Confirmed Exoplanet Discovered 2018

K2-223 c

A super-earth orbiting the g-type yellow (sun-like) K2-223, located approximately 647.8 light-years from Earth.

Key parameters at a glance

  • A radius of 1.50 Earth radii
  • A mass of 2.86 Earth masses
  • Surface gravity around 1.27 g
  • An orbital period of 4.563 days
  • Semi-major axis 0.0549 AU
  • Equilibrium temperature 1,091 K (818 °C)
  • Distance from Earth 647.76 light-years
  • Earth Similarity Index 0.272
  • Travel time at Voyager 1 speed 11,423,227 years

1 sibling around K2-223

K2-223 c shares its host star with 1 other confirmed planet. Side-by-side measurements below.

Planet Type Radius (R⊕) Mass (M⊕) Period (d) Eq. T (K) Year
K2-223 b Rocky Terrestrial 0.89 0.64 0.506 2,271 2018
K2-223 c this Super-Earth 1.50 2.86 4.563 1,091 2018

K2-223 c Planet Profile

Physical Specs

Radius
1.50 R⊕
Radius (Jupiter)
0.134 R♃
Mass
2.86 M⊕
Mass (Jupiter)
0.009 M♃
Density
4.66 g/cm³
Surface Gravity
1.27 g (Earth)

Classification

Planet Type

Super-Earth

ESI Score 0.272
HZ Position Unknown
Controversial No

Discovery

Year 2018
Method Transit
Facility K2
Telescope 0.95 m Kepler Telescope

Size rank in cohort

Rank by radius

#748of 1176

top 63.5%

This planet

1.50R⊕

Super-Earth median

1.60R⊕

Nearest-size peers

Metric Earth K2-223 c Jupiter
Radius (R⊕)1.001.5011.21
Mass (M⊕)1.002.86317.83
Density (g/cm³)5.514.661.33
Surface Gravity (g)1.001.272.53
Insolation (S⊕)1.000.037

Star Catalogue Identifiers

TIC

TIC 98594138

Gaia DR2

Gaia DR2 3578046995560843520

Gaia DR3

Gaia DR3 3578046995560843520

System

K2-223

Percentile among Super-Earth cohort

Radius 1.500 R⊕ · percentile 35 / cohort 1176
Mass 2.860 M⊕ · percentile 33 / cohort 1176
Orbital period 4.56 d · percentile 37 / cohort 1164
Distance 198.60 pc · percentile 24 / cohort 1171
ESI 0.272 · percentile 30 / cohort 1176

Orbit & Habitability

Orbital Dynamics

Period
4.563 days
Semi-major axis
0.0549 AU
Eccentricity
Inclination
89.60 °

Year Length

A year here lasts approximately 4.56 Earth days (1.2% of a terrestrial year) at a mean orbital distance of 0.0549 AU.

Transit Fingerprint

Depth

0.020 %

Duration

2.800 h

Impact parameter b

0.420

Rp / R★

0.012900

Transit midpoint (BJD)

2,457,628.6121

Photometric dip

Transit produces a flux drop of 200 ppm lasting ≈ 2.80 h.

Extended Orbital Architecture

Planet / star radius ratio

0.012900

Semi-major axis / stellar radius

13.000

Impact parameter (b)

0.420

Transit mid-time (BJD)

2,457,628.6121

Angular separation (arcsec)

0.27600

Eq. Temperature

1,091K

(818 °C)

Insolation (S⊕)

Earth = 1.00

Earth Similarity (ESI)

0.272

0 = alien, 1 = Earth-identical

Insufficient insolation data — the dayside is scorched.

Discovery Paper

Primary reference

Mayo et al. 2018

Instrument

Kepler CCD Array

Publication

2018-03

Observation locale

Space

Host System: K2-223

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,859 K — hotter than the Sun (5,778 K)

Estimated Age

Stellar Radius

1.000 R☉

Stellar Mass

1.060 M☉

Metallicity [Fe/H]

0.19

Extended Stellar Properties

Surface gravity (log g)

4.500 dex

Stellar density

1.551 g/cm³

Systemic radial velocity

9.40 km/s

Metallicity ratio

[Fe/H]

Distance
198.60 parsec
Light-years 647.76 ly
V-band magnitude
11.44 mag
Voyager-speed travel 11,423,227 yr

Multi-band Host Photometry — 12 bands

8.512.112.13B11.44V11.27Gaia11.33Kepler10.82TESS10.18J9.95H9.84K9.80W19.83W29.51W38.47W4

Astrometric Data

Parallax

5.007 mas

Total Proper Motion

16.752 mas/yr

PM Right Ascension

7.38 mas/yr

PM Declination

-15.04 mas/yr

Galactic Cartesian (pc)

x = -0.980 · y = -0.091 · z = -0.178

Equatorial (J2000)

RA 185.30618° · Dec -10.28209°

Galactic ℓ, b

290.838° · 51.879°

Ecliptic λ, β

188.957° · -7.329°

HTM-20 index

2078357997

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