Key parameters at a glance
- A radius of 2.82 Earth radii
- A mass of 324.00 Earth masses
- Surface gravity around 40.74 g
- An orbital period of 14.646 days
- Semi-major axis 0.1170 AU
- Equilibrium temperature 694 K (421 °C)
- Distance from Earth 5,692.89 light-years
- Earth Similarity Index 0.204
- Travel time at Voyager 1 speed 100,394,108 years
2 siblings around Kepler-281
Kepler-281 b shares its host star with 2 other confirmed planets. Side-by-side measurements below.
| Planet | Type | Radius (R⊕) | Mass (M⊕) | Period (d) | Eq. T (K) | Year |
|---|---|---|---|---|---|---|
| Kepler-281 b this | Sub-Neptune | 2.82 | 324.00 | 14.646 | 694 | 2014 |
| Kepler-281 c | Neptune-like | 5.31 | 161.12 | 36.337 | 513 | 2014 |
| Kepler-281 d | Neptune-like | 5.94 | 654.00 | 148.272 | 321 | 2021 |
Kepler-281 b Planet Profile
Physical Specs
Classification
Planet Type
Sub-Neptune
Discovery
Size rank in cohort
Rank by radius
#720of 1978
top 36.3%
This planet
2.82R⊕
Sub-Neptune median
2.71R⊕
Nearest-size peers
| Metric | Earth | Kepler-281 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 2.82 | 11.21 |
| Mass (M⊕) | 1.00 | 324.00 | 317.83 |
| Density (g/cm³) | 5.51 | 52.00 | 1.33 |
| Surface Gravity (g) | 1.00 | 40.74 | 2.53 |
| Insolation (S⊕) | 1.00 | 118.25 | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Best measured mass | 324.000 M⊕ | Direct mass measurement (not derived). |
Star Catalogue Identifiers
TIC
TIC 270858032
Gaia DR2
Gaia DR2 2078404532186285568
Gaia DR3
Gaia DR3 2078404532186285568
System
Kepler-281
Percentile among Sub-Neptune cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 14.65 Earth days (4.0% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.1170 AU.
Transit Fingerprint
Depth
0.059 %
Duration
6.293 h
Impact parameter b
0.920
Rp / R★
0.023960
Transit midpoint (BJD)
2,454,969.5169
Photometric dip
Transit produces a flux drop of 594 ppm lasting ≈ 6.29 h.
Extended Orbital Architecture
Planet / star radius ratio
0.023960
Semi-major axis / stellar radius
15.800
Impact parameter (b)
0.920
Transit mid-time (BJD)
2,454,969.5169
Angular separation (arcsec)
0.06700
Eq. Temperature
694K
(421 °C)
Insolation (S⊕)
118.25
Earth = 1.00
Earth Similarity (ESI)
0.204
0 = alien, 1 = Earth-identical
Inside the inner HZ boundary (too hot for liquid water) — the surface is too hot to retain surface water.
Discovery Paper
Primary reference
Rowe et al. 2014Instrument
Kepler CCD Array
Publication
2014-03
Observation locale
Space
Discovery cohort
Planets confirmed in 2014 at Kepler (12 shown).
Host System: Kepler-281
Spectral Class
G-type yellow (Sun-like)
Effective Temperature
5,723 K — cooler than the Sun (5,778 K)
Estimated Age
0.60 Gyr — younger than the Sun (4.6 Gyr)
Stellar Radius
0.899 R☉
Stellar Mass
0.950 M☉
Metallicity [Fe/H]
0.02
Extended Stellar Properties
Surface gravity (log g)
4.531 dex
Stellar density
0.248 g/cm³
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 16 bands
Astrometric Data
Parallax
0.545 mas
Total Proper Motion
11.298 mas/yr
PM Right Ascension
-6.44 mas/yr
PM Declination
-9.29 mas/yr
Galactic Cartesian (pc)
x = 0.290 · y = -0.648 · z = 0.704
Equatorial (J2000)
RA 294.10815° · Dec 44.77065°
Galactic ℓ, b
77.669° · 11.413°
Ecliptic λ, β
312.683° · 64.678°
HTM-20 index
-1670214005
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