Lambda Cygni

Lambda Cygni
Location of λ Cygni (circled in red)
Observation data
Epoch J2000      Equinox ICRS
Constellation Cygnus
Right ascension 20h 47m 24.53766s
Declination +36° 29′ 26.5737″
Apparent magnitude (V) 4.54
Characteristics
Spectral type B5Ve
U−B color index −0.50
B−V color index −0.11
Variable type Be star
Astrometry
Radial velocity (Rv)-23.20 km/s
Proper motion (μ) RA: +14.71< mas/yr
Dec.: −8.96 mas/yr
Parallax (π)4.24±0.43 mas
Distanceapprox. 770 ly
(approx. 240 pc)
Details
λ Cyg Aa
Mass6.40 M☉
Radius3.56 R☉
Surface gravity (log g)3.195 cgs
Temperature13,925 K
Rotational velocity (v sin i)133 km/s
λ Cyg Ab
Mass6.40 M☉
λ Cyg B
Mass5.12 M☉
Other designations
54 Cygni, GC 28994, HD 198183, HIP 102589, HR 7963, SAO 70505, CCDM J20475+3629, WDS J20474+3629
Database references
SIMBADdata

Lambda Cygni is a multiple star system in the northern constellation of Cygnus. Its name is a Bayer designation that is Latinized from λ Cygni and abbreviated λ Cyg or λ Cyg. With an apparent visual magnitude of 4.54, it is visible to the naked eye as a point of light. The system is located at a distance of approximately 770 light years based on parallax measurements.

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. Component B has type B7V, magnitude 6.26, and separation 0.77" (about 180 AU based on parallax). Component C has reported type K2III-IV, apparent magnitude 9.65, and separation about 85". 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.

References

  1. 1 2 3 4 5 6 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
  2. 1 2 3 4 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.
  3. ↑ 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.
  4. ↑ 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.
  5. ↑ 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.
  6. 1 2 3 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.
  7. ↑ Pasinetti Fracassini, L. E.; et al. (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
  8. 1 2 3 Frémat, Y.; et al. (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.
  9. 1 2 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
  10. ↑ 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
  11. 1 2 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