Key parameters at a glance
- A radius of 3.61 Earth radii
- A mass of 12.70 Earth masses
- Surface gravity around 0.97 g
- An orbital period of 33.653 days
- Semi-major axis 0.1930 AU
- Equilibrium temperature 470 K (197 °C)
- Distance from Earth 1,878.62 light-years
- Earth Similarity Index 0.451
- Travel time at Voyager 1 speed 33,129,452 years
- Almost certainly tidally locked to its host star given the close orbit
1 sibling around Kepler-258
Kepler-258 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-258 b | Neptune-like | 4.06 | 15.50 | 13.197 | 642 | 2014 |
| Kepler-258 c this | Sub-Neptune | 3.61 | 12.70 | 33.653 | 470 | 2014 |
Kepler-258 c Planet Profile
Physical Specs
Classification
Planet Type
Sub-Neptune
Discovery
Size rank in cohort
Rank by radius
#132of 1978
top 6.6%
This planet
3.61R⊕
Sub-Neptune median
2.71R⊕
Nearest-size peers
| Metric | Earth | Kepler-258 c | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 3.61 | 11.21 |
| Mass (M⊕) | 1.00 | 12.70 | 317.83 |
| Density (g/cm³) | 5.51 | 1.48 | 1.33 |
| Surface Gravity (g) | 1.00 | 0.97 | 2.53 |
| Insolation (S⊕) | 1.00 | 7.99 | 0.037 |
Star Catalogue Identifiers
TIC
TIC 270854411
Gaia DR2
Gaia DR2 2128150217796747520
Gaia DR3
Gaia DR3 2128150217796747520
System
Kepler-258
Percentile among Sub-Neptune cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 33.65 Earth days (9.2% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.1930 AU.
Transit Fingerprint
Depth
0.114 %
Duration
4.126 h
Impact parameter b
0.850
Rp / R★
0.038442
Transit midpoint (BJD)
2,454,980.7981
Photometric dip
Transit produces a flux drop of 1,141 ppm lasting ≈ 4.13 h.
Extended Orbital Architecture
Planet / star radius ratio
0.038442
Semi-major axis / stellar radius
55.900
Impact parameter (b)
0.850
Transit mid-time (BJD)
2,454,980.7981
Angular separation (arcsec)
0.33500
Eq. Temperature
470K
(197 °C)
Insolation (S⊕)
7.99
Earth = 1.00
Earth Similarity (ESI)
0.451
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.
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-258
Spectral Class
K-type orange
Effective Temperature
4,942 K — cooler than the Sun (5,778 K)
Estimated Age
13.70 Gyr — older than the Sun (4.6 Gyr)
Stellar Radius
0.915 R☉
Stellar Mass
0.820 M☉
Metallicity [Fe/H]
0.30
Extended Stellar Properties
Surface gravity (log g)
4.441 dex
Stellar density
3.030 g/cm³
Metallicity ratio
[M/H]
Multi-band Host Photometry — 16 bands
Astrometric Data
Parallax
1.708 mas
Total Proper Motion
31.941 mas/yr
PM Right Ascension
-11.47 mas/yr
PM Declination
-29.81 mas/yr
Galactic Cartesian (pc)
x = 0.280 · y = -0.628 · z = 0.726
Equatorial (J2000)
RA 294.06841° · Dec 46.57914°
Galactic ℓ, b
79.305° · 12.256°
Ecliptic λ, β
314.333° · 66.353°
HTM-20 index
-1309965895
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Kepler-1143 c
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