Key parameters at a glance
- A radius of 3.95 Earth radii
- A mass of 14.80 Earth masses
- Surface gravity around 0.95 g
- An orbital period of 96.679 days
- Semi-major axis 0.3970 AU
- Equilibrium temperature 392 K (119 °C)
- Distance from Earth 2,335.36 light-years
- Earth Similarity Index 0.506
- Travel time at Voyager 1 speed 41,184,045 years
2 siblings around Kepler-178
Kepler-178 d shares its host star with 2 other confirmed planets. Side-by-side measurements below.
| Planet | Type | Radius (R⊕) | Mass (M⊕) | Period (d) | Eq. T (K) | Year |
|---|---|---|---|---|---|---|
| Kepler-178 b | Sub-Neptune | 2.90 | 8.75 | 9.577 | 846 | 2014 |
| Kepler-178 c | Sub-Neptune | 2.88 | 8.65 | 20.553 | 656 | 2014 |
| Kepler-178 d this | Sub-Neptune | 3.95 | 14.80 | 96.679 | 392 | 2014 |
Kepler-178 d Planet Profile
Physical Specs
Classification
Planet Type
Sub-Neptune
Discovery
Size rank in cohort
Rank by radius
#9of 1978
top 0.4%
This planet
3.95R⊕
Sub-Neptune median
2.71R⊕
Nearest-size peers
| Metric | Earth | Kepler-178 d | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 3.95 | 11.21 |
| Mass (M⊕) | 1.00 | 14.80 | 317.83 |
| Density (g/cm³) | 5.51 | 1.32 | 1.33 |
| Surface Gravity (g) | 1.00 | 0.95 | 2.53 |
| Insolation (S⊕) | 1.00 | 3.87 | 0.037 |
Star Catalogue Identifiers
TIC
TIC 158394235
Gaia DR2
Gaia DR2 2130634667395736704
Gaia DR3
Gaia DR3 2130634667395736704
System
Kepler-178
Percentile among Sub-Neptune cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 96.68 Earth days (26.5% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.3970 AU.
Transit Fingerprint
Depth
0.095 %
Duration
6.276 h
Impact parameter b
0.870
Rp / R★
0.028035
Transit midpoint (BJD)
2,454,973.1784
Photometric dip
Transit produces a flux drop of 951 ppm lasting ≈ 6.28 h.
Extended Orbital Architecture
Planet / star radius ratio
0.028035
Semi-major axis / stellar radius
126.000
Impact parameter (b)
0.870
Transit mid-time (BJD)
2,454,973.1784
Angular separation (arcsec)
0.55400
Eq. Temperature
392K
(119 °C)
Insolation (S⊕)
3.87
Earth = 1.00
Earth Similarity (ESI)
0.506
0 = alien, 1 = Earth-identical
Inside the inner HZ boundary (too hot for liquid water) — the surface is too hot to retain surface water.
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
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-178
Spectral Class
G-type yellow (Sun-like)
Effective Temperature
5,676 K — cooler than the Sun (5,778 K)
Estimated Age
9.12 Gyr — older than the Sun (4.6 Gyr)
Stellar Radius
1.066 R☉
Stellar Mass
0.852 M☉
Metallicity [Fe/H]
-0.04
Extended Stellar Properties
Surface gravity (log g)
4.334 dex
Stellar density
1.250 g/cm³
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 16 bands
Astrometric Data
Parallax
1.368 mas
Total Proper Motion
20.958 mas/yr
PM Right Ascension
-6.63 mas/yr
PM Declination
-19.88 mas/yr
Galactic Cartesian (pc)
x = 0.201 · y = -0.653 · z = 0.730
Equatorial (J2000)
RA 287.10103° · Dec 46.89640°
Galactic ℓ, b
77.568° · 16.735°
Ecliptic λ, β
303.049° · 68.382°
HTM-20 index
-1665530804
Similar Worlds
K2-193 b
Sub-Neptune · G-type yellow (Sun-like)
Radius 3.95 R⊕ · 1,343.5 ly
Kepler-552 b
Sub-Neptune · G-type yellow (Sun-like)
Radius 3.95 R⊕ · 2,751.7 ly
Kepler-1719 b
Sub-Neptune · G-type yellow (Sun-like)
Radius 3.95 R⊕ · 2,953.0 ly
Kepler-149 d
Sub-Neptune · G-type yellow (Sun-like)
Radius 3.96 R⊕ · 1,862.5 ly
Kepler-976 b
Sub-Neptune · G-type yellow (Sun-like)
Radius 3.96 R⊕ · 3,302.0 ly
Kepler-1405 b
Sub-Neptune · G-type yellow (Sun-like)
Radius 3.96 R⊕ · 4,991.2 ly