,795,618 years
3 siblings around Kepler-338
Kepler-338 d shares its host star with 3 other confirmed planets. Side-by-side measurements below.
| Planet | Type | Radius (R⊕) | Mass (M⊕) | Period (d) | Eq. T (K) | Year |
|---|---|---|---|---|---|---|
| Kepler-338 e | Super-Earth | 1.56 | 8.50 | 9.341 | 1,143 | 2014 |
| Kepler-338 b | Sub-Neptune | 2.44 | 30.60 | 13.727 | 1,005 | 2014 |
| Kepler-338 c | Sub-Neptune | 2.34 | 6.08 | 24.311 | 831 | 2014 |
| Kepler-338 d this | Sub-Neptune | 3.00 | 9.27 | 44.431 | 680 | 2014 |
Kepler-338 d Planet Profile
Physical Specs
Classification
Planet Type
Sub-Neptune
Discovery
Size rank in cohort
Rank by radius
#521of 1978
top 26.3%
This planet
3.00R⊕
Sub-Neptune median
2.71R⊕
Nearest-size peers
| Metric | Earth | Kepler-338 d | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 3.00 | 11.21 |
| Mass (M⊕) | 1.00 | 9.27 | 317.83 |
| Density (g/cm³) | 5.51 | 1.89 | 1.33 |
| Surface Gravity (g) | 1.00 | 1.03 | 2.53 |
| Insolation (S⊕) | 1.00 | 53.56 | 0.037 |
Star Catalogue Identifiers
TIC
TIC 258203303
Gaia DR2
Gaia DR2 2104344141784539264
Gaia DR3
Gaia DR3 2104344141784539264
System
Kepler-338
Percentile among Sub-Neptune cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 44.43 Earth days (12.2% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.2570 AU.
Transit Fingerprint
Depth
0.024 %
Duration
10.624 h
Impact parameter b
0.790
Rp / R★
0.014920
Transit midpoint (BJD)
2,454,976.5420
Photometric dip
Transit produces a flux drop of 239 ppm lasting ≈ 10.62 h.
Extended Orbital Architecture
Planet / star radius ratio
0.014920
Semi-major axis / stellar radius
25.100
Impact parameter (b)
0.790
Transit mid-time (BJD)
2,454,976.5420
Angular separation (arcsec)
0.46500
Eq. Temperature
680K
(407 °C)
Insolation (S⊕)
53.56
Earth = 1.00
Earth Similarity (ESI)
0.347
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-338
Spectral Class
G-type yellow (Sun-like)
Effective Temperature
5,923 K — hotter than the Sun (5,778 K)
Estimated Age
6.46 Gyr — older than the Sun (4.6 Gyr)
Stellar Radius
1.735 R☉
Stellar Mass
1.105 M☉
Metallicity [Fe/H]
-0.03
Extended Stellar Properties
Surface gravity (log g)
4.017 dex
Stellar density
0.210 g/cm³
Systemic radial velocity
-15.36 km/s
Metallicity ratio
[M/H]
Multi-band Host Photometry — 17 bands
Astrometric Data
Parallax
1.780 mas
Total Proper Motion
22.197 mas/yr
PM Right Ascension
16.22 mas/yr
PM Declination
15.15 mas/yr
Galactic Cartesian (pc)
x = 0.170 · y = -0.738 · z = 0.653
Equatorial (J2000)
RA 282.97906° · Dec 40.78442°
Galactic ℓ, b
70.483° · 17.244°
Ecliptic λ, β
292.177° · 63.228°
HTM-20 index
-861789349
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