Key parameters at a glance
- A radius of 2.82 Earth radii
- A mass of 8.35 Earth masses
- Surface gravity around 1.05 g
- An orbital period of 17.790 days
- Semi-major axis 0.1310 AU
- Equilibrium temperature 655 K (382 °C)
- Distance from Earth 1,615.64 light-years
- Earth Similarity Index 0.369
- Travel time at Voyager 1 speed 28,491,807 years
2 siblings around Kepler-198
Kepler-198 b 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-198 d | Super-Earth | 1.53 | 2.96 | 1.312 | 1,562 | 2016 |
| Kepler-198 b this | Sub-Neptune | 2.82 | 8.35 | 17.790 | 655 | 2014 |
| Kepler-198 c | Sub-Neptune | 2.47 | 6.66 | 49.567 | 465 | 2014 |
Kepler-198 b Planet Profile
Physical Specs
Classification
Planet Type
Sub-Neptune
Discovery
Size rank in cohort
Rank by radius
#720of 1978
top 36.3%
This planet
2.82R⊕
Sub-Neptune median
2.71R⊕
Nearest-size peers
| Metric | Earth | Kepler-198 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 2.82 | 11.21 |
| Mass (M⊕) | 1.00 | 8.35 | 317.83 |
| Density (g/cm³) | 5.51 | 2.05 | 1.33 |
| Surface Gravity (g) | 1.00 | 1.05 | 2.53 |
| Insolation (S⊕) | 1.00 | 44.55 | 0.037 |
Star Catalogue Identifiers
TIC
TIC 122519154
Gaia DR2
Gaia DR2 2052852912747829760
Gaia DR3
Gaia DR3 2052852912747829760
System
Kepler-198
Percentile among Sub-Neptune cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 17.79 Earth days (4.9% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.1310 AU.
Transit Fingerprint
Depth
0.095 %
Duration
4.478 h
Impact parameter b
0.030
Rp / R★
0.028028
Transit midpoint (BJD)
2,455,015.4364
Photometric dip
Transit produces a flux drop of 952 ppm lasting ≈ 4.48 h.
Extended Orbital Architecture
Planet / star radius ratio
0.028028
Semi-major axis / stellar radius
31.384
Impact parameter (b)
0.030
Transit mid-time (BJD)
2,455,015.4364
Angular separation (arcsec)
0.26400
Eq. Temperature
655K
(382 °C)
Insolation (S⊕)
44.55
Earth = 1.00
Earth Similarity (ESI)
0.369
0 = alien, 1 = Earth-identical
Inside the inner HZ boundary (too hot for liquid water) — the surface is too hot to retain surface water.
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-198
Spectral Class
G-type yellow (Sun-like)
Effective Temperature
5,574 K — cooler than the Sun (5,778 K)
Estimated Age
0.51 Gyr — younger than the Sun (4.6 Gyr)
Stellar Radius
0.940 R☉
Stellar Mass
0.995 M☉
Metallicity [Fe/H]
0.11
Extended Stellar Properties
Surface gravity (log g)
4.467 dex
Stellar density
1.370 g/cm³
Metallicity ratio
[M/H]
Multi-band Host Photometry — 17 bands
Astrometric Data
Parallax
1.990 mas
Total Proper Motion
2.583 mas/yr
PM Right Ascension
-1.68 mas/yr
PM Declination
1.96 mas/yr
Galactic Cartesian (pc)
x = 0.276 · y = -0.730 · z = 0.625
Equatorial (J2000)
RA 290.67313° · Dec 38.69100°
Galactic ℓ, b
70.959° · 10.988°
Ecliptic λ, β
303.180° · 59.771°
HTM-20 index
1935567964
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