Key parameters at a glance
- A radius of 1.42 Earth radii
- A mass of 3.79 Earth masses
- Surface gravity around 1.88 g
- An orbital period of 15.000 days
- Semi-major axis 0.1255 AU
- Equilibrium temperature 968 K (695 °C)
- Distance from Earth 1,292.81 light-years
- Earth Similarity Index 0.301
- Travel time at Voyager 1 speed 22,798,772 years
1 sibling around Kepler-128
Kepler-128 b 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-128 b this | Super-Earth | 1.42 | 3.79 | 15.000 | 968 | 2013 |
| Kepler-128 c | Super-Earth | 1.52 | 3.38 | 22.800 | 843 | 2013 |
Kepler-128 b Planet Profile
Physical Specs
Classification
Planet Type
Super-Earth
Discovery
Size rank in cohort
Rank by radius
#882of 1176
top 74.9%
This planet
1.42R⊕
Super-Earth median
1.60R⊕
Nearest-size peers
| Metric | Earth | Kepler-128 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 1.42 | 11.21 |
| Mass (M⊕) | 1.00 | 3.79 | 317.83 |
| Density (g/cm³) | 5.51 | 7.22 | 1.33 |
| Surface Gravity (g) | 1.00 | 1.88 | 2.53 |
| Insolation (S⊕) | 1.00 | 227.40 | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Best measured mass | 3.790 M⊕ | Direct mass measurement (not derived). |
Star Catalogue Identifiers
TIC
TIC 123490545
Gaia DR2
Gaia DR2 2105318412166111232
Gaia DR3
Gaia DR3 2105318412166111232
System
Kepler-128
Percentile among Super-Earth cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 15.00 Earth days (4.1% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.1255 AU.
Transit Fingerprint
Depth
0.007 %
Duration
4.211 h
Impact parameter b
0.440
Rp / R★
0.008074
Transit midpoint (BJD)
2,455,008.9556
Photometric dip
Transit produces a flux drop of 74 ppm lasting ≈ 4.21 h.
Extended Orbital Architecture
Planet / star radius ratio
0.008074
Semi-major axis / stellar radius
27.592
Impact parameter (b)
0.440
Transit mid-time (BJD)
2,455,008.9556
Angular separation (arcsec)
0.31600
Eq. Temperature
968K
(695 °C)
Insolation (S⊕)
227.40
Earth = 1.00
Earth Similarity (ESI)
0.301
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
Discovery cohort
Planets confirmed in 2013 at Kepler (12 shown).
Host System: Kepler-128
Spectral Class
F-type yellow-white
Effective Temperature
6,072 K — hotter than the Sun (5,778 K)
Estimated Age
4.07 Gyr — younger than the Sun (4.6 Gyr)
Stellar Radius
1.659 R☉
Stellar Mass
1.184 M☉
Metallicity [Fe/H]
-0.03
Extended Stellar Properties
Surface gravity (log g)
4.070 dex
Stellar density
0.365 g/cm³
Systemic radial velocity
-21.30 km/s
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 16 bands
Astrometric Data
Parallax
2.494 mas
Total Proper Motion
13.350 mas/yr
PM Right Ascension
5.94 mas/yr
PM Declination
11.96 mas/yr
Galactic Cartesian (pc)
x = 0.156 · y = -0.703 · z = 0.694
Equatorial (J2000)
RA 282.49226° · Dec 43.98024°
Galactic ℓ, b
73.494° · 18.708°
Ecliptic λ, β
292.903° · 66.429°
HTM-20 index
-730316953
Similar Worlds
Kepler-403 d
Super-Earth · F-type yellow-white
Radius 1.42 R⊕ · 2,740.6 ly
Kepler-65 b
Super-Earth · F-type yellow-white
Radius 1.42 R⊕ · 990.6 ly
Kepler-1274 b
Super-Earth · F-type yellow-white
Radius 1.42 R⊕ · 2,004.7 ly
Kepler-1921 c
Super-Earth · F-type yellow-white
Radius 1.41 R⊕ · 3,030.0 ly
Kepler-1383 b
Super-Earth · F-type yellow-white
Radius 1.41 R⊕ · 3,350.3 ly
Kepler-187 b
Super-Earth · F-type yellow-white
Radius 1.41 R⊕ · 3,728.0 ly