59 Cygni
Star in the constellation Cygnus
From Wikipedia, the free encyclopedia
59 Cygni is a multiple[6] star system in the northern constellation of Cygnus, located roughly 1,300 light years away from Earth. It is visible to the naked eye as a blue-white hued star with a combined apparent visual magnitude of 4.74.[2]
  | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Cygnus |
| Right ascension | 20h 59m 49.55164s[1] |
| Declination | +47° 31′ 15.3789″[1] |
| Apparent magnitude (V) | 4.74[2] |
| Characteristics | |
| Spectral type | B1.5Vnne[3] + sdO + A3V + A8III + ?[4] |
| B−V color index | −0.084±0.004[2] |
| Variable type | γ Cas[5] |
| Astrometry | |
| Radial velocity (Rv) | 1.4±4.2[2] km/s |
| Proper motion (μ) | RA: +9.534[1] mas/yr Dec.: +3.090[1] mas/yr |
| Parallax (π) | 2.5088±0.3226 mas[1] |
| Distance | approx. 1,300 ly (approx. 400 pc) |
| Absolute magnitude (MV) | −3.37[2] |
| Orbit[6] | |
| Period (P) | 28.1871±0.0011 d |
| Eccentricity (e) | 0.141±0.008 |
| Periastron epoch (T) | 45677.6±0.3 HJD |
| Argument of periastron (ω) (secondary) | 257±4° |
| Semi-amplitude (K1) (primary) | 11.7±0.9 km/s |
| Semi-amplitude (K2) (secondary) | 121.3±1.1 km/s |
| Details[6] | |
| 59 Cyg Aa – Be star | |
| Mass | 6.3–9.4 M☉ |
| Radius | 5.5–7.0 R☉ |
| Luminosity | 7,943 L☉ |
| Surface gravity (log g) | 3.78±0.09 cgs |
| Temperature | 21,800±700 K |
| Rotational velocity (v sin i) | 379±27 km/s |
| 59 Cyg Aa – sdO | |
| Mass | 0.62–0.91 M☉ |
| Radius | 0.34–0.43 R☉ |
| Luminosity | 1,000 L☉ |
| Surface gravity (log g) | 5.0±1.0 cgs |
| Temperature | 52,100±4,800 K |
| Rotational velocity (v sin i) | < 40 km/s |
| Other designations | |
| f1 Cyg, 59 Cyg, V832 Cyg, BD+46°3133, FK5 1551, HD 200120, HIP 103632, HR 8047, SAO 50335, WDS J20598+4731[7] | |
| Database references | |
| SIMBAD | data |
The primary component and brightest member of this system, designated 59 Cyg Aa, is a rapidly rotating Be star with a stellar classification of B1.5 Vnne.[3] This is a well-studied star thanks to pronounced spectral variations that have been observed since 1916, and two short-term shell star phases that were observed in 1973 and 1974–5.[9] It is actually a confirmed spectroscopic binary system with a high temperature subdwarf O-type companion in a 28-day orbital period. The latter is heating the nearest side of the circumstellar gaseous disk that surrounds the primary.[6]
Orbiting the primary pair is 59 Cyg Ab, a magnitude 7.64 A-type main-sequence star of class A3V, located at an angular separation of 0.200″. A fourth component is a magnitude 9.8 A-type giant star of class A8III at a separation of 20.2″ along a position angle (PA) of 352°, as of 2008. The fifth companion is magnitude 11.7 at a separation of 26.7″ and a PA of 141°.[4] Gaia Data Release 2 suggests that the companions at 20.2″ and 26.7″ are respectively 382 pc and 366 pc away and moving in approximately the same direction as the primary triple.[10][11]