Key parameters at a glance
- A radius of 1.31 Earth radii
- A mass of 2.27 Earth masses
- Surface gravity around 1.32 g
- An orbital period of 1.923 days
- Semi-major axis 0.0290 AU
- Equilibrium temperature 1,215 K (942 °C)
- Distance from Earth 2,004.46 light-years
- Earth Similarity Index 0.250
- Travel time at Voyager 1 speed 35,348,653 years
- Almost certainly tidally locked to its host star given the close orbit
Kepler-821 b Planet Profile
Physical Specs
Classification
Planet Type
Super-Earth
Discovery
Size rank in cohort
Rank by radius
#1072of 1176
top 91.1%
This planet
1.31R⊕
Super-Earth median
1.60R⊕
Nearest-size peers
| Metric | Earth | Kepler-821 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 1.31 | 11.21 |
| Mass (M⊕) | 1.00 | 2.27 | 317.83 |
| Density (g/cm³) | 5.51 | 5.55 | 1.33 |
| Surface Gravity (g) | 1.00 | 1.32 | 2.53 |
| Insolation (S⊕) | 1.00 | 496.82 | 0.037 |
Star Catalogue Identifiers
TIC
TIC 120573482
Gaia DR2
Gaia DR2 2100279865772807424
Gaia DR3
Gaia DR3 2100279865772807424
System
Kepler-821
Percentile among Super-Earth cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 1.92 Earth days (0.5% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0290 AU.
Transit Fingerprint
Depth
0.026 %
Duration
1.919 h
Impact parameter b
0.133
Rp / R★
0.014745
Transit midpoint (BJD)
2,454,967.5034
Photometric dip
Transit produces a flux drop of 260 ppm lasting ≈ 1.92 h.
Extended Orbital Architecture
Planet / star radius ratio
0.014745
Semi-major axis / stellar radius
7.723
Impact parameter (b)
0.133
Transit mid-time (BJD)
2,454,967.5034
Angular separation (arcsec)
0.04720
Eq. Temperature
1,215K
(942 °C)
Insolation (S⊕)
496.82
Earth = 1.00
Earth Similarity (ESI)
0.250
0 = alien, 1 = Earth-identical
Inside the inner HZ boundary (too hot for liquid water) — the dayside is scorched. 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-821
Spectral Class
K-type orange
Effective Temperature
5,191 K — cooler than the Sun (5,778 K)
Estimated Age
4.79 Gyr — older than the Sun (4.6 Gyr)
Stellar Radius
0.800 R☉
Stellar Mass
0.840 M☉
Metallicity [Fe/H]
-0.03
Extended Stellar Properties
Surface gravity (log g)
4.560 dex
Stellar density
2.357 g/cm³
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 17 bands
Astrometric Data
Parallax
1.599 mas
Total Proper Motion
12.994 mas/yr
PM Right Ascension
-7.11 mas/yr
PM Declination
-10.87 mas/yr
Galactic Cartesian (pc)
x = 0.208 · y = -0.744 · z = 0.634
Equatorial (J2000)
RA 285.61739° · Dec 39.37947°
Galactic ℓ, b
69.923° · 14.845°
Ecliptic λ, β
295.787° · 61.428°
HTM-20 index
-524699046
Similar Worlds
Kepler-1254 d
Super-Earth · K-type orange
Radius 1.31 R⊕ · 2,031.4 ly
Kepler-62 b
Super-Earth · K-type orange
Radius 1.31 R⊕ · 981.3 ly
Kepler-354 c
Super-Earth · K-type orange
Radius 1.31 R⊕ · 1,807.1 ly
K2-233 b
Super-Earth · K-type orange
Radius 1.32 R⊕ · 220.2 ly
TOI-2076 e
Super-Earth · K-type orange
Radius 1.30 R⊕ · 136.7 ly
Kepler-1783 b
Super-Earth · K-type orange
Radius 1.32 R⊕ · 861.3 ly