▁hydro gen ▁layers ▁after ▁it ▁expanded ▁away ▁from ▁the ▁main ▁sequence . ▁ ▁It ▁is ▁thought ▁to ▁have ▁origin ated ▁as ▁a ▁main ▁sequence ▁star ▁with ▁around ▁, ▁expanded ▁when ▁it ▁exha usted ▁its ▁core ▁hydro gen , ▁and ▁now ▁only ▁ ▁remains , ▁highly ▁infl ated ▁and ▁giving ▁the ▁appearance ▁of ▁a ▁super gi ant ▁star . ▁ ▁Other ▁estimates ▁give ▁higher ▁masses , ▁as ▁much ▁as ▁ ▁and ▁ ▁at ▁the ▁known ▁incl ination ▁of ▁ 5 0 ° . ▁▁ υ ▁S gr 1 ▁is ▁also ▁class ified ▁as ▁an ▁P V ▁T eles cop ii ▁variable , ▁although ▁it ▁was ▁originally ▁catalog ued ▁as ▁an ▁e cli ps ing ▁binary . ▁ ▁It ▁shows ▁apparent ▁magnitude ▁fl uct u ations ▁between ▁+ 4 . 5 1 ▁and ▁+ 4 . 6 5 ▁with ▁a ▁period ▁of ▁approximately ▁ 2 0 ▁days . ▁ ▁The ▁companion , ▁ υ ▁S gr 2 , ▁is ▁more ▁massive ▁than ▁the ▁super gi ant ▁primary , ▁but ▁so ▁dim ▁at ▁visible ▁frequencies ▁as ▁to ▁be ▁und et ect able . ▁ ▁It ▁is ▁thought ▁to ▁be ▁a ▁B - type ▁main ▁sequence ▁star ▁acc re ting ▁mass ▁from ▁the ▁primary . ▁ ▁N aming ▁ υ ▁S ag itt ari i ▁has ▁two ▁entries ▁in ▁the ▁Henry ▁Dra per ▁Catalogue , ▁HD ▁ 1 8 1 6 1 5 ▁and ▁HD ▁ 1 8 1 6 1 6 . ▁ ▁In ▁Chinese , ▁ ▁( ), ▁meaning ▁Est ab lish ment , ▁refers