Key parameters at a glance
- A radius of 2.09 Earth radii
- A mass of 5.02 Earth masses
- Surface gravity around 1.15 g
- An orbital period of 8.114 days
- Semi-major axis 0.0649 AU
- Equilibrium temperature 460 K (187 °C)
- Distance from Earth 910.35 light-years
- Earth Similarity Index 0.570
- Travel time at Voyager 1 speed 16,054,027 years
- Almost certainly tidally locked to its host star given the close orbit
Kepler-691 b Planet Profile
Physical Specs
Classification
Planet Type
Sub-Neptune
Discovery
Size rank in cohort
Rank by radius
#1832of 1978
top 92.6%
This planet
2.09R⊕
Sub-Neptune median
2.71R⊕
Nearest-size peers
| Metric | Earth | Kepler-691 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 2.09 | 11.21 |
| Mass (M⊕) | 1.00 | 5.02 | 317.83 |
| Density (g/cm³) | 5.51 | 3.02 | 1.33 |
| Surface Gravity (g) | 1.00 | 1.15 | 2.53 |
| Insolation (S⊕) | 1.00 | 13.00 | 0.037 |
Star Catalogue Identifiers
TIC
TIC 121787669
Gaia DR2
Gaia DR2 2101242934881164416
Gaia DR3
Gaia DR3 2101242934881164416
System
Kepler-691
Percentile among Sub-Neptune cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 8.11 Earth days (2.2% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0649 AU.
Transit Fingerprint
Depth
0.156 %
Duration
2.258 h
Impact parameter b
0.057
Rp / R★
0.037670
Transit midpoint (BJD)
2,455,009.3393
Photometric dip
Transit produces a flux drop of 1,558 ppm lasting ≈ 2.26 h.
Extended Orbital Architecture
Planet / star radius ratio
0.037670
Semi-major axis / stellar radius
28.450
Impact parameter (b)
0.057
Transit mid-time (BJD)
2,455,009.3393
Angular separation (arcsec)
0.23300
Eq. Temperature
460K
(187 °C)
Insolation (S⊕)
13.00
Earth = 1.00
Earth Similarity (ESI)
0.570
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-691
Spectral Class
K-type orange
Effective Temperature
3,715 K — cooler than the Sun (5,778 K)
Estimated Age
3.98 Gyr — younger than the Sun (4.6 Gyr)
Stellar Radius
0.500 R☉
Stellar Mass
0.530 M☉
Metallicity [Fe/H]
0.04
Extended Stellar Properties
Surface gravity (log g)
4.760 dex
Stellar density
4.378 g/cm³
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 16 bands
Astrometric Data
Parallax
3.555 mas
Total Proper Motion
58.668 mas/yr
PM Right Ascension
-45.79 mas/yr
PM Declination
-36.67 mas/yr
Galactic Cartesian (pc)
x = 0.247 · y = -0.725 · z = 0.643
Equatorial (J2000)
RA 288.81173° · Dec 40.03323°
Galactic ℓ, b
71.566° · 12.864°
Ecliptic λ, β
301.108° · 61.456°
HTM-20 index
-1000567031
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