30 Cygni
Star in the constellation Cygnus
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30 Cygni (ο1 Cygni) is a class A5III (white giant) star in the constellation Cygnus. Its apparent magnitude is 4.83 and it is approximately 610 light years away based on parallax.
 | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Cygnus[1] |
| Right ascension | 20h 13m 18.05358s[2] |
| Declination | +46° 48′ 56.4424″[2] |
| Apparent magnitude (V) | 4.83[3] (4.81 - 4.84[4]) |
| Characteristics | |
| Spectral type | A5IIIn[5] |
| U−B color index | +0.17[3] |
| B−V color index | +0.10[3] |
| Variable type | suspected[4] |
| Astrometry | |
| Radial velocity (Rv) | −26.00[6] km/s |
| Proper motion (μ) | RA: +13.83[2] mas/yr Dec.: +3.00[2] mas/yr |
| Parallax (π) | 5.34±0.33 mas[2] |
| Distance | 610 ± 40 ly (190 ± 10 pc) |
| Absolute magnitude (MV) | −1.55[1] |
| Details | |
| Mass | 2.1[7] M☉ |
| Radius | 9.91[8] R☉ |
| Luminosity | 310[8] L☉ |
| Surface gravity (log g) | 3.61[7] cgs |
| Temperature | 7,893[7] K |
| Metallicity [Fe/H] | −0.55[7] dex |
| Rotational velocity (v sin i) | 145[9] km/s |
| Other designations | |
| ο1 Cygni,[10] BD+46°2881, GC 28091, HIP 99639, HR 7730, HD 192514, SAO 49332, WDS J20136+4644D, CCDM J20135+4646D | |
| Database references | |
| SIMBAD | data |
The Bayer letter ο (omicron) has been variously applied to two or three of the stars 30, 31, and 32 Cygni. 30 Cygni has sometimes been designated as ο1 Cygni with the other two stars being ο2 and ο3 respectively. For clarity, it is preferred to use the Flamsteed designation 30 Cygni rather than one of the Bayer designations.[10]
30 Cygni is about six arc-minutes from 31 Cygni A and seven arc-minutes from 31 Cygni B. That pair is known as ο1 Cygni, while ο2 Cygni is a degree away. Both ο1 and ο2 are 4th magnitude stars.