| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Cygnus |
| Right ascension | 20h 52m 3.57718s |
| Declination | +34° 39′ 27.4861″ |
| Apparent magnitude (V) | 7.3 - 7.9 |
| Characteristics | |
| Primary | |
| Spectral type | O9.5V |
| Apparent magnitude (U) | 5.91[citation needed] |
| Apparent magnitude (B) | 6.996[citation needed] |
| Apparent magnitude (V) | 7.287 |
| U−B color index | −1.086 |
| B−V color index | −0.291 |
| Secondary | |
| Spectral type | O9.5V |
| Apparent magnitude (U) | 5.883[citation needed] |
| Apparent magnitude (B) | 6.974[citation needed] |
| Apparent magnitude (V) | 7.265 |
| U−B color index | −1.091 |
| B−V color index | −0.291 |
| Variable type | Algol |
| Astrometry | |
| Proper motion (μ) | RA: +2.763 mas/yr Dec.: −15.981 mas/yr |
| Parallax (π) | 0.6759 ± 0.0338 mas |
| Distance | 4,900 ly (1,500 pc) |
| Absolute magnitude (MV) | −3.59/−3.62 |
| Absolute bolometric magnitude (Mbol) | −6.65±0.04/−6.7±0.04 |
| Orbit | |
| Primary | Y Cyg A |
| Companion | Y Cyg B |
| Period (P) | 2.99633210±0.00000031 d |
| Semi-major axis (a) | 28.72 R☉ |
| Eccentricity (e) | 0.14508 |
| Inclination (i) | 86.474±0.019° |
| Periastron epoch (T) | 2,446,308.66407±0.0001 |
| Argument of periastron (ω) (secondary) | 312.514° |
| Argument of periastron (ω) (primary) | 132.514±0.052° |
| Details | |
| Primary | |
| Mass | 17.72±0.35 M☉ |
| Radius | 5.785±0.091 R☉ |
| Luminosity | 36,000 L☉ |
| Surface gravity (log g) | 4.161±0.014 cgs |
| Temperature | 33,200±200 K |
| Rotational velocity (v sin i) | 132 km/s |
| Age | 2 Myr |
| Secondary | |
| Mass | 17.73±0.3 M☉ |
| Radius | 5.816±0.063 R☉ |
| Luminosity | 37,700 L☉ |
| Surface gravity (log g) | 4.157±0.01 cgs |
| Temperature | 33,521±40 K |
| Rotational velocity (v sin i) | 132 km/s |
| Age | 2 Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
Y Cygni is an eclipsing and double-lined spectroscopic binary star system in the constellation of Cygnus. It is located about 4,900 light-years from Earth. The system was one of the first binaries with a convincing detection of the apsidal precession.
The two stars, being O-type main-sequence stars, orbit each other with a period of nearly 3 days.
Observation history
The early type of Y Cyg made it a popular target for astronomers in the past, and spectroscopic orbits have been historically computed numerous times. The first of these studies was published in 1920 by John Stanley Plaskett. Extensive spectroscopic studies of Y Cyg were carried out as early as 1930. Several follow-ups to these have been published in 1959, 1971, and 1980. The latter of these contained an estimate of the period of apsidal precession.
References
- ^ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 8 December 2021.
- ^ a b c d e Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
- ^ a b Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S. 1: B/gcvs. Bibcode:2009yCat....102025S.
- ^ a b c d e f g h i j k l m n o Harmanec, P.; Holmgren, D. E.; Wolf, M.; Božić, H.; Guinan, E. F.; Kang, Y. W.; Mayer, P.; McCook, G. P.; Nemravová, J.; Yang, S.; Šlechta, M.; Ruždjak, D.; Sudar, D.; Svoboda, P. (March 2014). "Revised physical elements of the astrophysically important O9.5+O9.5V eclipsing binary system Y Cygni". Astronomy and Astrophysics. 563: A120. arXiv:1403.0721. Bibcode:2014A&A...563A.120H. doi:10.1051/0004-6361/201323230. ISSN 0004-6361. S2CID 118651473.
- ^ Hill, G.; Holmgren, D. E. (May 1995). "Studies of early-type variable stars. IX. Y Cygni". Astronomy and Astrophysics. 297: 127–134. Bibcode:1995A&A...297..127H.
- ^ Jones, Harold Spencer (1 November 1942). "John Stanley Plaskett, 1865-1941". Obituary Notices of Fellows of the Royal Society. 4 (11): 67–82. doi:10.1098/rsbm.1942.0007.
- ^ Redman, R. O. (August 1930). "Y Cygni". Publications of the Astronomical Society of the Pacific. 42: 250. Bibcode:1930PASP...42..250R. doi:10.1086/124047. S2CID 250785748.
- ^ Struve, O.; Sahade, J.; Zabergs, V. (January 1959). "Y Cygni". Astrophysical Journal. 129: 59. Bibcode:1959ApJ...129...59S. doi:10.1086/146595.
- ^ Vitrichenko, E. A. (1971). "The improvement of the Spectroscopic orbit of Y Cyg". Società Astronomia Italiana. 43: 71. Bibcode:1972MmSAI..43...71V.
- ^ Vitrichenko, E. A. (1971). "The improvement of the Spectroscopic orbit of Y Cyg". Izv. Krym. Astrofiz. Obs. 43: 71–75. Bibcode:1971IzKry..43...71V.
- ^ Gimenez, A.; Costa, V. (December 1980). "Y CYG : photometry and apsidal motion". Publications of the Astronomical Society of the Pacific. 92: 782–784. Bibcode:1980PASP...92..782G. doi:10.1086/130747. S2CID 120757652.