Key parameters at a glance
- A radius of 2.78 Earth radii
- A mass of 8.15 Earth masses
- Surface gravity around 1.05 g
- An orbital period of 4.795 days
- Semi-major axis 0.0477 AU
- Equilibrium temperature 653 K (380 °C)
- Distance from Earth 349.87 light-years
- Earth Similarity Index 0.372
- Travel time at Voyager 1 speed 6,170,029 years
- Almost certainly tidally locked to its host star given the close orbit
K2-284 b Planet Profile
Physical Specs
Classification
Planet Type
Sub-Neptune
Discovery
Size rank in cohort
Rank by radius
#768of 1978
top 38.8%
This planet
2.78R⊕
Sub-Neptune median
2.71R⊕
Nearest-size peers
| Metric | Earth | K2-284 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 2.78 | 11.21 |
| Mass (M⊕) | 1.00 | 8.15 | 317.83 |
| Density (g/cm³) | 5.51 | 2.08 | 1.33 |
| Surface Gravity (g) | 1.00 | 1.05 | 2.53 |
| Insolation (S⊕) | 1.00 | 42.60 | 0.037 |
Star Catalogue Identifiers
TIC
TIC 5882269
Gaia DR2
Gaia DR2 3413793491812093824
Gaia DR3
Gaia DR3 3413793491812093824
System
K2-284
Percentile among Sub-Neptune cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 4.80 Earth days (1.3% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0477 AU.
Transit Fingerprint
Depth
0.228 %
Duration
2.147 h
Impact parameter b
0.280
Rp / R★
0.042000
Transit midpoint (BJD)
2,457,859.1132
Photometric dip
Transit produces a flux drop of 2,280 ppm lasting ≈ 2.15 h.
Extended Orbital Architecture
Planet / star radius ratio
0.042000
Semi-major axis / stellar radius
16.840
Impact parameter (b)
0.280
Transit mid-time (BJD)
2,457,859.1132
Long. of periastron (ω)
180.20°
Angular separation (arcsec)
0.44500
Eq. Temperature
653K
(380 °C)
Insolation (S⊕)
42.60
Earth = 1.00
Earth Similarity (ESI)
0.372
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
David et al. 2018Instrument
Kepler CCD Array
Publication
2018-12
Observation locale
Space
Discovery cohort
Planets confirmed in 2018 at K2 (12 shown).
Host System: K2-284
Spectral Class
K-type orange
Effective Temperature
4,140 K — cooler than the Sun (5,778 K)
Estimated Age
0.12 Gyr — younger than the Sun (4.6 Gyr)
Stellar Radius
0.607 R☉
Stellar Mass
0.630 M☉
Metallicity [Fe/H]
0.00
Extended Stellar Properties
Surface gravity (log g)
4.670 dex
Stellar density
3.910 g/cm³
Systemic radial velocity
16.96 km/s
Rotational v·sin i
3.54 km/s
Rotation period
8.88 days
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 15 bands
Astrometric Data
Parallax
9.293 mas
Total Proper Motion
52.301 mas/yr
PM Right Ascension
25.00 mas/yr
PM Declination
-45.94 mas/yr
Galactic Cartesian (pc)
x = 0.177 · y = 0.921 · z = 0.346
Equatorial (J2000)
RA 79.14080° · Dec 20.25490°
Galactic ℓ, b
183.724° · -10.253°
Ecliptic λ, β
79.804° · -2.801°
HTM-20 index
1462152007
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