Key parameters at a glance
- A radius of 2.27 Earth radii
- A mass of 5.77 Earth masses
- Surface gravity around 1.12 g
- An orbital period of 7.650 days
- Semi-major axis 0.0720 AU
- Equilibrium temperature 772 K (499 °C)
- Distance from Earth 1,968.45 light-years
- Earth Similarity Index 0.340
- Travel time at Voyager 1 speed 34,713,602 years
2 siblings around Kepler-166
Kepler-166 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-166 d | Super-Earth | 1.73 | 3.64 | 1.554 | 1,313 | 2016 |
| Kepler-166 b this | Sub-Neptune | 2.27 | 5.77 | 7.650 | 772 | 2014 |
| Kepler-166 c | Sub-Neptune | 2.38 | 6.26 | 34.260 | 468 | 2014 |
Kepler-166 b Planet Profile
Physical Specs
Classification
Planet Type
Sub-Neptune
Discovery
Size rank in cohort
Rank by radius
#1554of 1978
top 78.5%
This planet
2.27R⊕
Sub-Neptune median
2.71R⊕
Nearest-size peers
| Metric | Earth | Kepler-166 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 2.27 | 11.21 |
| Mass (M⊕) | 1.00 | 5.77 | 317.83 |
| Density (g/cm³) | 5.51 | 2.71 | 1.33 |
| Surface Gravity (g) | 1.00 | 1.12 | 2.53 |
| Insolation (S⊕) | 1.00 | 77.54 | 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 7.65 Earth days (2.1% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0720 AU.
Transit Fingerprint
Depth
0.098 %
Duration
2.749 h
Impact parameter b
0.090
Rp / R★
0.028274
Transit midpoint (BJD)
2,455,004.9715
Photometric dip
Transit produces a flux drop of 981 ppm lasting ≈ 2.75 h.
Extended Orbital Architecture
Planet / star radius ratio
0.028274
Semi-major axis / stellar radius
21.895
Impact parameter (b)
0.090
Transit mid-time (BJD)
2,455,004.9715
Angular separation (arcsec)
0.11900
Eq. Temperature
772K
(499 °C)
Insolation (S⊕)
77.54
Earth = 1.00
Earth Similarity (ESI)
0.340
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-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-1985 b
Sub-Neptune · G-type yellow (Sun-like)
Radius 2.27 R⊕ · —
Kepler-759 b
Sub-Neptune · G-type yellow (Sun-like)
Radius 2.27 R⊕ · 3,501.2 ly
Kepler-589 b
Sub-Neptune · G-type yellow (Sun-like)
Radius 2.27 R⊕ · 1,998.7 ly
Kepler-121 c
Sub-Neptune · G-type yellow (Sun-like)
Radius 2.27 R⊕ · 1,665.1 ly
Kepler-183 c
Sub-Neptune · G-type yellow (Sun-like)
Radius 2.27 R⊕ · 3,426.7 ly
Kepler-226 c
Sub-Neptune · G-type yellow (Sun-like)
Radius 2.27 R⊕ · 3,196.8 ly