Lambda Cygni

{{short description|Star in the constellation Cygnus}}

{{Starbox begin

| name = Lambda Cygni

}}

{{Starbox observe

| epoch = J2000

| constell = Cygnus

| ra = {{RA|20|47|24.53766}}{{cite journal | title=Validation of the new Hipparcos reduction | url=http://www.aanda.org/articles/aa/full/2007/41/aa8357-07/aa8357-07.html | last1=van Leeuwen | first1=F. | journal=Astronomy and Astrophysics | volume=474 | issue=2 | pages=653–664 | date=2007 | arxiv=0708.1752 | bibcode=2007A&A...474..653V | doi=10.1051/0004-6361:20078357 | s2cid=18759600 }} [http://vizier.u-strasbg.fr/viz-bin/VizieR-S?HIP%20102589 Vizier catalog entry]

| dec = {{DEC|+36|29|26.5737}}

| appmag_v = 4.54{{cite journal |bibcode=2002yCat.2237....0D |title=VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system |journal=CDS/ADC Collection of Electronic Catalogues |volume=2237 |pages=0 |last1=Ducati |first1=J. R. |date=2002}}

}}

{{Starbox character

| class = B5Ve{{cite journal|bibcode= 2001A&A...368..912Y|title= Statistical analysis of intrinsic polarization, IR excess and projected rotational velocity distributions of classical Be stars|journal= Astronomy and Astrophysics|volume= 368|issue= 3|pages= 912–931|last1= Yudin|first1= R. V.|year= 2001|doi= 10.1051/0004-6361:20000577|doi-access= free}}

| b-v = −0.11

| u-b = −0.50

| variable = Be star{{cite journal|bibcode=2009yCat....102025S|title=VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)|journal=VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S|volume=1|display-authors=etal|last1=Samus|first1=N. N.|last2=Durlevich|first2=O. V.|year=2009}}

}}

{{Starbox astrometry

| radial_v = -23.20{{citation | display-authors=1 | last1=Kharchenko | first1=N. V. | last2=Scholz | first2=R.-D. | last3=Piskunov | first3=A. E. | last4=Röser | first4=S. | last5=Schilbach | first5=E. | bibcode=2007AN....328..889K | title=Astrophysical supplements to the ASCC-2.5: Ia. Radial velocities of ˜55000 stars and mean radial velocities of 516 Galactic open clusters and associations | journal=Astronomische Nachrichten | volume=328 | issue=9 | pages=889 | year=2007 | doi=10.1002/asna.200710776|arxiv = 0705.0878 | s2cid=119323941 }}

| prop_mo_ra = +14.71

| prop_mo_dec = −8.96

| parallax = 4.24

| p_error = 0.43

| parallax_footnote =

| absmag_v =

}}

{{Starbox detail

| component1 = λ Cyg Aa

| mass = 6.40{{cite journal|bibcode= 2008MNRAS.389..925T|title= Comparative statistics and origin of triple and quadruple stars|journal= Monthly Notices of the Royal Astronomical Society|volume= 389|issue= 2|pages= 925–938|last1= Tokovinin|first1= A.|year= 2008|doi= 10.1111/j.1365-2966.2008.13613.x|doi-access= free|arxiv = 0806.3263 |s2cid= 16452670}}

| temperature = 13,925{{cite journal|bibcode= 2005A&A...440..305F|title= Effects of gravitational darkening on the determination of fundamental parameters in fast-rotating B-type stars|journal= Astronomy and Astrophysics|volume= 440|pages= 305|last1= Frémat|first1= Y.|last2= Zorec|first2= J.|last3= Hubert|first3= A.-M.|last4= Floquet|first4= M.|year= 2005|issue= 1|doi= 10.1051/0004-6361:20042229|arxiv = astro-ph/0503381 |s2cid= 19016751}}

| gravity = 3.195

| rotational_velocity = 133

| radius = 3.56{{citation | last1=Pasinetti Fracassini | first1=L. E. | last2=Pastori | first2=L. | last3=Covino | first3=S. | last4=Pozzi | first4=A. | title=Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS) - Third edition | journal=Astronomy and Astrophysics | volume=367 | issue=2 | pages=521–524 |date=February 2001 | bibcode=2001A&A...367..521P | doi=10.1051/0004-6361:20000451 | arxiv=astro-ph/0012289 | s2cid=425754 }} [http://webviz.u-strasbg.fr/viz-bin/VizieR-5?-ref=VIZ57076b959023&-out.add=.&-source=II/224/cadars&recno=9691 Vizier catalog entry]

| component2 = λ Cyg Ab

| mass2 = 6.40

}}

{{Starbox detail|no_heading=y

| component1 = λ Cyg B

| mass = 5.12

}}

{{Starbox catalog

| names = 54 Cygni, CCDM J20475+3629, GC 28994, HIP 102589, HR 7963, HD 198183, SAO 70505, WDS J20474+3629

}}

{{Starbox reference

| Simbad = Lambda+Cygni

}}

{{Starbox end}}

Lambda Cygni (λ Cyg) is a class B5V (blue main-sequence) star in the constellation Cygnus. Its apparent magnitude is 4.54 and it is approximately 770 light years away based on parallax.

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.{{citation | display-authors=1 | last1=Malkov | first1=O. Yu. | last2=Tamazian | first2=V. S. | last3=Docobo | first3=J. A. | last4=Chulkov | first4=D. A. | title=Dynamical masses of a selected sample of orbital binaries | journal=Astronomy & Astrophysics | volume=546 | issue=A69 | pages=A69 | date=October 2012 | bibcode=2012A&A...546A..69M | doi=10.1051/0004-6361/201219774 | doi-access=free }} [http://vizier.u-strasbg.fr/viz-bin/VizieR-4?-source=J/A%2bA/546/A69/table1&WDS=20474%2B3629 Vizier catalog entry] Component B has type B7V, magnitude 6.26, and separation 0.77" (about 180 AU based on parallax).{{citation | last1=Eggleton | first1=P. P. | last2=Tokovinin | first2=A. A. | title=A catalogue of multiplicity among bright stellar systems | journal=Monthly Notices of the Royal Astronomical Society | volume=389 | issue=2 | pages=869–879 | date=September 2008 | bibcode=2008MNRAS.389..869E | doi=10.1111/j.1365-2966.2008.13596.x | doi-access=free | arxiv = 0806.2878 | s2cid=14878976 }} [http://vizier.u-strasbg.fr/viz-bin/VizieR-4?-source=J/MNRAS/389/869/table1&mHR=7963 Vizier catalog entry] Component C has reported type K2III-IV, apparent magnitude 9.65, and separation about 85".{{citation | display-authors=1 | last1=Mason | first1=Brian D. | last2=Wycoff | first2=Gary L. | last3=Hartkopf | first3=William I. | last4=Douglass | first4=Geoffrey G. | last5=Worley | first5=Charles E. | title=The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog | journal=The Astronomical Journal | volume=122 | issue=6 | pages=3466–3471 | date=December 2001 | bibcode=2001AJ....122.3466M | doi=10.1086/323920 | doi-access=free }} [http://vizier.u-strasbg.fr/viz-bin/VizieR-4?-source=B/wds/wds&WDS=20474%2B3629 Vizier catalog entry] 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.