Key parameters at a glance
- A radius of 1.27 Earth radii
- A mass of 4.60 Earth masses
- Surface gravity around 2.84 g
- An orbital period of 7.060 days
- Semi-major axis 0.0664 AU
- Equilibrium temperature 794 K (521 °C)
- Distance from Earth 220.18 light-years
- Earth Similarity Index 0.335
- Travel time at Voyager 1 speed 3,882,795 years
- Almost certainly tidally locked to its host star given the close orbit
2 siblings around K2-233
K2-233 c shares its host star with 2 other confirmed planets. Side-by-side measurements below.
K2-233 c Planet Profile
Physical Specs
Classification
Planet Type
Super-Earth
Discovery
Size rank in cohort
Rank by radius
#1133of 1176
top 96.3%
This planet
1.27R⊕
Super-Earth median
1.60R⊕
Nearest-size peers
| Metric | Earth | K2-233 c | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 1.27 | 11.21 |
| Mass (M⊕) | 1.00 | 4.60 | 317.83 |
| Density (g/cm³) | 5.51 | 12.40 | 1.33 |
| Surface Gravity (g) | 1.00 | 2.84 | 2.53 |
| Insolation (S⊕) | 1.00 | 66.20 | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Best measured mass | 4.600 M⊕ | Direct mass measurement (not derived). |
Star Catalogue Identifiers
TIC
TIC 428820090
Gaia DR2
Gaia DR2 6253186686054822784
Gaia DR3
Gaia DR3 6253186686054822784
System
K2-233
Percentile among Super-Earth cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 7.06 Earth days (1.9% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0664 AU.
Transit Fingerprint
Duration
2.687 h
Impact parameter b
0.150
Rp / R★
0.016420
Transit midpoint (BJD)
2,457,586.8620
Extended Orbital Architecture
Planet / star radius ratio
0.016420
Semi-major axis / stellar radius
20.100
Impact parameter (b)
0.150
RV semi-amplitude (K)
1.810 m/s
Transit mid-time (BJD)
2,457,586.8620
Long. of periastron (ω)
90.00°
Angular separation (arcsec)
0.98400
Eq. Temperature
794K
(521 °C)
Insolation (S⊕)
66.20
Earth = 1.00
Earth Similarity (ESI)
0.335
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.
Detection Signatures
Transit photometry
A transit dip has been observed from at least one telescope.
Radial velocity
Stellar wobble has been measured spectroscopically.
Discovery Paper
Primary reference
David et al. 2018Instrument
Kepler CCD Array
Publication
2018-05
Observation locale
Space
Discovery cohort
Planets confirmed in 2018 at K2 (12 shown).
Host System: K2-233
Spectral Class
K-type orange
Effective Temperature
4,796 K — cooler than the Sun (5,778 K)
Estimated Age
0.36 Gyr — younger than the Sun (4.6 Gyr)
Stellar Radius
0.710 R☉
Stellar Mass
0.790 M☉
Metallicity [Fe/H]
-0.08
Extended Stellar Properties
Surface gravity (log g)
4.530 dex
Stellar density
3.080 g/cm³
Systemic radial velocity
-9.65 km/s
Rotational v·sin i
4.50 km/s
Rotation period
9.75 days
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 12 bands
Astrometric Data
Parallax
14.785 mas
Total Proper Motion
36.981 mas/yr
PM Right Ascension
-19.87 mas/yr
PM Declination
-31.19 mas/yr
Galactic Cartesian (pc)
x = -0.597 · y = -0.724 · z = -0.346
Equatorial (J2000)
RA 230.47990° · Dec -20.23180°
Galactic ℓ, b
344.464° · 30.249°
Ecliptic λ, β
233.316° · -1.683°
HTM-20 index
-1997526897
Similar Worlds
TOI-833 b
Super-Earth · K-type orange
Radius 1.27 R⊕ · 136.1 ly
K2-165 b
Super-Earth · K-type orange
Radius 1.27 R⊕ · 439.0 ly
K2-203 b
Super-Earth · K-type orange
Radius 1.27 R⊕ · 541.9 ly
Kepler-1037 b
Super-Earth · K-type orange
Radius 1.28 R⊕ · 1,457.6 ly
Kepler-787 b
Super-Earth · K-type orange
Radius 1.28 R⊕ · 1,642.4 ly
Kepler-776 b
Super-Earth · K-type orange
Radius 1.28 R⊕ · 2,374.1 ly