Key parameters at a glance
- A radius of 3.30 Earth radii
- A mass of 6.00 Earth masses
- Surface gravity around 0.55 g
- An orbital period of 8.291 days
- Semi-major axis 0.0757 AU
- Equilibrium temperature 728 K (455 °C)
- Distance from Earth 2,832.59 light-years
- Earth Similarity Index 0.282
- Travel time at Voyager 1 speed 49,952,719 years
- Almost certainly tidally locked to its host star given the close orbit
3 siblings around Kepler-305
Kepler-305 c 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-305 e | Super-Earth | 1.79 | 3.87 | 3.205 | 1,000 | 2020 |
| Kepler-305 b | Sub-Neptune | 3.60 | 10.50 | 5.487 | 836 | 2013 |
| Kepler-305 c this | Sub-Neptune | 3.30 | 6.00 | 8.291 | 728 | 2013 |
| Kepler-305 d | Sub-Neptune | 2.76 | 6.20 | 16.740 | 576 | 2014 |
Kepler-305 c Planet Profile
Physical Specs
Classification
Planet Type
Sub-Neptune
Discovery
Size rank in cohort
Rank by radius
#280of 1978
top 14.1%
This planet
3.30R⊕
Sub-Neptune median
2.71R⊕
Nearest-size peers
| Metric | Earth | Kepler-305 c | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 3.30 | 11.21 |
| Mass (M⊕) | 1.00 | 6.00 | 317.83 |
| Density (g/cm³) | 5.51 | 0.92 | 1.33 |
| Surface Gravity (g) | 1.00 | 0.55 | 2.53 |
| Insolation (S⊕) | 1.00 | 65.10 | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Best measured mass | 6.000 M⊕ | Direct mass measurement (not derived). |
Star Catalogue Identifiers
TIC
TIC 171879024
Gaia DR2
Gaia DR2 2073547954981763328
Gaia DR3
Gaia DR3 2073547954981763328
System
Kepler-305
Percentile among Sub-Neptune cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 8.29 Earth days (2.3% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0757 AU.
Transit Fingerprint
Depth
0.103 %
Duration
3.613 h
Impact parameter b
0.839
Rp / R★
0.033000
Transit midpoint (BJD)
2,455,192.6349
Photometric dip
Transit produces a flux drop of 1,034 ppm lasting ≈ 3.61 h.
Extended Orbital Architecture
Planet / star radius ratio
0.033000
Semi-major axis / stellar radius
12.400
Impact parameter (b)
0.839
Transit mid-time (BJD)
2,455,192.6349
Angular separation (arcsec)
0.08710
Eq. Temperature
728K
(455 °C)
Insolation (S⊕)
65.10
Earth = 1.00
Earth Similarity (ESI)
0.282
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
Discovery cohort
Planets confirmed in 2013 at Kepler (12 shown).
Host System: Kepler-305
Spectral Class
K-type orange
Effective Temperature
5,080 K — cooler than the Sun (5,778 K)
Estimated Age
4.37 Gyr — younger than the Sun (4.6 Gyr)
Stellar Radius
0.800 R☉
Stellar Mass
0.760 M☉
Metallicity [Fe/H]
0.09
Extended Stellar Properties
Surface gravity (log g)
4.510 dex
Stellar density
1.740 g/cm³
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 16 bands
Astrometric Data
Parallax
1.124 mas
Total Proper Motion
11.427 mas/yr
PM Right Ascension
-11.12 mas/yr
PM Declination
-2.61 mas/yr
Galactic Cartesian (pc)
x = 0.372 · y = -0.665 · z = 0.647
Equatorial (J2000)
RA 299.22426° · Dec 40.34317°
Galactic ℓ, b
75.600° · 5.973°
Ecliptic λ, β
316.525° · 59.152°
HTM-20 index
-691944491
Similar Worlds
K2-266 b
Sub-Neptune · K-type orange
Radius 3.30 R⊕ · 253.0 ly
Kepler-1663 b
Sub-Neptune · K-type orange
Radius 3.30 R⊕ · 1,102.2 ly
TOI-431 d
Sub-Neptune · K-type orange
Radius 3.29 R⊕ · 106.2 ly
Kepler-1999 b
Sub-Neptune · K-type orange
Radius 3.29 R⊕ · 2,287.2 ly
Kepler-411 d
Sub-Neptune · K-type orange
Radius 3.32 R⊕ · 501.2 ly
Kepler-411 e
Sub-Neptune · K-type orange
Radius 3.28 R⊕ · 501.2 ly