Free Astronomy Magazine July-August 2024 ARABIC VERSION

ed by Carlos Saffe of the Institute of Astronomical, Earth and Space Sciences (ICATE-CONICET) in Ar- gentina, the team used the Gemini South telescope in Chile, one half of the International Gemini Observa- tory, supported in part by the U.S. National Science Foundation and operated by NSF NOIRLab. With the new, precise Gemini High Resolu- tion Optical SpecTrograph (GHOST) the team studied the different wavelengths of light, or spectra, given off by a pair of giant stars, which revealed significant differ- ences in their chemical make-up. “GHOST’s extremely high-quality spectra offered unprecedented res- olution − said Saffe − allowing us to measure the stars’ stellar parame- ters and chemical abundances with the highest possible precision.” These measurements revealed that one star had higher abundances of heavy elements than the other. To disentangle the origin of this dis- crepancy, the team used a unique approach. Previous studies have proposed three possible explanations for ob- served chemical differences be- tween binary stars. Two of them involve processes that would oc- cur well into the stars’ evolution: atomic diffusion, or the settling of chemical elements into gradient lay- ers depending on each star’s tem- perature and surface gravity; and the engulfment of a small, rocky JULY-AUGUST 2024 ﻣﺠﻠﺔ FreeAstronomy ﺎﻟﻌﺮ ﺔ 39 ﺑﻘﻴﺎدة ﻛﺎرﻟﻮس ﺳﺎﰲ ﻣﻦ ﻣﻌﻬﺪ ﻋﻠﻮم اﻟﻔﻠﻚ واﻷرض واﻟﻔﻀﺎء (ICATE-CONICET) ﰲ اﻷرﺟﻨﺘــ اﺳــﺘﺨﺪم اﻟﻔ ﺮﻳــﻖ ﺗﻠﺴــﻜﻮب ﺟﻴﻤﻴﻨﻲ ﺳـﺎوث ﰲ ﺗﺸـﻴﲇ ﺿـﻤﻦ ﻣﺮﺻـﺪ ﺟﻴﻤﻴﻨﻲ اﻟﺪوﱄ ﺑﺪﻋﻢ ﺟﺰﺋﻲ ﻣـﻦ ﻣﺆﺳﺴـﺔ اﻟﻌﻠﻮم اﻟﻮﻃﻨﻴﺔ اﻷﻣﺮﻳﻜﻴﺔ وﻳـﺪﻳﺮه ﻣﺨﺘـﱪ ﻧﻮﻳﺮﻻب اﻟﺘﺎﺑﻊ ﺆ ﺳﺴﺔ اﻟﻌﻠـﻮم اﻟﻮﻃﻨﻴـﺔ اﻷﻣﺮﻳﻜﻴﺔ ﻗﺎم اﻟﻔﺮﻳﻖ ﺑﺎﺳـﺘﺨﺪام ﻣﻄﻴـﺎف اﻟﺒـ ﺟﻴﻤﻴﻨـﻲ ـ ﴫي اﻟـﺪﻗﻴﻖ ﻋـﺎﱄ اﻟﺪﻗـﺔ ( ﻏﻮﺳﺖ ) اﻟﺠﺪﻳﺪ ﻟـ ﺪراﺳﺔ اﻷﻃ ﻮ ـ ال ا ﻮﺟﻴﺔ ا ﺨﺘﻠﻔﺔ ﻟﻠﻀﻮء أو اﻷﻃﻴﺎف اﻟﺼـﺎدرة ﻋـﻦ ﺛﻨﺎﺋﻲ ﻣﻦ اﻟﻨﺠﻮم اﻟﻌﻤﻼﻗﺔ ﻣﻤﺎ ﻛﺸﻒ ﻋـﻦ ا ﺧﺘﻼﻓﺎت ﻛﺒ ة ﰲ ﺗﺮﻛﻴﺒﻬﺎ اﻟﻜﻴﻤﻴﺎﺋﻲ . إن أ ﻃﻴﺎفﻻ ا ﻠﺘﻘﻄﺔ ﺑﻮاﺳـﻄﺔ ) ( ﻏﻮﺳـﺖ ﻋﺎﻟﻴﺔ اﻟﺠﻮدة ﻗﺪﻣﺖ دﻗﺔ ﻏـ ﻣﺴـﺒﻮﻗﺔ - ﻛﻤﺎ ﻗﺎل ﺳﺎﰲ - ﻣﻤـﺎ ﻳﺴـﻤﺢ ﻟﻨـﺎ ﺑﻘﻴـﺎس ا ﻌﻠﻤــﺎت اﻟﻨﺠﻤﻴــﺔ ﻟﻠﻨﺠــﻮم واﻟــﻮﻓﺮة اﻟﻜﻴﻤﻴﺎﺋﻴﺔ ﺑﺄﻋﲆ دﻗﺔ ﻣﻤﻜﻨﺔ وﻛﺸﻔﺖ ﻫﺬه اﻟﻘﻴﺎﺳﺎت أن أﺣﺪ اﻟﻨﺠﻮم ﻟﺪﻳﻪ وﻓـﺮة أﻛـﱪ اﻟﺜﻘﻴﻠﺔ ﻣﻘ ﴏ ﻣﻦ اﻟﻌﻨﺎ ـ ﺎرﻧﺔ ﺑﺎﻟﻨﺠﻢ اﻵﺧﺮ ﻟﻜﺸﻒ أﺻﻞ ﻫﺬا اﻟﺘﻨﺎﻗﺾ اﺳﺘﺨﺪم اﻟﻔﺮﻳﻖ ﻧﻬﺠًﺎ ﻓﺮﻳﺪًا . اﻗﱰﺣﺖ دراﺳﺎت ﺳﺎﺑﻘﺔ ﺛﻼﺛﺔ ﺗﻔﺴ ات ﻣﺤﺘﻤﻠﺔ ﻟﻼﺧﺘﻼﻓﺎت اﻟﻜﻴﻤﻴﺎﺋ ﻴـﺔ ا ﺮﺻـﻮدة ﺑـ اﻟﻨﺠـﻮم اﻟﺜﻨﺎﺋﻴـﺔ ﺗﺘﻀـﻤﻦ اﺛﻨﺘﺎن ﻣﻨﻬﺎ ﻋﻤﻠﻴﺎت ﻗﺪ ﺗﺤﺪث ﺧ ﻄﻮر ﻼل ﺗ اﻟﻨﺠــﻮم : اﻻﻧﺘﺸــﺎر اﻟــﺬري أو اﺳــﺘﻘﺮار اﻟﻌﻨﺎﴏ اﻟ ﻜﻴﻤﻴﺎﺋﻴـﺔ ﰲ ﻃﺒﻘـﺎت ﻣﺘﺪرﺟـﺔ اﻋﺘﻤﺎد ﻋﲆ اً درﺟﺔ ﺣﺮارة ﻛﻞ ﻧﺠﻢ وﺟﺎذﺑﻴﺔ ﺳﻄﺤﻪ واﺑﺘﻼع ﻛﻮﻛﺐ ﺻﺨﺮي ﺻـﻐ ﻗـﺪ ﻳﺴﺒﺐ اﺧﺘﻼﻓﺎت ﻛﻴﻤﻴﺎﺋﻴﺔ ﰲ ﺗﻜﻮﻳﻦ اﻟﻨﺠﻢ - ﻳﻮﻟﻴﻮ ﺃﻏﺴﻄﺲ 2 0 2 4 A