Kepler-223
G5V star in the constellation Cygnus
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Kepler-223 (KOI-730, KIC 10227020) is a G8 star with an extrasolar planetary system discovered by the Kepler mission. Studies indicate that the Kepler-223 star system consists of 4 planets orbiting the star.[9][10]
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Cygnus[1] |
| Right ascension | 19h 53m 16.4202s[2] |
| Declination | +47° 16′ 46.308″[2] |
| Apparent magnitude (V) | 15.3[3] |
| Characteristics | |
| Evolutionary stage | subgiant[2] |
| Spectral type | G8[3] |
| Apparent magnitude (g) | 15.903[4] |
| Apparent magnitude (r) | 15.301[4] |
| Apparent magnitude (i) | 15.105[4] |
| Apparent magnitude (z) | 14.963[4] |
| Apparent magnitude (D51) | 15.667[4] |
| Apparent magnitude (J) | 14.095[4] |
| Apparent magnitude (H) | 13.727[4] |
| Apparent magnitude (K) | 13.632[4] |
| J−K color index | 0.463[4] |
| Astrometry | |
| Proper motion (μ) | RA: −4.227(25) mas/yr[2] Dec.: −11.094(24) mas/yr[2] |
| Parallax (π) | 0.5005±0.0215 mas[2] |
| Distance | 6,500 ± 300 ly (2,000 ± 90 pc) |
| Details | |
| Mass | 1.04[5] M☉ |
| Radius | 1.52[5] R☉ |
| Surface gravity (log g) | 4.09[5] cgs |
| Temperature | 5,803[5] K |
| Metallicity [Fe/H] | −0.211[4] dex |
| Rotation | 17.82 days[6] |
| Rotational velocity (v sin i) | 2.4[7] km/s |
| Age | 3.7[7] Gyr |
| Other designations | |
| KOI-730, KIC 10227020, 2MASS J195316.40+471646.1[8] | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
| KIC | data |
Planetary system
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | — | — | 7.3845 | — | — | 3 R🜨 |
| c | — | — | 9.8456 | — | — | 3.4 R🜨 |
| d | — | — | 14.7887 | — | — | 5.2 R🜨 |
| e | — | — | 19.7257 | — | — | 4.6 R🜨 |
The confirmed planetary system was first detected by the Kepler mission, and contains four planets.[11] This system was initially believed to contain two co-orbital planets orbiting the star at approximately the same orbital distance every 9.8 days, with one permanently locked 60° behind the other in one of the two Trojan Lagrangian points.[12] The two co-orbital planets were thought to be locked in mean motion resonances with the other two planets, creating an overall 6:4:4:3 resonance.[13] This would have been the first known example of co-orbital planets.
However, follow-up study of the system revealed that an alternative configuration, with the four planets having orbital periods in the ratio 8:6:4:3 is better supported by the data. This configuration does not contain co-orbital planets,[14] and has been confirmed by further observations.[10] It represents the first confirmed 4-body orbital resonance.[11]
The radii are 3.0, 3.4, 5.2, and 4.6 Earth radii, and the orbital periods are 7.3845, 9.8456, 14.7887 and 19.7257 days, respectively.[10]
Kepler-223 6:4:4:3 orbital ratios
Kepler-223 8:6:4:3 orbital ratios
