33 Cygni
Single star in the constellation Cygnus
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33 Cygni is a single[7] star located 159 light years away in the northern constellation Cygnus. It is visible to the naked eye as a white-hued star with an apparent visual magnitude of 4.28.[2] The star is moving closer to the Earth with a heliocentric radial velocity of −16 km/s.[5] Eggen (1995) listed it as a proper motion candidate for membership in the IC 2391 supercluster.[9]
 | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Cygnus |
| Right ascension | 20h 13m 23.86661s[1] |
| Declination | +56° 34′ 03.7999″[1] |
| Apparent magnitude (V) | 4.28[2] |
| Characteristics | |
| Evolutionary stage | main sequence[3] |
| Spectral type | A3 IV–Vn[4] |
| B−V color index | 0.114±0.001[2] |
| Astrometry | |
| Radial velocity (Rv) | −16.13±2.53[5] km/s |
| Proper motion (μ) | RA: +61.82[1] mas/yr Dec.: +82.18[1] mas/yr |
| Parallax (π) | 20.48±0.12 mas[1] |
| Distance | 159.3 ± 0.9 ly (48.8 ± 0.3 pc) |
| Absolute magnitude (MV) | 0.84[2] |
| Details[3] | |
| Mass | 2.33±0.01 M☉ |
| Radius | 2.76[6] R☉ |
| Luminosity | 44.3±1.0 L☉ |
| Temperature | 8,395+97 −96 K |
| Rotational velocity (v sin i) | 243 km/s |
| Age | 400[7] Myr |
| Other designations | |
| 33 Cyg, BD+56°2376, FK5 758, HD 192696, HIP 99655, HR 7740, SAO 32378, WDS J20145+3648A[8] | |
| Database references | |
| SIMBAD | data |
This star has a stellar classification of A3 IV–Vn,[4] showing a spectrum with traits intermediate between an A-type main-sequence star and an evolving subgiant star. The 'n' suffix indicates "nebulous" absorption lines due to rapid rotation. It is about 400[7] million years old with a high projected rotational velocity of 243 km/s.[3] This rate of spin is giving the star an oblate shape with a pronounced equatorial bulge that is an estimated 28% wider than the polar radius.[10]
33 Cyg has 2.33[3] times the mass of the Sun and 2.76[6] times the Sun's radius. The star is radiating 44 times the Sun's luminosity from its photosphere at an effective temperature of 8,395 K.[3] It displays an infrared excess that suggests an orbiting debris disk with a temperature of 500 K at a mean distance of 1.80 AU from the host star.[6]