Key parameters at a glance
- A radius of 3.60 Earth radii
- A mass of 10.50 Earth masses
- Surface gravity around 0.81 g
- An orbital period of 5.487 days
- Semi-major axis 0.0575 AU
- Equilibrium temperature 836 K (563 °C)
- Distance from Earth 2,832.59 light-years
- Earth Similarity Index 0.254
- 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 b 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 this | Sub-Neptune | 3.60 | 10.50 | 5.487 | 836 | 2013 |
| Kepler-305 c | 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 b Planet Profile
Physical Specs
Classification
Planet Type
Sub-Neptune
Discovery
Size rank in cohort
Rank by radius
#139of 1978
top 7.0%
This planet
3.60R⊕
Sub-Neptune median
2.71R⊕
Nearest-size peers
| Metric | Earth | Kepler-305 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 3.60 | 11.21 |
| Mass (M⊕) | 1.00 | 10.50 | 317.83 |
| Density (g/cm³) | 5.51 | 1.24 | 1.33 |
| Surface Gravity (g) | 1.00 | 0.81 | 2.53 |
| Insolation (S⊕) | 1.00 | 112.91 | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Best measured mass | 10.500 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 5.49 Earth days (1.5% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0575 AU.
Transit Fingerprint
Depth
0.133 %
Duration
2.930 h
Impact parameter b
0.806
Rp / R★
0.037400
Transit midpoint (BJD)
2,455,189.0773
Photometric dip
Transit produces a flux drop of 1,329 ppm lasting ≈ 2.93 h.
Extended Orbital Architecture
Planet / star radius ratio
0.037400
Semi-major axis / stellar radius
9.400
Impact parameter (b)
0.806
Transit mid-time (BJD)
2,455,189.0773
Angular separation (arcsec)
0.06620
Eq. Temperature
836K
(563 °C)
Insolation (S⊕)
112.91
Earth = 1.00
Earth Similarity (ESI)
0.254
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
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