Key parameters at a glance
- A radius of 2.65 Earth radii
- A mass of 7.51 Earth masses
- Surface gravity around 1.07 g
- An orbital period of 9.796 days
- Semi-major axis 0.0785 AU
- Equilibrium temperature 542 K (269 °C)
- Distance from Earth 356.22 light-years
- Earth Similarity Index 0.452
- Travel time at Voyager 1 speed 6,281,958 years
- Almost certainly tidally locked to its host star given the close orbit
K2-212 b Planet Profile
Physical Specs
Classification
Planet Type
Sub-Neptune
Discovery
Size rank in cohort
Rank by radius
#946of 1978
top 47.8%
This planet
2.65R⊕
Sub-Neptune median
2.71R⊕
Nearest-size peers
| Metric | Earth | K2-212 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 2.65 | 11.21 |
| Mass (M⊕) | 1.00 | 7.51 | 317.83 |
| Density (g/cm³) | 5.51 | 2.22 | 1.33 |
| Surface Gravity (g) | 1.00 | 1.07 | 2.53 |
| Insolation (S⊕) | 1.00 | 21.96 | 0.037 |
Star Catalogue Identifiers
TIC
TIC 388811663
Gaia DR2
Gaia DR2 2538824923230146560
Gaia DR3
Gaia DR3 2538824923230146560
System
K2-212
Percentile among Sub-Neptune cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 9.80 Earth days (2.7% of a terrestrial year) at a mean orbital distance of 0.0785 AU.
Transit Fingerprint
Depth
0.128 %
Duration
2.599 h
Impact parameter b
0.420
Rp / R★
0.035770
Transit midpoint (BJD)
2,457,399.6411
Photometric dip
Transit produces a flux drop of 1,280 ppm lasting ≈ 2.60 h.
Extended Orbital Architecture
Planet / star radius ratio
0.035770
Semi-major axis / stellar radius
27.970
Impact parameter (b)
0.420
Transit mid-time (BJD)
2,457,399.6411
Angular separation (arcsec)
0.71900
Eq. Temperature
542K
(269 °C)
Insolation (S⊕)
21.96
Earth = 1.00
Earth Similarity (ESI)
0.452
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
Mayo et al. 2018Instrument
Kepler CCD Array
Publication
2018-03
Observation locale
Space
Discovery cohort
Planets confirmed in 2018 at K2 (12 shown).
Host System: K2-212
Spectral Class
K-type orange
Effective Temperature
4,349 K — cooler than the Sun (5,778 K)
Estimated Age
—
Stellar Radius
0.678 R☉
Stellar Mass
0.622 M☉
Metallicity [Fe/H]
0.03
Extended Stellar Properties
Surface gravity (log g)
4.720 dex
Stellar density
4.445 g/cm³
Systemic radial velocity
-6.84 km/s
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 17 bands
Astrometric Data
Parallax
9.128 mas
Total Proper Motion
165.672 mas/yr
PM Right Ascension
162.64 mas/yr
PM Declination
31.58 mas/yr
Galactic Cartesian (pc)
x = 0.947 · y = 0.316 · z = 0.054
Equatorial (J2000)
RA 18.42410° · Dec 3.09707°
Galactic ℓ, b
133.865° · -59.301°
Ecliptic λ, β
18.172° · -4.357°
HTM-20 index
1885426141
Similar Worlds
HD 39194 c
Sub-Neptune · K-type orange
Radius 2.65 R⊕ · 86.1 ly
TOI-277 b
Sub-Neptune · K-type orange
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TOI-1064 c
Sub-Neptune · K-type orange
Radius 2.65 R⊕ · 222.0 ly
K2-165 d
Sub-Neptune · K-type orange
Radius 2.65 R⊕ · 439.0 ly
Kepler-1822 b
Sub-Neptune · K-type orange
Radius 2.65 R⊕ · 2,927.6 ly
Kepler-1110 b
Sub-Neptune · K-type orange
Radius 2.66 R⊕ · 2,370.6 ly