Key parameters at a glance
- A radius of 2.16 Earth radii
- A mass of 5.31 Earth masses
- Surface gravity around 1.14 g
- An orbital period of 15.382 days
- Semi-major axis 0.1230 AU
- Equilibrium temperature 714 K (441 °C)
- Distance from Earth 4,357.18 light-years
- Earth Similarity Index 0.375
- Travel time at Voyager 1 speed 76,838,922 years
1 sibling around Kepler-308
Kepler-308 c shares its host star with 1 other confirmed planet. Side-by-side measurements below.
| Planet | Type | Radius (R⊕) | Mass (M⊕) | Period (d) | Eq. T (K) | Year |
|---|---|---|---|---|---|---|
| Kepler-308 b | Sub-Neptune | 2.12 | 5.14 | 9.695 | 833 | 2014 |
| Kepler-308 c this | Sub-Neptune | 2.16 | 5.31 | 15.382 | 714 | 2014 |
Kepler-308 c Planet Profile
Physical Specs
Classification
Planet Type
Sub-Neptune
Discovery
Size rank in cohort
Rank by radius
#1731of 1978
top 87.5%
This planet
2.16R⊕
Sub-Neptune median
2.71R⊕
Nearest-size peers
| Metric | Earth | Kepler-308 c | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 2.16 | 11.21 |
| Mass (M⊕) | 1.00 | 5.31 | 317.83 |
| Density (g/cm³) | 5.51 | 2.90 | 1.33 |
| Surface Gravity (g) | 1.00 | 1.14 | 2.53 |
| Insolation (S⊕) | 1.00 | 58.68 | 0.037 |
Star Catalogue Identifiers
TIC
TIC 184162776
Gaia DR2
Gaia DR2 2076400156855612416
Gaia DR3
Gaia DR3 2076400156855612416
System
Kepler-308
Percentile among Sub-Neptune cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 15.38 Earth days (4.2% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.1230 AU.
Transit Fingerprint
Depth
0.055 %
Duration
3.951 h
Impact parameter b
0.190
Rp / R★
0.021393
Transit midpoint (BJD)
2,454,972.0828
Photometric dip
Transit produces a flux drop of 551 ppm lasting ≈ 3.95 h.
Extended Orbital Architecture
Planet / star radius ratio
0.021393
Semi-major axis / stellar radius
31.470
Impact parameter (b)
0.190
Transit mid-time (BJD)
2,454,972.0828
Angular separation (arcsec)
0.09210
Eq. Temperature
714K
(441 °C)
Insolation (S⊕)
58.68
Earth = 1.00
Earth Similarity (ESI)
0.375
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-308
Spectral Class
G-type yellow (Sun-like)
Effective Temperature
5,895 K — hotter than the Sun (5,778 K)
Estimated Age
0.50 Gyr — younger than the Sun (4.6 Gyr)
Stellar Radius
0.941 R☉
Stellar Mass
0.920 M☉
Metallicity [Fe/H]
-0.04
Extended Stellar Properties
Surface gravity (log g)
4.508 dex
Stellar density
2.260 g/cm³
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 16 bands
Astrometric Data
Parallax
0.722 mas
Total Proper Motion
14.568 mas/yr
PM Right Ascension
12.82 mas/yr
PM Declination
6.92 mas/yr
Galactic Cartesian (pc)
x = 0.331 · y = -0.685 · z = 0.649
Equatorial (J2000)
RA 295.78524° · Dec 40.43958°
Galactic ℓ, b
74.372° · 8.294°
Ecliptic λ, β
311.761° · 60.195°
HTM-20 index
-1519638453
Similar Worlds
HD 86226 c
Sub-Neptune · G-type yellow (Sun-like)
Radius 2.16 R⊕ · 149.0 ly
Kepler-1474 b
Sub-Neptune · G-type yellow (Sun-like)
Radius 2.16 R⊕ · 3,851.6 ly
Kepler-745 b
Sub-Neptune · G-type yellow (Sun-like)
Radius 2.16 R⊕ · 5,806.8 ly
Kepler-142 d
Sub-Neptune · G-type yellow (Sun-like)
Radius 2.16 R⊕ · 1,789.6 ly
Kepler-1322 c
Sub-Neptune · G-type yellow (Sun-like)
Radius 2.15 R⊕ · 4,404.1 ly
Kepler-797 b
Sub-Neptune · G-type yellow (Sun-like)
Radius 2.17 R⊕ · 4,289.8 ly