Theta Cygni
Theta Cygni (θ Cygni, θ Cyg) is a star in the northern constellation of Cygnus. It has an apparent visual magnitude of 4.5, so it can be seen from the northern hemisphere with the naked eye in sufficiently dark skies. Based upon parallax measurements, it is at a distance of about 59.8 light-years (18.3 parsecs) from the Earth. It is suspected of hosting an extrasolar planet.
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Cygnus |
| Right ascension | 19h 36m 26.53436s |
| Declination | +50° 13′ 15.9646″ |
| Apparent magnitude (V) | 4.490/13.03 |
| Characteristics | |
| Spectral type | F3 V + M3 V |
| U−B color index | –0.03 |
| B−V color index | +0.38 |
| Astrometry | |
| Radial velocity (Rv) | –27.4 km/s |
| Proper motion (μ) | RA: –8.87 mas/yr Dec.: +262.45 mas/yr |
| Parallax (π) | 54.54 ± 0.15 mas |
| Distance | 59.8 ± 0.2 ly (18.34 ± 0.05 pc) |
| Absolute magnitude (MV) | 3.14 |
| Details | |
| θ Cyg A | |
| Mass | 1.35 - 1.39 M☉ |
| Radius | 1.49±0.002 R☉ |
| Luminosity | 4.265±0.090 L☉ |
| Surface gravity (log g) | 4.23±0.03 cgs |
| Temperature | 6697±78 K |
| Metallicity [Fe/H] | −0.02±0.06 dex |
| Rotational velocity (v sin i) | 7 km/s |
| Age | 1.0 - 1.6 Gyr |
| θ Cyg B | |
| Mass | 0.35 M☉ |
| Radius | 0.36 R☉ |
| Luminosity | 0.01 L☉ |
| Temperature | 3,000 - 3,500 K |
| GSC 03564-00642 | |
| Radius | 0.28 R☉ |
| Luminosity | 0.013 L☉ |
| Temperature | 3,700 K |
| Other designations | |
| B: 2MASS 19362771+5013419, KIC 11918644 | |
| GJ 765B: 2MASS 19362286+5013034, KIC 11918614 | |
| GSC 03564-00642: 2MASS J19361440+5013096, KIC 11918550 | |
| Database references | |
| SIMBAD | θ Cygni |
| θ Cygni B | |
| θ Cygni C | |
| θ Cygni D | |
| GJ 765B | |
| GSC 03564-00642 | |
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