Editing Boötes (section)

==== Variable stars ====
Two of the brighter Mira-type variable stars in the constellation are [[R Boötis|R]] and [[S Boötis]]. Both are red giants that range greatly in magnitude—from 6.2 to 13.1 over 223.4 days,{{sfn|Pasachoff|2000|pp=199–200}}{{sfn|Moore|2000|pp=341–342}} and 7.8 to 13.8 over a period of 270.7 days, respectively.{{sfn|Moore|2000|pp=341–342}} Also red giants, [[V Boötis|V]] and [[W Boötis]] are [[semi-regular variable star]]s that range in magnitude from 7.0 to 12.0 over a period of 258 days, and magnitude 4.7 to 5.4 over 450 days, respectively.{{sfn|Moore|2000|pp=341–342}}

[[BL Boötis]] is the prototype of its class of pulsating variable stars,{{sfn|North|2004|p=123}} the [[anomalous Cepheids]]. These stars are somewhat similar to [[Cepheid variable]]s, but they do not have the same relationship between their period and luminosity.{{sfn|Good|2003|p=61}} Their periods are similar to [[RRAB variable]]s; however, they are far brighter than these stars.{{sfn|Good|2003|p=69}} BL Boötis is a member of the cluster [[NGC 5466]]. Anomalous Cepheids are [[metallicity|metal poor]] and have masses not much larger than the Sun's, on average, {{Solar mass|1.5|link=y}}. BL Boötis type stars are a subtype of [[RR Lyrae]] variables.{{sfn|Good|2003|p=70}}

[[T Boötis]] was a [[nova]] observed in April 1860 at a magnitude of 9.7. It has never been observed since, but that does not preclude the possibility of it being a highly irregular [[variable star]] or a [[recurrent nova]].{{sfn|Moore|Tirion|1997|pp=132–133}}