Key parameters at a glance
- A radius of 2.38 Earth radii
- A mass of 6.26 Earth masses
- Surface gravity around 1.11 g
- An orbital period of 34.260 days
- Semi-major axis 0.1950 AU
- Equilibrium temperature 468 K (195 °C)
- Distance from Earth 1,968.45 light-years
- Earth Similarity Index 0.536
- Travel time at Voyager 1 speed 34,713,602 years
2 siblings around Kepler-166
Kepler-166 c 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-166 d | Super-Earth | 1.73 | 3.64 | 1.554 | 1,313 | 2016 |
| Kepler-166 b | Sub-Neptune | 2.27 | 5.77 | 7.650 | 772 | 2014 |
| Kepler-166 c this | Sub-Neptune | 2.38 | 6.26 | 34.260 | 468 | 2014 |
Kepler-166 c Planet Profile
Physical Specs
Classification
Planet Type
Sub-Neptune
Discovery
Size rank in cohort
Rank by radius
#1365of 1978
top 69.0%
This planet
2.38R⊕
Sub-Neptune median
2.71R⊕
Nearest-size peers
| Metric | Earth | Kepler-166 c | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 2.38 | 11.21 |
| Mass (M⊕) | 1.00 | 6.26 | 317.83 |
| Density (g/cm³) | 5.51 | 2.55 | 1.33 |
| Surface Gravity (g) | 1.00 | 1.11 | 2.53 |
| Insolation (S⊕) | 1.00 | 10.51 | 0.037 |
Star Catalogue Identifiers
TIC
TIC 26814955
Gaia DR2
Gaia DR2 2129025841368107136
Gaia DR3
Gaia DR3 2129025841368107136
System
Kepler-166
Percentile among Sub-Neptune cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 34.26 Earth days (9.4% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.1950 AU.
Transit Fingerprint
Depth
0.107 %
Duration
4.840 h
Impact parameter b
0.230
Rp / R★
0.030068
Transit midpoint (BJD)
2,455,016.2265
Photometric dip
Transit produces a flux drop of 1,073 ppm lasting ≈ 4.84 h.
Extended Orbital Architecture
Planet / star radius ratio
0.030068
Semi-major axis / stellar radius
56.439
Impact parameter (b)
0.230
Transit mid-time (BJD)
2,455,016.2265
Angular separation (arcsec)
0.32300
Eq. Temperature
468K
(195 °C)
Insolation (S⊕)
10.51
Earth = 1.00
Earth Similarity (ESI)
0.536
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-166
Spectral Class
G-type yellow (Sun-like)
Effective Temperature
5,413 K — cooler than the Sun (5,778 K)
Estimated Age
5.01 Gyr — older than the Sun (4.6 Gyr)
Stellar Radius
0.742 R☉
Stellar Mass
0.811 M☉
Metallicity [Fe/H]
-0.08
Extended Stellar Properties
Surface gravity (log g)
4.619 dex
Stellar density
1.750 g/cm³
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 16 bands
Astrometric Data
Parallax
1.628 mas
Total Proper Motion
7.177 mas/yr
PM Right Ascension
-6.63 mas/yr
PM Declination
-2.75 mas/yr
Galactic Cartesian (pc)
x = 0.259 · y = -0.605 · z = 0.753
Equatorial (J2000)
RA 293.16010° · Dec 48.88121°
Galactic ℓ, b
81.149° · 13.819°
Ecliptic λ, β
315.395° · 68.700°
HTM-20 index
-778595354
Similar Worlds
Kepler-189 c
Sub-Neptune · G-type yellow (Sun-like)
Radius 2.38 R⊕ · 1,929.3 ly
Kepler-1060 b
Sub-Neptune · G-type yellow (Sun-like)
Radius 2.38 R⊕ · 3,087.3 ly
Kepler-1071 b
Sub-Neptune · G-type yellow (Sun-like)
Radius 2.38 R⊕ · 3,399.4 ly
Kepler-639 b
Sub-Neptune · G-type yellow (Sun-like)
Radius 2.38 R⊕ · 2,773.1 ly
Kepler-1781 b
Sub-Neptune · G-type yellow (Sun-like)
Radius 2.38 R⊕ · 3,139.7 ly
Kepler-1872 b
Sub-Neptune · G-type yellow (Sun-like)
Radius 2.38 R⊕ · 2,740.3 ly