Xi Cygni
ξ Cygni (Latinised as Xi Cygni) is a spectroscopic binary star in the constellation Cygnus. Its apparent magnitude is 3.73 and it is located around 360 parsecs (1,200 ly) away.
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Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Cygnus |
Right ascension | 21h 04m 55.874s[1] |
Declination | +43° 55′ 40.285″[1] |
Apparent magnitude (V) | 3.73[2] |
Characteristics | |
Spectral type | K4:Ib- + A1.5V[3] |
U−B color index | +1.78[2] |
B−V color index | +1.66[2] |
Astrometry | |
Radial velocity (Rv) | -19.10[4] km/s |
Proper motion (μ) | RA: +9.763[5] mas/yr Dec.: +0.646[5] mas/yr |
Parallax (π) | 3.59 ± 0.45[5] mas |
Distance | approx. 900 ly (approx. 280 pc) |
Absolute magnitude (MV) | −4.3/+1.3[3] |
Orbit[6] | |
Period (P) | 6,750 ± 200 days |
Semi-major axis (a) | ~766 R☉ |
Eccentricity (e) | 0.25 ± 0.07 |
Inclination (i) | ~50° |
Details | |
Primary | |
Mass | ~8[6] M☉ |
Radius | 174[1] R☉ |
Luminosity | 6,081 - 6,368[1] L☉ |
Surface gravity (log g) | 1.00[7] cgs |
Temperature | 3,898±170[1] K |
Metallicity [Fe/H] | −0.41[7] dex |
Secondary | |
Mass | ~2.5[6] M☉ |
Other designations | |
Database references | |
SIMBAD | data |
The system contains two stars which orbit every 18 years in a mildly eccentric orbit. The primary star is a supergiant with a spectral type of around K4, while the secondary is an A-type main-sequence star with a spectral type of A1.5. Stellar winds from the supergiant have been measured at around 50 km/s, but with variations in speed and individual line strengths.[6]
ξ Cygni is in the Kepler spacecraft's field of view but no planets have been detected.[8]
- H-alpha RGB amateur image of ξ Cygni, center star, at edge of NGC7000
- NGC 7000 (North America Nebula). ξ Cygni is the bright star on the left.
References
- Messineo, M.; Brown, A. G. A. (2019). "A Catalog of Known Galactic K-M Stars of Class I Candidate Red Supergiants in Gaia DR2". The Astronomical Journal. 158 (1): 20. arXiv:1905.03744. Bibcode:2019AJ....158...20M. doi:10.3847/1538-3881/ab1cbd. S2CID 148571616.
- Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues. 2237: 0. Bibcode:2002yCat.2237....0D.
- Ginestet, N.; Carquillat, J. M. (2002). "Spectral Classification of the Hot Components of a Large Sample of Stars with Composite Spectra, and Implication for the Absolute Magnitudes of the Cool Supergiant Components". The Astrophysical Journal Supplement Series. 143 (2): 513. Bibcode:2002ApJS..143..513G. doi:10.1086/342942.
- Famaey, B.; et al. (January 2005), "Local kinematics of K and M giants from CORAVEL/Hipparcos/Tycho-2 data. Revisiting the concept of superclusters", Astronomy and Astrophysics, 430 (1): 165–186, arXiv:astro-ph/0409579, Bibcode:2005A&A...430..165F, doi:10.1051/0004-6361:20041272, S2CID 17804304
- Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
- Reimers, D.; Schroeder, K.-P. (1989). "Observations of modulation and phase displacement of the stellar wind in six red giant spectroscopic binaries". Astronomy and Astrophysics. 214: 261. Bibcode:1989A&A...214..261R.
- Hekker, S.; Meléndez, J. (2007). "Precise radial velocities of giant stars. III. Spectroscopic stellar parameters". Astronomy and Astrophysics. 475 (3): 1003. arXiv:0709.1145. Bibcode:2007A&A...475.1003H. doi:10.1051/0004-6361:20078233. S2CID 10436552.
- Molenda-Żakowicz, J.; Sousa, S. G.; Frasca, A.; Uytterhoeven, K.; Briquet, M.; Van Winckel, H.; Drobek, D.; Niemczura, E.; Lampens, P.; Lykke, J.; Bloemen, S.; Gameiro, J. F.; Jean, C.; Volpi, D.; Gorlova, N.; Mortier, A.; Tsantaki, M.; Raskin, G. (2013). "Atmospheric parameters of 169 F-, G-, K- and M-type stars in the Kepler field". Monthly Notices of the Royal Astronomical Society. 434 (2): 1422. arXiv:1306.6011. Bibcode:2013MNRAS.434.1422M. doi:10.1093/mnras/stt1095. S2CID 59269553.
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