 its count its time. and almarzam was mentioned with alshira and they are the two stars of the arm. and perhaps they did the same with the two arms so they attributed the star to them because the two names are the same and the meanings are close and the star is for the one taken from them. dhu alrummah said
عدانها ، وقتها. وذكر المرزم مع الشعرى، وهما كوكبا الذراع. وربما فعلوا مثل هذا فى الذراعين، فنسبوا النوء إليهما، لاتفاق الاسمين وتقارب المعنيين، وإنما النوء للمقبوضة منهما. قال ذو الرمة