Key parameters at a glance
- A radius of 2.99 Earth radii
- A mass of 9.22 Earth masses
- Surface gravity around 1.03 g
- An orbital period of 49.622 days
- Semi-major axis 0.2726 AU
- Equilibrium temperature 546 K (273 °C)
- Distance from Earth 2,226.09 light-years
- Earth Similarity Index 0.428
- Travel time at Voyager 1 speed 39,257,032 years
Kepler-978 b Planet Profile
Physical Specs
Classification
Planet Type
Sub-Neptune
Discovery
Size rank in cohort
Rank by radius
#529of 1978
top 26.7%
This planet
2.99R⊕
Sub-Neptune median
2.71R⊕
Nearest-size peers
| Metric | Earth | Kepler-978 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 2.99 | 11.21 |
| Mass (M⊕) | 1.00 | 9.22 | 317.83 |
| Density (g/cm³) | 5.51 | 1.90 | 1.33 |
| Surface Gravity (g) | 1.00 | 1.03 | 2.53 |
| Insolation (S⊕) | 1.00 | 20.99 | 0.037 |
Star Catalogue Identifiers
TIC
TIC 158317637
Gaia DR2
Gaia DR2 2105597825559486336
Gaia DR3
Gaia DR3 2105597825559486336
System
Kepler-978
Percentile among Sub-Neptune cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 49.62 Earth days (13.6% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.2726 AU.
Transit Fingerprint
Depth
0.049 %
Duration
7.093 h
Impact parameter b
0.670
Rp / R★
0.024681
Transit midpoint (BJD)
2,454,970.1003
Photometric dip
Transit produces a flux drop of 491 ppm lasting ≈ 7.09 h.
Extended Orbital Architecture
Planet / star radius ratio
0.024681
Semi-major axis / stellar radius
21.700
Impact parameter (b)
0.670
Transit mid-time (BJD)
2,454,970.1003
Angular separation (arcsec)
0.39900
Eq. Temperature
546K
(273 °C)
Insolation (S⊕)
20.99
Earth = 1.00
Earth Similarity (ESI)
0.428
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
Morton et al. 2016Instrument
Kepler CCD Array
Publication
2016-05
Observation locale
Space
Discovery cohort
Planets confirmed in 2016 at Kepler (12 shown).
Host System: Kepler-978
Spectral Class
F-type yellow-white
Effective Temperature
6,002 K — hotter than the Sun (5,778 K)
Estimated Age
3.63 Gyr — younger than the Sun (4.6 Gyr)
Stellar Radius
1.090 R☉
Stellar Mass
1.070 M☉
Metallicity [Fe/H]
-0.01
Extended Stellar Properties
Surface gravity (log g)
4.380 dex
Stellar density
0.096 g/cm³
Systemic radial velocity
22.78 km/s
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 16 bands
Astrometric Data
Parallax
0.961 mas
Total Proper Motion
14.702 mas/yr
PM Right Ascension
7.46 mas/yr
PM Declination
-12.67 mas/yr
Galactic Cartesian (pc)
x = 0.210 · y = -0.700 · z = 0.683
Equatorial (J2000)
RA 286.71072° · Dec 43.04336°
Galactic ℓ, b
73.751° · 15.518°
Ecliptic λ, β
299.544° · 64.778°
HTM-20 index
1118043275
Similar Worlds
Kepler-1717 b
Sub-Neptune · F-type yellow-white
Radius 2.99 R⊕ · 3,290.2 ly
Kepler-457 d
Sub-Neptune · F-type yellow-white
Radius 2.98 R⊕ · 3,497.4 ly
K2-278 b
Sub-Neptune · F-type yellow-white
Radius 2.98 R⊕ · 2,565.0 ly
K2-258 b
Sub-Neptune · F-type yellow-white
Radius 3.00 R⊕ · 2,158.7 ly
Kepler-956 b
Sub-Neptune · F-type yellow-white
Radius 3.00 R⊕ · 1,777.4 ly
Kepler-1672 b
Sub-Neptune · F-type yellow-white
Radius 2.97 R⊕ · 1,275.9 ly