Kepler-1658
Triple star system in the constellation Cygnus
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Kepler-1658 is a triple star system located in the constellation Cygnus.[1] Based on parallax measurements by the Gaia spacecraft,[2] it is located at a distance of 2,660 light-years (820 parsecs).
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Cygnus[1] |
| Right ascension | 18h 46m 22.24188s[2] |
| Declination | +75° 26′ 02.2400″[2] |
| Apparent magnitude (V) | 11.556±0.100[3] |
| Characteristics | |
| A | |
| Evolutionary stage | Subgiant[4] |
| Spectral type | F5[5] |
| BC | |
| Evolutionary stage | main sequence[6] |
| Spectral type | KV + MV[6] |
| Variable type | eclipsing binary[6] |
| Astrometry | |
| Radial velocity (Rv) | −21.815±0.053[7] km/s |
| Proper motion (μ) | RA: +0.100 mas/yr[2] Dec.: −5.542 mas/yr[2] |
| Parallax (π) | 1.2260±0.0173 mas[2] |
| Distance | 2,660 ± 40 ly (820 ± 10 pc) |
| Orbit[6] | |
| Primary | A |
| Name | BC |
| Semi-major axis (a) | 50 AU |
| Orbit[6] | |
| Primary | B |
| Name | C |
| Period (P) | 3.849363145 days |
| Details[8] | |
| Kepler-1658 A | |
| Mass | 1.45±0.03 M☉ |
| Radius | 3.26±0.14 R☉ |
| Surface gravity (log g) | 4.13±0.05 cgs |
| Temperature | 5,948±100 K |
| Metallicity [Fe/H] | −0.27±0.06 dex |
| Rotational velocity (v sin i) | 38 km/s |
| Age | 2.0±0.1 Gyr |
| Kepler-1658 B | |
| Mass | 0.75[6] M☉ |
| Kepler-1658 C | |
| Mass | 0.19[6] M☉ |
| Radius | 0.23[6] R☉ |
| Other designations | |
| KOI-4, KIC 3861595, TIC 377873569, TYC 3135-652-1[9] | |
| Database references | |
| SIMBAD | data |
This is an hierarchical triple system whose primary is an F-type subgiant star with 1.45 times the Sun's mass and 3.26 times the Sun's radius.[8] The outer system, 50 astronomical units away from the primary, is an eclipsing binary whose components have an orbital period of 3.8 days: star B is probably a K-type dwarf with 0.8 times the Sun's mass, and star C a red dwarf with 0.19 times the mass of the Sun and 0.23 times the radius.[6]
Search for planets
In 2009, a hot Jupiter planet candidate (KOI-4.01, now known as Kepler-1658b) was identified around Kepler-1658 by the Kepler space telescope via the transit method. Initially ruled out as a false alarm, a 2019 study re-claimed its nature as a planet. This would be the first planet ever detected by Kepler.[4] Analysis of the Transiting Exoplanet Survey Satellite (TESS) data in 2022 showed that it is gradually spiraling into its star, with its orbit decaying.[10] However, in 2025 it was demonstrated that Kepler-1658b is a false positive planet.[6] In reality, all the data that supported the detection of a planet with physical orbital decay were caused by the eclipsing outer system, whose light travel time effect is responsible for the supposed orbital decay.[6]