Editing Deneb (section)

===Possible spectroscopic companion===
Deneb has been reported as a possible single line spectroscopic [[Binary star|binary]] with a period of about 850 days, where the spectral lines from the star suggest cyclical radial velocity changes.<ref name="Lucy1976">{{cite journal|bibcode=1976ApJ...206..499L|title=An analysis of the variable radial velocity of alpha Cygni|journal=Astrophysical Journal|volume=206|pages=499|last1=Lucy|first1=L. B.|year=1976|doi=10.1086/154405|doi-access=free}}</ref> Later investigations have found no evidence supporting the existence of a companion.<ref name="Richardson2011">{{cite journal |bibcode=2011AJ....141...17R |title=A Five-year Spectroscopic and Photometric Campaign on the Prototypical α Cygni Variable and A-type Supergiant Star Deneb |journal=The Astronomical Journal |volume=141 |issue=1 |pages=17 |last1=Richardson |first1=N. D. |last2=Morrison |first2=N. D. |last3=Kryukova |first3=E. E. |last4=Adelman |first4=S. J. |year=2011 |doi=10.1088/0004-6256/141/1/17 |arxiv=1009.5994 |s2cid=118300333}}</ref>