Key parameters at a glance
- A radius of 2.88 Earth radii
- A mass of 8.66 Earth masses
- Surface gravity around 1.04 g
- An orbital period of 25.848 days
- Semi-major axis 0.1761 AU
- Equilibrium temperature 672 K (399 °C)
- Distance from Earth 4,498.90 light-years
- Earth Similarity Index 0.357
- Travel time at Voyager 1 speed 79,338,062 years
1 sibling around Kepler-1666
Kepler-1666 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-1666 b this | Sub-Neptune | 2.88 | 8.66 | 25.848 | 672 | 2020 |
| Kepler-1666 c | Sub-Neptune | 3.24 | 10.50 | 40.716 | 578 | 2020 |
Kepler-1666 b Planet Profile
Physical Specs
Classification
Planet Type
Sub-Neptune
Discovery
Size rank in cohort
Rank by radius
#651of 1978
top 32.9%
This planet
2.88R⊕
Sub-Neptune median
2.71R⊕
Nearest-size peers
| Metric | Earth | Kepler-1666 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 2.88 | 11.21 |
| Mass (M⊕) | 1.00 | 8.66 | 317.83 |
| Density (g/cm³) | 5.51 | 1.99 | 1.33 |
| Surface Gravity (g) | 1.00 | 1.04 | 2.53 |
| Insolation (S⊕) | 1.00 | 48.23 | 0.037 |
Star Catalogue Identifiers
TIC
TIC 273685548
Gaia DR2
Gaia DR2 2079523903745213056
Gaia DR3
Gaia DR3 2079523903745213056
System
Kepler-1666
Percentile among Sub-Neptune cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 25.85 Earth days (7.1% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.1761 AU.
Transit Fingerprint
Depth
0.054 %
Duration
5.985 h
Impact parameter b
0.560
Rp / R★
0.021322
Transit midpoint (BJD)
2,455,021.8740
Photometric dip
Transit produces a flux drop of 537 ppm lasting ≈ 5.99 h.
Extended Orbital Architecture
Planet / star radius ratio
0.021322
Semi-major axis / stellar radius
33.650
Impact parameter (b)
0.560
Transit mid-time (BJD)
2,455,021.8740
Angular separation (arcsec)
0.12800
Eq. Temperature
672K
(399 °C)
Insolation (S⊕)
48.23
Earth = 1.00
Earth Similarity (ESI)
0.357
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
Armstrong et al. 2021Instrument
Kepler CCD Array
Publication
2021-07
Observation locale
Space
Discovery cohort
Planets confirmed in 2020 at Kepler (12 shown).
Host System: Kepler-1666
Spectral Class
F-type yellow-white
Effective Temperature
6,293 K — hotter than the Sun (5,778 K)
Estimated Age
0.41 Gyr — younger than the Sun (4.6 Gyr)
Stellar Radius
1.146 R☉
Stellar Mass
1.230 M☉
Metallicity [Fe/H]
-0.20
Extended Stellar Properties
Surface gravity (log g)
4.410 dex
Stellar density
1.153 g/cm³
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 16 bands
Astrometric Data
Parallax
0.697 mas
Total Proper Motion
2.568 mas/yr
PM Right Ascension
0.82 mas/yr
PM Declination
-2.43 mas/yr
Galactic Cartesian (pc)
x = 0.324 · y = -0.611 · z = 0.723
Equatorial (J2000)
RA 297.95161° · Dec 46.26470°
Galactic ℓ, b
80.302° · 9.745°
Ecliptic λ, β
319.895° · 64.936°
HTM-20 index
15392576
Similar Worlds
HD 73344 b
Sub-Neptune · F-type yellow-white
Radius 2.88 R⊕ · 115.0 ly
Kepler-1723 b
Sub-Neptune · F-type yellow-white
Radius 2.88 R⊕ · 2,646.0 ly
KOI-351 f
Sub-Neptune · F-type yellow-white
Radius 2.88 R⊕ · 2,766.6 ly
Kepler-805 b
Sub-Neptune · F-type yellow-white
Radius 2.89 R⊕ · 2,082.5 ly
Kepler-1921 b
Sub-Neptune · F-type yellow-white
Radius 2.89 R⊕ · 3,030.0 ly
Kepler-880 c
Sub-Neptune · F-type yellow-white
Radius 2.87 R⊕ · 1,961.3 ly