Key parameters at a glance
- A radius of 2.49 Earth radii
- A mass of 21.30 Earth masses
- Surface gravity around 3.44 g
- An orbital period of 5.070 days
- Semi-major axis 0.0598 AU
- Equilibrium temperature 1,372 K (1099 °C)
- Distance from Earth 1,676.04 light-years
- Earth Similarity Index 0.178
- Travel time at Voyager 1 speed 29,556,976 years
K2-66 b Planet Profile
Physical Specs
Classification
Planet Type
Sub-Neptune
Discovery
Size rank in cohort
Rank by radius
#1191of 1978
top 60.2%
This planet
2.49R⊕
Sub-Neptune median
2.71R⊕
Nearest-size peers
| Metric | Earth | K2-66 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 2.49 | 11.21 |
| Mass (M⊕) | 1.00 | 21.30 | 317.83 |
| Density (g/cm³) | 5.51 | 7.80 | 1.33 |
| Surface Gravity (g) | 1.00 | 3.44 | 2.53 |
| Insolation (S⊕) | 1.00 | 840.00 | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Best measured mass | 21.300 M⊕ | Direct mass measurement (not derived). |
Star Catalogue Identifiers
TIC
TIC 50183101
Gaia DR2
Gaia DR2 2614121364991061888
Gaia DR3
Gaia DR3 2614121364991061888
System
K2-66
Percentile among Sub-Neptune cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 5.07 Earth days (1.4% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0598 AU.
Transit Fingerprint
Depth
0.029 %
Duration
4.710 h
Impact parameter b
0.470
Rp / R★
0.013530
Transit midpoint (BJD)
2,456,984.0075
Photometric dip
Transit produces a flux drop of 288 ppm lasting ≈ 4.71 h.
Extended Orbital Architecture
Planet / star radius ratio
0.013530
Semi-major axis / stellar radius
7.874
Impact parameter (b)
0.470
RV semi-amplitude (K)
7.400 m/s
Transit mid-time (BJD)
2,456,984.0075
Angular separation (arcsec)
0.11600
Eq. Temperature
1,372K
(1099 °C)
Insolation (S⊕)
840.00
Earth = 1.00
Earth Similarity (ESI)
0.178
0 = alien, 1 = Earth-identical
Inside the inner HZ boundary (too hot for liquid water) — the dayside is scorched.
Detection Signatures
Transit photometry
A transit dip has been observed from at least one telescope.
Radial velocity
Stellar wobble has been measured spectroscopically.
Discovery Paper
Primary reference
Crossfield et al. 2016Instrument
Kepler CCD Array
Publication
2016-09
Observation locale
Space
Discovery cohort
Planets confirmed in 2016 at K2 (12 shown).
Host System: K2-66
Spectral Class
G-type yellow (Sun-like)
Effective Temperature
5,887 K — hotter than the Sun (5,778 K)
Estimated Age
—
Stellar Radius
1.670 R☉
Stellar Mass
1.110 M☉
Metallicity [Fe/H]
-0.05
Extended Stellar Properties
Surface gravity (log g)
4.030 dex
Stellar density
0.299 g/cm³
Systemic radial velocity
46.24 km/s
Rotational v·sin i
3.70 km/s
Activity index (log R'HK)
-5.267
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 12 bands
Astrometric Data
Parallax
1.921 mas
Total Proper Motion
8.084 mas/yr
PM Right Ascension
-4.32 mas/yr
PM Declination
-6.83 mas/yr
Galactic Cartesian (pc)
x = 0.864 · y = -0.468 · z = -0.186
Equatorial (J2000)
RA 331.52666° · Dec -10.71154°
Galactic ℓ, b
47.695° · -47.850°
Ecliptic λ, β
329.746° · 0.906°
HTM-20 index
-667201292
Similar Worlds
HD 88986 b
Sub-Neptune · G-type yellow (Sun-like)
Radius 2.49 R⊕ · 108.5 ly
Kepler-109 b
Sub-Neptune · G-type yellow (Sun-like)
Radius 2.49 R⊕ · 1,548.8 ly
Kepler-265 d
Sub-Neptune · G-type yellow (Sun-like)
Radius 2.49 R⊕ · 4,175.6 ly
Kepler-184 d
Sub-Neptune · G-type yellow (Sun-like)
Radius 2.49 R⊕ · 1,990.6 ly
Kepler-11 f
Sub-Neptune · G-type yellow (Sun-like)
Radius 2.49 R⊕ · 2,108.1 ly
Kepler-289 b
Sub-Neptune · G-type yellow (Sun-like)
Radius 2.49 R⊕ · 2,297.6 ly