Free Astronomy Magazine September-October 2023 ARABIC VERSION

D HD 45166, the star that might become a magnetar by ESO − Bárbara Ferreira espite having been observed for over 100 years, the enig- matic nature of the star HD 45166 could not be easily explained by conventional models, and little was known about it beyond the fact that it is one of a pair of stars, is rich in helium and is a few times more massive than our Sun. “This star became a bit of an obsession of mine,” says Tomer Shenar, the lead author of a study on this object published in Science and an as- tronomer at the University of Ams- terdam, the Netherlands. “Tomer and I refer to HD 45166 as the ‘zom- bie star’,” says co-author and ESO astronomer Julia Bodensteiner, based in Germany. “This is not only because this star is so unique, but also because I jokingly said that it turns Tomer into a zombie.” Having studied similar helium-rich stars before, Shenar thought mag- netic fields could crack the case. In- deed, magnetic fields are known to influence the behaviour of stars and could explain why traditional mod- els failed to describe HD 45166, which is located about 3000 light- years away in the constellation Mo- noceros. “I remember having a Eureka moment while reading the literature: ‘What if the star is mag- netic?’,” says Shenar, who is cur- rently based at the Centre for Astrobiology in Madrid, Spain. Shenar and his team set out to study the star using multiple facilities around the globe. The main obser- vations were conducted in February ﻣﺠﻠﺔ FreeAstronomy ﺎﻟﻌﺮ ﺔ 46 HD45166" " ﻗﺪ اﻟﻨ ﻢ اﻟﺬ ﺎً ﺼﺒﺢ ﻧ ﻤ ﻣﻐﻨﺎﻃ ﺴ ﺎً : ﻘﻠﻢ ﺎر ﺮا ﻓ ﺮا - اﻟﻤﺮﺻﺪ اﻷوروﺑﻲ اﻟـﺠﻨﻮﺑﻲ إﻧــ اﻟﻨﺠﻢ HD 45166 ﺗﻢ ه رﺻﺪ ﻷﻛﺜﺮ ﻣـﻦ 100 ﻋﺎم إﻻ أﻧﻪ ﻻ ﻳﻤﻜـﻦ ﺗﻔﺴـ اﻟﻄﺒﻴﻌـﺔ اﻟﻐﺎﻣﻀﺔ ﻟﻬﺬا ا ﻟﻨﺠﻢ ﺑ ﺴـﻬﻮﻟﺔ ﻣـﻦ ﺧـﻼل اﻟﻨﻤﺎذج اﻟﺘﻘﻠﻴﺪﻳﺔ وﻟـﻢ ﻳُﻌـﺮف ﻋﻨـﻪ ﺳـﻮى اﻟﻘﻠﻴﻞ ﺑﺨﻼف ﺣﻘﻴﻘﺔ أﻧﻪ أﺣـﺪ ﺛﻨـﺎﺋﻲ ﻣـﻦ اﻟﻨﺠﻮم وﻏﻨﻲ ﺑﺎﻟﻬﻴﻠﻴﻮم و أﻛﱪ ﻋـﺪة ﻣـﺮات اﻟﺸﻤﺲ ﻣﻦ . ﻳﻘـﻮل ﺗـﻮﻣﺮ ﺷـﻴﻨﺎر ا ﺆﻟـﻒ اﻟﺮﺋﻴ ـ ﴘ ﻟﺪراﺳﺔ ﺣﻮل ﻫﺬا اﻟﺠﺴﻢ ا ﻨﺸﻮرة ﰲ ﻣﺠﻠﺔ اﻟﻌﻠﻢ واﻟﻔﻠﻜﻲ ﰲ ﺟﺎﻣﻌﺔ أﻣﺴﱰدام ﺑﻬﻮﻟﻨﺪا " : ﻟﻘﺪ أﺻـﺒﺢ ﻫـﺬا اﻟـﻨﺠﻢ ﻫﺎﺟﺴًـﺎ ﺑﺎﻟﻨﺴـﺒﺔ ﱄ ." ﺗﻘ ـﻮل ﺟﻮﻟﻴ ـﺎ ﺑﻮدﻧﺸـﺘﺎﻳﻨﺮ ا ﺆﻟﻔﺔ ا ﺸـﺎرﻛﺔ وﻋﺎ ـﺔ ا ﻟﻔﻠـﻚ ﰲ ا ﺮﺻـﺪ اﻷوروﺑﻲ اﻟﺠﻨﻮﺑﻲ وﻣﻘﺮﻫـﺎ ﰲ أ ﺎﻧﻴـﺎ أﻧـﺎ " : وﺗﻮﻣﺮ ﻧﺸ إﱃ اﻟﺠﺮم اﻟﺴﻤﺎوي HD 45166 " ﻋﲆ أﻧﻪ اﻟﻨﺠﻢ اﻟﺰوﻣﺒﻲ ﻫﺬا ﻟﻴﺲ ﻓﻘـﻂ ﻷن ﻫﺬا اﻟﻨﺠﻢ ﻓﺮﻳﺪ ﻣﻦ ﻧﻮﻋﻪ وﻟﻜﻦ أﻳﻀًﺎ ﻷﻧﻨـﻲ ﻗﻠﺖ ﻣﺎزﺣًﺎ إﻧﻪ ﻳﺤﻮل ﺗﻮﻣﺮ إﱃ زوﻣﺒﻲ ." ﺑﻌﺪ أن درس ﻧﺠﻮﻣً ﺎ ﻣﻤﺎﺛﻠﺔ ﻏﻨﻴﺔ ﺑﺎﻟﻬﻴﻠﻴﻮم ﻣـﻦ ﻗﺒﻞ اﻋﺘﻘﺪ ﺷﻴﻨﺎر أن ا ﺠﺎﻻت ا ﻐﻨﺎﻃﻴﺴـﻴﺔ ﻳﻤﻜﻦ أن ﺗﺤﻞ ﻫﺬه اﻟﻘﻀﻴﺔ ". ﻣـﻦ ا ﻌـﺮوف - ﺳﺒﺘﻤﺒﺮ ﺃﻛﺘﻮﺑﺮ 2 0 2 3 إن أن ا ﺠﺎﻻت ا ﻐﻨﺎﻃﻴﺴﻴﺔ ﺗـﺆﺛﺮ ﻋـﲆ ﺳـﻠﻮك اﻟﻨﺠﻮم وﻳﻤﻜﻦ أن ﺗﻔﴪﺳﺒﺐ ﻓﺸﻞ اﻟﻨﻤﺎذج اﻟﺘﻘﻠﻴﺪﻳﺔ ﰲ وﺻﻒ HD 45166 اﻟـﺬي ﻳﻘـﻊ ﻋﲆ ﺑﻌﺪ ﺣﻮاﱄ 3000 ﺳﻨﺔ ﺿﻮﺋﻴﺔ ﰲ ﻛﻮﻛﺒﺔ وﺣﻴﺪ اﻟﻘﺮن . ﻳﻘﻮل ﺷﻴﻨﺎر اﻟﺬي ﻳﻌﻤﻞ ﺣﺎﻟﻴـ ﺎً ﰲ ﻣﺮﻛـﺰ ﻋﻠـﻢ اﻷﺣﻴـﺎء اﻟﻔﻠﻜـﻲ ﰲ ﻣﺪرﻳ ـﺪ ﺑﺈﺳـﺒﺎﻧﻴﺎ :» أﺗـﺬﻛﺮ أﻧﻨـﻲ ﺣﻈﻴـﺖ ﺑﻠﺤﻈــﺔ اﻛﺘﺸﺎف ﻋﻨﺪﻣﺎ ﻛﻨـﺖ أﻗـﺮأ ﻛﺘﺎﺑـ ﺎً ﺑﻌﻨـﻮان : » ﻣﺎذا ﻟﻮ ﻛﺎن اﻟﻨﺠﻢ ﻣﻐﻨﺎﻃﻴﺴﻴ .«؟ﺎً اﻧﻄﻠــﻖ ﺷـﻴﻨﺎر وﻓﺮﻳﻘ ـﻪ ﻟﺪراﺳ ـﺔ اﻟ ـﻨﺠﻢ ﺑﺎﺳﺘﺨﺪام ﻣﻨﺸﺄت ﻋﻠﻤﻴﺔ . ﺣﻮل اﻟﻌﺎﻟﻢ