Key parameters at a glance
- A radius of 3.08 Earth radii
- A mass of 9.69 Earth masses
- Surface gravity around 1.02 g
- An orbital period of 26.394 days
- Semi-major axis 0.1635 AU
- Equilibrium temperature 489 K (216 °C)
- Distance from Earth 2,240.44 light-years
- Earth Similarity Index 0.466
- Travel time at Voyager 1 speed 39,510,167 years
- Almost certainly tidally locked to its host star given the close orbit
Kepler-681 b Planet Profile
Physical Specs
Classification
Planet Type
Sub-Neptune
Discovery
Size rank in cohort
Rank by radius
#448of 1978
top 22.6%
This planet
3.08R⊕
Sub-Neptune median
2.71R⊕
Nearest-size peers
| Metric | Earth | Kepler-681 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 3.08 | 11.21 |
| Mass (M⊕) | 1.00 | 9.69 | 317.83 |
| Density (g/cm³) | 5.51 | 1.82 | 1.33 |
| Surface Gravity (g) | 1.00 | 1.02 | 2.53 |
| Insolation (S⊕) | 1.00 | 14.15 | 0.037 |
Star Catalogue Identifiers
TIC
TIC 299217986
Gaia DR2
Gaia DR2 2133249099888182912
Gaia DR3
Gaia DR3 2133249099888182912
System
Kepler-681
Percentile among Sub-Neptune cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 26.39 Earth days (7.2% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.1635 AU.
Transit Fingerprint
Depth
0.151 %
Duration
3.479 h
Impact parameter b
0.130
Rp / R★
0.037396
Transit midpoint (BJD)
2,455,009.0536
Photometric dip
Transit produces a flux drop of 1,511 ppm lasting ≈ 3.48 h.
Extended Orbital Architecture
Planet / star radius ratio
0.037396
Semi-major axis / stellar radius
59.660
Impact parameter (b)
0.130
Transit mid-time (BJD)
2,455,009.0536
Angular separation (arcsec)
0.23800
Eq. Temperature
489K
(216 °C)
Insolation (S⊕)
14.15
Earth = 1.00
Earth Similarity (ESI)
0.466
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-681
Spectral Class
K-type orange
Effective Temperature
5,021 K — cooler than the Sun (5,778 K)
Estimated Age
5.01 Gyr — older than the Sun (4.6 Gyr)
Stellar Radius
0.760 R☉
Stellar Mass
0.800 M☉
Metallicity [Fe/H]
-0.04
Extended Stellar Properties
Surface gravity (log g)
4.580 dex
Stellar density
5.766 g/cm³
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 16 bands
Astrometric Data
Parallax
1.427 mas
Total Proper Motion
20.334 mas/yr
PM Right Ascension
0.72 mas/yr
PM Declination
-20.32 mas/yr
Galactic Cartesian (pc)
x = 0.208 · y = -0.590 · z = 0.780
Equatorial (J2000)
RA 289.39974° · Dec 51.25024°
Galactic ℓ, b
82.374° · 16.988°
Ecliptic λ, β
311.929° · 71.874°
HTM-20 index
43868507
Similar Worlds
TOI-1180 b
Sub-Neptune · K-type orange
Radius 3.07 R⊕ · 234.9 ly
Kepler-859 b
Sub-Neptune · K-type orange
Radius 3.09 R⊕ · 2,739.4 ly
Kepler-661 b
Sub-Neptune · K-type orange
Radius 3.07 R⊕ · 1,744.2 ly
Kepler-563 b
Sub-Neptune · K-type orange
Radius 3.09 R⊕ · 1,843.5 ly
Kepler-749 b
Sub-Neptune · K-type orange
Radius 3.10 R⊕ · 2,351.7 ly
TOI-1410.01
Sub-Neptune · K-type orange
Radius 3.10 R⊕ · 237.3 ly