}}{{Starbox reference
| Simbad=59+Cyg
}}{{Starbox end}}59 Cygni is a multiple[13] star system in the northern constellation of Cygnus, located roughly 1,300 light years away from Earth. It is visible to the naked eye as a blue-white hued star with a combined apparent visual magnitude of 4.74.[3]The primary component and brightest member of this system, designated 59 Cyg Aa, is a rapidly rotating Be star with a stellar classification of B1.5 Vnne.[4] This is a well-studied star thanks to pronounced spectral variations that have been observed since 1916, and two short-term shell star phases that were observed in 1973 and 1974–5.[19] It is actually a confirmed spectroscopic binary system with a high temperature subdwarf O-type companion in a 28-day orbital period. The latter is heating the nearest side of the circumstellar gaseous disk that surrounds the primary.[13]
Orbiting the primary pair is 59 Cyg Ab, a magnitude 7.64 A-type main-sequence star of class A3V, located at an angular separation of {{Val|0.200|u=arcsecond}}. A fourth component is a magnitude 9.8 A-type giant star of class A8III at a separation of {{val|20.2|u=arcsecond}} along a position angle (PA) of 352°, as of 2008. The fifth companion is magnitude 11.7 at a separation of {{Val|26.7|u=arcsecond}} and a PA of 141°.[5] Gaia Data Release 2 suggests that the companions at {{val|20.2|u=arcsecond}} and {{Val|26.7|u=arcsecond}} are respectively {{val|382|ul=pc}} and {{val|366|u=pc}} away and moving in approximately the same direction as the primary triple.[22][23]
References
1. ^1 2 3 4 5 {{Cite Gaia DR2}}
2. ^1 {{cite DR2|2163949423055031424}}
3. ^1 {{cite DR2|2163946429452212480}}
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5. ^1 2 3 4 5 {{citation | title=XHIP: An extended hipparcos compilation | last1=Anderson | first1=E. | last2=Francis | first2=Ch. | journal=Astronomy Letters | volume=38 | issue=5 | pages=331 | year=2012 | bibcode=2012AstL...38..331A | doi=10.1134/S1063773712050015 | arxiv=1108.4971 | postscript=. }}
6. ^1 {{citation | title=Properties and nature of Be stars. XXI. The long-term and the orbital variations of V832 Cyg = 59 Cyg | last1=Harmanec | first1=P. | last2=Bozić | first2=H. | last3=Percy | first3=J. R. | last4=Yang | first4=S. | last5=Ruzdjak | first5=D. | last6=Sudar | first6=D. | last7=Wolf | first7=M. | last8=Iliev | first8=L. | last9=Huang | first9=L. | last10=Buil | first10=C. | last11=Eenens | first11=P. | display-authors=1 | journal=Astronomy and Astrophysics | postscript=. | volume=387 | pages=580–594 | date=May 2002 | doi=10.1051/0004-6361:20020453 | bibcode=2002A&A...387..580H }}
7. ^1 2 {{citation | title=A catalogue of multiplicity among bright stellar systems | last1=Eggleton | first1=P. P. | last2=Tokovinin | first2=A. A. | journal=Monthly Notices of the Royal Astronomical Society | volume=389 | issue=2 | pages=869 | date=2008 | doi=10.1111/j.1365-2966.2008.13596.x | postscript=. | bibcode=2008MNRAS.389..869E | arxiv=0806.2878 }}
8. ^1 2 {{citation | last=Lesh | first=Janet Rountree | postscript=. | title=The Kinematics of the Gould Belt: an Expanding Group? | journal=Astrophysical Journal Supplement | volume=17 | page=371 | date=December 1968 | doi=10.1086/190179 | bibcode=1968ApJS...17..371L }}
9. ^1 2 3 4 {{citation | title=Far-ultraviolet Detection of the Suspected Subdwarf Companion to the Be Star 59 Cygni | display-authors=1 | last1=Peters | first1=Geraldine J. | last2=Pewett | first2=Tiffany D. | last3=Gies | first3=Douglas R. | last4=Touhami | first4=Yamina N. | last5=Grundstrom | first5=Erika D. | journal=The Astrophysical Journal | volume=765 | issue=1 | id=2 | pages=8 | date=March 2013 | doi=10.1088/0004-637X/765/1/2 | bibcode=2013ApJ...765....2P | arxiv=1301.0257 | postscript=. }}