Key parameters at a glance
- A radius of 3.07 Earth radii
- A mass of 9.64 Earth masses
- Surface gravity around 1.02 g
- An orbital period of 6.029 days
- Semi-major axis 0.0585 AU
- Equilibrium temperature 678 K (405 °C)
- Distance from Earth 1,744.24 light-years
- Earth Similarity Index 0.344
- Travel time at Voyager 1 speed 30,759,726 years
- Almost certainly tidally locked to its host star given the close orbit
Kepler-661 b Planet Profile
Physical Specs
Classification
Planet Type
Sub-Neptune
Discovery
Size rank in cohort
Rank by radius
#456of 1978
top 23.0%
This planet
3.07R⊕
Sub-Neptune median
2.71R⊕
Nearest-size peers
| Metric | Earth | Kepler-661 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 3.07 | 11.21 |
| Mass (M⊕) | 1.00 | 9.64 | 317.83 |
| Density (g/cm³) | 5.51 | 1.83 | 1.33 |
| Surface Gravity (g) | 1.00 | 1.02 | 2.53 |
| Insolation (S⊕) | 1.00 | 45.53 | 0.037 |
Star Catalogue Identifiers
TIC
TIC 164557360
Gaia DR2
Gaia DR2 2131635154256753408
Gaia DR3
Gaia DR3 2131635154256753408
System
Kepler-661
Percentile among Sub-Neptune cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 6.03 Earth days (1.7% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0585 AU.
Transit Fingerprint
Depth
0.191 %
Duration
1.580 h
Impact parameter b
0.890
Rp / R★
0.041510
Transit midpoint (BJD)
2,455,004.6033
Photometric dip
Transit produces a flux drop of 1,913 ppm lasting ≈ 1.58 h.
Extended Orbital Architecture
Planet / star radius ratio
0.041510
Semi-major axis / stellar radius
29.310
Impact parameter (b)
0.890
Transit mid-time (BJD)
2,455,004.6033
Angular separation (arcsec)
0.10900
Eq. Temperature
678K
(405 °C)
Insolation (S⊕)
45.53
Earth = 1.00
Earth Similarity (ESI)
0.344
0 = alien, 1 = Earth-identical
Inside the inner HZ boundary (too hot for liquid water) — the surface is too hot to retain surface water. Close-orbiting tidally-locked around a cool host.
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-661
Spectral Class
K-type orange
Effective Temperature
4,483 K — cooler than the Sun (5,778 K)
Estimated Age
4.27 Gyr — younger than the Sun (4.6 Gyr)
Stellar Radius
0.670 R☉
Stellar Mass
0.700 M☉
Metallicity [Fe/H]
-0.05
Extended Stellar Properties
Surface gravity (log g)
4.640 dex
Stellar density
13.098 g/cm³
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 16 bands
Astrometric Data
Parallax
1.842 mas
Total Proper Motion
28.550 mas/yr
PM Right Ascension
-19.71 mas/yr
PM Declination
-20.66 mas/yr
Galactic Cartesian (pc)
x = 0.159 · y = -0.652 · z = 0.742
Equatorial (J2000)
RA 283.71075° · Dec 47.86317°
Galactic ℓ, b
77.661° · 19.224°
Ecliptic λ, β
297.685° · 69.988°
HTM-20 index
1451174055
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