Key parameters at a glance
- A radius of 1.27 Earth radii
- A mass of 2.14 Earth masses
- Surface gravity around 1.34 g
- An orbital period of 9.695 days
- Semi-major axis 0.0824 AU
- Equilibrium temperature 738 K (465 °C)
- Distance from Earth 541.90 light-years
- Earth Similarity Index 0.425
- Travel time at Voyager 1 speed 9,556,378 years
- Almost certainly tidally locked to its host star given the close orbit
K2-203 b Planet Profile
Physical Specs
Classification
Planet Type
Super-Earth
Discovery
Size rank in cohort
Rank by radius
#1146of 1176
top 97.4%
This planet
1.27R⊕
Super-Earth median
1.60R⊕
Nearest-size peers
| Metric | Earth | K2-203 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 1.27 | 11.21 |
| Mass (M⊕) | 1.00 | 2.14 | 317.83 |
| Density (g/cm³) | 5.51 | 5.80 | 1.33 |
| Surface Gravity (g) | 1.00 | 1.34 | 2.53 |
| Insolation (S⊕) | 1.00 | — | 0.037 |
Star Catalogue Identifiers
TIC
TIC 333605244
Gaia DR2
Gaia DR2 2535901287452166400
Gaia DR3
Gaia DR3 2535901287452166400
System
K2-203
Percentile among Super-Earth cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 9.70 Earth days (2.7% of a terrestrial year) on a mildly elliptical path at a mean orbital distance of 0.0824 AU.
Transit Fingerprint
Depth
0.023 %
Duration
3.103 h
Impact parameter b
0.330
Rp / R★
0.015180
Transit midpoint (BJD)
2,457,435.4189
Photometric dip
Transit produces a flux drop of 230 ppm lasting ≈ 3.10 h.
Extended Orbital Architecture
Planet / star radius ratio
0.015180
Semi-major axis / stellar radius
23.160
Impact parameter (b)
0.330
Transit mid-time (BJD)
2,457,435.4189
Long. of periastron (ω)
-124.00°
Angular separation (arcsec)
0.49600
Eq. Temperature
738K
(465 °C)
Insolation (S⊕)
—
Earth = 1.00
Earth Similarity (ESI)
0.425
0 = alien, 1 = Earth-identical
Insufficient insolation data — 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: K2-203
Spectral Class
K-type orange
Effective Temperature
5,026 K — cooler than the Sun (5,778 K)
Estimated Age
6.90 Gyr — older than the Sun (4.6 Gyr)
Stellar Radius
0.765 R☉
Stellar Mass
0.793 M☉
Metallicity [Fe/H]
-0.02
Extended Stellar Properties
Surface gravity (log g)
4.570 dex
Stellar density
2.500 g/cm³
Systemic radial velocity
20.19 km/s
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 17 bands
Astrometric Data
Parallax
5.991 mas
Total Proper Motion
11.247 mas/yr
PM Right Ascension
-11.23 mas/yr
PM Declination
0.60 mas/yr
Galactic Cartesian (pc)
x = 0.975 · y = 0.221 · z = -0.021
Equatorial (J2000)
RA 12.77369° · Dec -1.19588°
Galactic ℓ, b
122.736° · -64.068°
Ecliptic λ, β
11.278° · -6.147°
HTM-20 index
685497431
Similar Worlds
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Super-Earth · K-type orange
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TOI-5789 b
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Kepler-1029 b
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Kepler-211 b
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