Key parameters at a glance
- A radius of 1.73 Earth radii
- A mass of 3.64 Earth masses
- Surface gravity around 1.22 g
- An orbital period of 1.554 days
- Semi-major axis 0.0245 AU
- Equilibrium temperature 1,313 K (1040 °C)
- Distance from Earth 1,968.45 light-years
- Earth Similarity Index 0.211
- Travel time at Voyager 1 speed 34,713,602 years
2 siblings around Kepler-166
Kepler-166 d 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 this | 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 | Sub-Neptune | 2.38 | 6.26 | 34.260 | 468 | 2014 |
Kepler-166 d Planet Profile
Physical Specs
Classification
Planet Type
Super-Earth
Discovery
Size rank in cohort
Rank by radius
#356of 1176
top 30.2%
This planet
1.73R⊕
Super-Earth median
1.60R⊕
Nearest-size peers
| Metric | Earth | Kepler-166 d | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 1.73 | 11.21 |
| Mass (M⊕) | 1.00 | 3.64 | 317.83 |
| Density (g/cm³) | 5.51 | 3.86 | 1.33 |
| Surface Gravity (g) | 1.00 | 1.22 | 2.53 |
| Insolation (S⊕) | 1.00 | 651.41 | 0.037 |
Star Catalogue Identifiers
TIC
TIC 26814955
Gaia DR2
Gaia DR2 2129025841368107136
Gaia DR3
Gaia DR3 2129025841368107136
System
Kepler-166
Percentile among Super-Earth cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 1.55 Earth days (0.4% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0245 AU.
Transit Fingerprint
Depth
0.047 %
Duration
1.770 h
Impact parameter b
0.720
Rp / R★
0.019023
Transit midpoint (BJD)
2,455,002.8305
Photometric dip
Transit produces a flux drop of 466 ppm lasting ≈ 1.77 h.
Extended Orbital Architecture
Planet / star radius ratio
0.019023
Semi-major axis / stellar radius
6.791
Impact parameter (b)
0.720
Transit mid-time (BJD)
2,455,002.8305
Angular separation (arcsec)
0.04060
Eq. Temperature
1,313K
(1040 °C)
Insolation (S⊕)
651.41
Earth = 1.00
Earth Similarity (ESI)
0.211
0 = alien, 1 = Earth-identical
Inside the inner HZ boundary (too hot for liquid water) — the dayside is scorched.
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-166
Spectral Class
G-type yellow (Sun-like)
Effective Temperature
5,350 K — cooler than the Sun (5,778 K)
Estimated Age
4.47 Gyr — younger than the Sun (4.6 Gyr)
Stellar Radius
0.830 R☉
Stellar Mass
0.880 M☉
Metallicity [Fe/H]
-0.03
Extended Stellar Properties
Surface gravity (log g)
4.550 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-1126 b
Super-Earth · G-type yellow (Sun-like)
Radius 1.73 R⊕ · 2,073.5 ly
Kepler-1522 b
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Radius 1.73 R⊕ · 2,655.3 ly
Kepler-1468 b
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Kepler-1153 b
Super-Earth · G-type yellow (Sun-like)
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Kepler-1478 b
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Kepler-238 b
Super-Earth · G-type yellow (Sun-like)
Radius 1.73 R⊕ · 5,866.7 ly