▁a ▁neut ron ▁star ▁or ▁a ▁black ▁hole . ▁The ▁other ▁component ▁is ▁an ▁intermediate ▁mass ▁star . ▁ ▁Her cules ▁X - 1 ▁is ▁composed ▁of ▁a ▁neut ron ▁star ▁acc re ting ▁matter ▁from ▁a ▁normal ▁star ▁( H Z ▁Her cul is ) ▁probably ▁due ▁to ▁Ro che ▁lo be ▁overflow . ▁X - 1 ▁is ▁the ▁prototype ▁for ▁the ▁massive ▁X - ray ▁bin aries ▁although ▁it ▁falls ▁on ▁the ▁border line , ▁, ▁between ▁high - ▁and ▁low - mass ▁X - ray ▁bin aries . ▁ ▁Cel est ial ▁X - ray ▁sources ▁ ▁The ▁cel est ial ▁sphere ▁has ▁been ▁divided ▁into ▁ 8 8 ▁const ell ations . ▁The ▁International ▁Astronom ical ▁Union ▁( IA U ) ▁const ell ations ▁are ▁areas ▁of ▁the ▁sky . ▁Each ▁of ▁these ▁contains ▁remarkable ▁X - ray ▁sources . ▁Some ▁of ▁them ▁have ▁been ▁identified ▁from ▁ast ro phys ical ▁model ing ▁to ▁be ▁galaxies ▁or ▁black ▁holes ▁at ▁the ▁cent ers ▁of ▁galaxies . ▁Some ▁are ▁p uls ars . ▁As ▁with ▁sources ▁already ▁successfully ▁mode led ▁by ▁X - ray ▁ast ro physics , ▁st riv ing ▁to ▁understand ▁the ▁generation ▁of ▁X - ray s ▁by ▁the ▁apparent ▁source ▁helps ▁to ▁understand ▁the ▁Sun , ▁the ▁universe ▁as ▁a ▁whole , ▁and ▁how ▁these ▁affect ▁us ▁on ▁Earth . ▁Const ell ations ▁are ▁an ▁astronom ical ▁device ▁for ▁handling ▁observation ▁and ▁precision ▁independent ▁of ▁current ▁physical ▁theory ▁or ▁interpretation . ▁Astronom y ▁has ▁been ▁around