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Lambda Cygni 
Summary
Lambda Cygni (λ Cyg) is a class B5V (blue main-sequence) star in the constellation Cygnus. Its apparent magnitude is 4.54[2] and it is approximately 770 light years away based on parallax.[1]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Cygnus |
| Right ascension | 20h 47m 24.53766s[1] |
| Declination | 36° 29′ 26.5737″[1] |
| Apparent magnitude (V) | 4.54[2] |
| Characteristics | |
| Spectral type | B5Ve[3] |
| U−B color index | -0.50 [2] |
| B−V color index | -0.11 [2] |
| Variable type | Be star[4] |
| Astrometry | |
| Radial velocity (Rv) | -23.20[5] km/s |
| Proper motion (μ) | RA: +14.71[1] mas/yr Dec.: -8.96[1] mas/yr |
| Parallax (π) | 4.24 ± 0.43 mas[1] |
| Distance | approx. 770 ly (approx. 240 pc) |
| Details | |
| λ Cyg Aa | |
| Mass | 6.40[6] M☉ |
| Radius | 3.56[7] R☉ |
| Surface gravity (log g) | 3.195[8] cgs |
| Temperature | 13,925[8] K |
| Rotational velocity (v sin i) | 133[8] km/s |
| λ Cyg Ab | |
| Mass | 6.40[6] M☉ |
| λ Cyg B | |
| Mass | 5.12[6] M☉ |
| Other designations | |
| Database references | |
| SIMBAD | data |
Lambda Cygni is a multiple star, with components A, B, and C observed in the 19th century; the main component, A, is a spectroscopic binary itself with two components Aa and Ab reported at magnitudes 5.4 and 5.8 orbiting with a period of 12 years.[9] Component B has type B7V, magnitude 6.26, and separation 0.77" (about 180 AU based on parallax).[9][10] Component C has reported type K2III-IV, apparent magnitude 9.65, and separation about 85".[11] Recent observations indicate the presence of additional smaller companions D (about 50" from A), E (about 8" from C), and F (about 40" from C) all around apparent magnitude 14.[11]
References edit
- ^ a b c d e f van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. S2CID 18759600. Vizier catalog entry
- ^ a b c d 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.
- ^ Yudin, R. V. (2001). "Statistical analysis of intrinsic polarization, IR excess and projected rotational velocity distributions of classical Be stars". Astronomy and Astrophysics. 368 (3): 912–931. Bibcode:2001A&A...368..912Y. doi:10.1051/0004-6361:20000577.
- ^ 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. Bibcode:2009yCat....102025S.
- ^ Kharchenko, N. V.; et al. (2007), "Astrophysical supplements to the ASCC-2.5: Ia. Radial velocities of ˜55000 stars and mean radial velocities of 516 Galactic open clusters and associations", Astronomische Nachrichten, 328 (9): 889, arXiv:0705.0878, Bibcode:2007AN....328..889K, doi:10.1002/asna.200710776, S2CID 119323941
- ^ a b c Tokovinin, A. (2008). "Comparative statistics and origin of triple and quadruple stars". Monthly Notices of the Royal Astronomical Society. 389 (2): 925–938. arXiv:0806.3263. Bibcode:2008MNRAS.389..925T. doi:10.1111/j.1365-2966.2008.13613.x. S2CID 16452670.
- ^ Pasinetti Fracassini, L. E.; Pastori, L.; Covino, S.; Pozzi, A. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS) - Third edition", Astronomy and Astrophysics, 367 (2): 521–524, arXiv:astro-ph/0012289, Bibcode:2001A&A...367..521P, doi:10.1051/0004-6361:20000451, S2CID 425754 Vizier catalog entry
- ^ a b c Frémat, Y.; Zorec, J.; Hubert, A.-M.; Floquet, M. (2005). "Effects of gravitational darkening on the determination of fundamental parameters in fast-rotating B-type stars". Astronomy and Astrophysics. 440 (1): 305. arXiv:astro-ph/0503381. Bibcode:2005A&A...440..305F. doi:10.1051/0004-6361:20042229. S2CID 19016751.
- ^ a b Malkov, O. Yu.; et al. (October 2012), "Dynamical masses of a selected sample of orbital binaries", Astronomy & Astrophysics, 546 (A69): A69, Bibcode:2012A&A...546A..69M, doi:10.1051/0004-6361/201219774 Vizier catalog entry
- ^ Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976 Vizier catalog entry
- ^ a b Mason, Brian D.; et al. (December 2001), "The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog", The Astronomical Journal, 122 (6): 3466–3471, Bibcode:2001AJ....122.3466M, doi:10.1086/323920 Vizier catalog entry