Free Astronomy Magazine July-August 2024 ARABIC VERSION

planet, which would introduce chemical variations in a star’s composition. The third possible expla- nation looks back at the beginning of the stars’ formation, suggesting that the differences originate from primordial, or pre-existing, areas of nonuniformity within the molecular cloud. In simpler terms, if the molecu- lar cloud has an un- even distribution of chemical elements, then stars born within that cloud will have different compositions de- pending on which elements were avail- able at the location where each formed. So far, studies have concluded that all three explanations are probable; however, these stud- ies focused solely on main-sequence binaries. The ‘main-sequence’ is the stage where a star spends most of its existence, and the majority of stars in the Universe are main-se- quence stars, including our Sun. In- stead, Saffe and his team observed a binary consisting of two giant stars. These stars possess extremely deep and strongly turbulent exter- nal layers, or convective zones. Owing to the properties of these thick convective zones, the team was able to rule out two of the three possible explanations. The continuous swirling of fluid within the convective zone would make it difficult for material to set- tle into layers, meaning giant stars are less sensitive to the effects of atomic diffusion — ruling out the first explanation. The thick external layer also means that a planetary engulfment would not change a star’s composition much since the ingested material would rapidly be diluted — ruling out the second ex- planation. This leaves primordial in- homogeneities within the molecular cloud as the confirmed explanation. “This is the first time astronomers have been able to confirm that dif- ferences between binary stars begin at the earliest stages of their forma- tion,” said Saffe. “Using the precision-measurement capabilities provided by the GHOST instrument, Gemini South is now col- lecting observations of stars at the end of their lives to reveal the envi- ronment in which they were born,” says Martin Still, NSF program di- rector for the International Gemini Observatory. “This gives us the ability to explore how the conditions in which stars form can influ- ence their entire ex- istence over millions or billions of years.” Three consequences of this study are of particular signifi- cance. First, these results offer an ex- planation for why astronomers see bi- nary stars with such different planetary systems. “Different planetary systems could mean very dif- ferent planets — rocky, Earth-like, ice giants, gas giants — that orbit their host stars at different distances and where the potential to support life might be very different,” said Saffe. Second, these results pose a crucial challenge to the concept of chemical tagging — using chemical composition to identify stars that came from the same environment or stellar nursery — by showing that stars with differ- ent chemical compositions can still have the same origin. Finally, observed differences previ- ously attributed to planetary im- pacts on a star’s surface will need to be reviewed, as they might now be seen as having been there from the very beginning of the star’s life. “By showing for the first time that pri- mordial differences really are pres- ent and responsible for differences between twin stars, we show that star and planet formation could be more complex than initially thought,” said Saffe. “The Universe loves diversity!”       اﻟﺸـﺮﻂ اﻟﻤﻠـﻮن ﻟﻤﺠـﺮة در اﻟﺘ ﺎﻧـﺔ ﻈﻬـﺮ ﻓـﻮق ﺗﻠﺴـ ﻮب ﺳـﺎوث ـ ﺟ ﻤ ﻳ ﻠـﻎ اﻟـﺬ ﻗﻄـﺮﻩ 8.1 اً ﻣ ﻟﻌﻠـﻢ اﻟﻔﻠـﻚ اﻟ اﻟﺘﺎﺑﻊ ﻟﻠﻤﺨﺘـ اﻟـﻮﻃ ﺼـﺮيواﻷﺷـﻌﺔ ﺗﺤـﺖ اﻟـ ـ ) ﻤﺮاء ﻧـﻮﻳﺮﻻب ( اﻟﺘـﺎﺑﻊ ــﺔ ﻟﻤﺆﺳﺴــﺔ اﻟﻌﻠـﻮم اﻟﻮﻃﻨ ﺗﺼــﻮر ﻘﻌــ ﻓــﻲﻫــﺬﻩ اﻟﺼــﻮرة اﻟﻤﺬﻫﻠــﺔ اﻟــ ﺎ ﻻﻣﻌــﺔ ﻣــﻦ اﻟﻨﺠــﻮم ﺗﺘﺨﻠﻠﻬﺎ ﻣﻤﺮات ﻣﺘﻌﺮﺟﺔ ﻣﻦ اﻟﻐ ﺎر . ﻘﻊ ﻣﺮﻛﺰ اﻟﻤﺠﺮة ﻣ ﺎﺷﺮة ﻓﻮق اﻟﺘﻠﺴـ ﻮب و ﺸـ ﻞ إﻃـﺎر اً ﻟﻮاﺣﺪ ﻣﻦ أﻗﻮى اﻟﻤﺮاﺻﺪ اﻟﻔﻠﻜ ﺔ ﻓﻲ ﻧﺼﻒ اﻷرض ـاﻟ . ﺠﻨﻮﺑﻲ ﻣﺠﻠﺔ FreeAstronomy ﺎﻟﻌﺮ ﺔ 40 أﻣــﺎ اﻟﺘﻔﺴــ اﻟﺜﺎﻟــﺚ ا ﺤﺘﻤﻞ ﻓ ﺟﻊ إﱃ ﺑﺪاﻳﺔ ﺗﺸــﻜﻞ اﻟﻨﺠــﻮم، ﻣﻤــﺎ ﻳﺸ إﱃ أن اﻻﺧﺘﻼﻓـﺎت ﺗﻨﺸﺄ ﻣﻦ ﻣﻨﺎﻃﻖ ﺑﺪاﺋﻴـﺔ أو ﻣﻮﺟﻮدة ﻣﺴﺒﻘ ﺎً ﻣـﻦ ﻋــﺪم اﻻﻧﺘﻈــﺎم داﺧــﻞ اﻟﺴـــﺤﺎﺑﺔ اﻟﺠﺰﻳﺌﻴـــﺔ وﺑﻌﺒــﺎرات أﺑﺴــﻂ إذا ﻛﺎﻧﺖ اﻟﺴﺤﺎﺑﺔ اﻟﺠﺰﻳﺌﻴﺔ ﺗﺤﺘﻮي ﻋﲆ ﺗﻮزﻳ ﻊ ﻏـ ﻣﺘﺴـــﺎوي ﻟﻠﻌﻨـــﺎﴏ اﻟﻜﻴﻤﻴﺎﺋﻴﺔ ﻓﺈن اﻟﻨﺠـﻮم ا ﻮﻟــﻮدة داﺧــﻞ ﺗﻠــﻚ اﻟﺴـﺤﺎﺑﺔ ﺳـﻴﻜﻮن ﻟﻬـﺎ ﺗﺮﻛﻴﺒـــﺎت ﻣﺨﺘﻠﻔـــﺔ اﻋﺘﻤـﺎدا ﻋـﲆ اﻟﻌﻨـﺎﴏ اﻟﺘـﻲ ﻛﺎﻧـﺖ ﻣﺘـﻮﻓﺮة ﰲ ا ﻮﻗﻊ اﻟﺬي ﺗﺸﻜﻠﺖ ﻓﻴﻪ ﻛــﻞ ﻣﻨﻬــﺎ . ﺣﺘــﻰ اﻵن ﺧﻠﺼﺖ اﻟﺪراﺳﺎت إﱃ أن اﻟﺘﻔﺴـــ ات اﻟﺜﻼﺛـــﺔ ﺟﻤﻴﻌﻬﺎ ﻣﺤﺘﻤﻠـ ﺔ وﻣـﻊ ذﻟـــﻚ رﻛـــﺰت ﻫـــﺬه اﻟﺪراﺳـﺎت ﻓﻘ ـﻂ ﻋ ـﲆ ﺛﻨﺎﺋﻴﺎت اﻟﺘﺴﻠﺴﻞ اﻟﺮﺋﻴﺴـ .ﻲـ إن ا ﻘﺼـﻮد ﺑﺎ ﻟﺘﺴﻠﺴﻞ اﻟﺮﺋ ا ﻫﻮ ﻴﴘـ ﺮﺣﻠﺔ اﻟﺘﻲ ﻳﻘﴤ ﻓﻴﻬ ﺎ اﻟﻨﺠﻢ ﻣﻌﻈﻢ ﻓـﱰة وﺟـﻮده وﻏﺎﻟﺒﻴـﺔ اﻟﻨﺠـﻮم ﰲ اﻟﻜـﻮن ﻫـﻲ ﻧﺠـﻮم اﻟﺘﺴﻠﺴـﻞ اﻟﺮﺋﻴﴘ ﺑﻤﺎ ﰲ ذﻟﻚ ﺷﻤﺴﻨﺎ . ﺑﺪﻻً ﻣﻦ ذﻟﻚ ﻻﺣـﻆ ﺳـﺎﰲ وﻓﺮﻳﻘـﻪ ﺛﻨﺎﺋﻴـﺎً ﻳﺘﻜﻮن ﻣﻦ ﻧﺠﻤ ﻋﻤﻼﻗ . ﺗﻤﺘﻠﻚ ﻫﺬه اﻟﻨﺠﻮم ﻃﺒﻘﺎت ﺧ ﺎرﺟﻴﺔ ﻋﻤﻴﻘﺔ ﻟﻠﻐﺎﻳﺔ وﻣﻀﻄﺮﺑﺔ ﺑﺸﺪة أو ﻣﻨﺎﻃﻖ اﻟﺤﻤـﻞ اﻟﺤﺮاري . اً ﻧﻈﺮ ﻟﺨﺼﺎﺋﺺ ﻣﻨﺎﻃﻖ اﻟﺤﻤـﻞ اﻟﺤـﺮاري اﻟﺴﻤﻴﻜﺔ ﻫﺬه ﺗﻤﻜﻦ اﻟﻔﺮﻳﻖ ﻣـﻦ اﺳـﺘﺒﻌﺎد اﺛﻨ ﻣﻦ اﻟﺘﻔﺴ ات اﻟﺜﻼﺛﺔ ا ﺤﺘﻤﻠﺔ . إن اﻟﺪوران ا ﺴﺘﻤﺮ ﻟﻠﺴﻮاﺋﻞ د اﺧﻞ ﻣﻨﻄﻘـﺔ اﻟﺤﻤﻞ اﻟﺤﺮاري ﻣﻦ ﺷـﺄﻧﻪ أن ﻳﺠﻌـﻞ ﻣـﻦ اﻟﺼ ﻌﺐ ﻋﲆ ا ﻮاد أن ﺗﺴﺘﻘﺮ ﰲ ﻃﺒﻘﺎت ﻣﻤﺎ ﻳﻌﻨﻲ أن اﻟﻨﺠﻮم اﻟﻌﻤﻼﻗـﺔ أﻗـﻞ ﺣﺴﺎﺳـﻴﺔ ﻟﺘـﺄﺛ ات اﻻﻧﺘﺸـﺎر اﻟـﺬري ﻣﻤـﺎ ﻳﺴــﺘﺒﻌﺪ اﻟﺘﻔﺴــ اﻷول إن . اﻟﻄﺒﻘــﺔ اﻟﺨﺎرﺟﻴــﺔ اﻟﺴﻤﻴﻜﺔ ﺗﻌﻨﻲ أﻳﻀًﺎ أن اﺑﺘﻼع اﻟﻜﻮاﻛﺐ ﻟﻦ اﻟﺴﻤﻴﻜﺔ ﺗﻌﻨﻲ أﻳﻀ ﺎ أن اﺑﺘﻼع اﻟﻜﻮاﻛﺐ ﻟـﻦ ﻳﻐ ﺗﺮﻛﻴﺒﺔ اﻟﻨﺠﻢ ﻛﺜ اً ﻷن ا ﺎدة ا ﺒﺘﻠﻌـﺔ ـ ﺳﺘﺨﻔﻒ ﺑ ﴪﻋﺔ ﻣﻤـﺎ ﻳﺴـ ﺘﺒﻌﺪ اﻟﺘﻔﺴـ اﻟﺜﺎﻧﻲ ﻫﺬا ﻳـﱰك ﻋـﺪم اﻟﺘﺠـﺎﻧﺲ اﻟﺒـﺪاﺋﻲ داﺧﻞ اﻟﺴﺤﺎﺑﺔ اﻟﺠﺰﻳﺌﻴﺔ ﻛﺘﻔﺴ ﻣﺆﻛﺪ . ﻗﺎل ﺳﺎﰲ إن : ﻫـﺬه ﻫـﻲ ا ـﺮة اﻷوﱃ اﻟﺘـﻲ ﻳﺘﻤﻜﻦ ﻓﻴﻬﺎ ﻋﻠﻤـﺎء اﻟﻔﻠـﻚ ﻣـﻦ ﺗﺄﻛﻴـﺪ أن اﻻﺧﺘﻼﻓـﺎت ﺑـ اﻟﻨﺠـﻮم اﻟﺜﻨﺎﺋﻴـﺔ ﺗﺒـﺪأ ﰲ ا ﺮاﺣﻞ اﻷوﱃ ﻣﻦ ﺗﻜﻮﻳﻨﻬﺎ ." ﻳﻘﻮل ﻣﺎرﺗﻦ ﺳﺘﻴﻞ ﻣﺪﻳﺮ ﺑﺮﻧﺎﻣﺞ ﻣﺆ ﺳﺴـﺔ اﻟﻌﻠﻮم اﻟﻮﻃﻨﻴﺔ ﰲ ﻣﺮﺻﺪ ﺟﻴﻤﻴﻨﻲ اﻟـﺪوﱄ ": ﺑﺎﺳﺘﺨﺪا م إﻣﻜﺎﻧﻴﺎت اﻟﻘﻴﺎس اﻟﺪﻗﻴﻘﺔ اﻟﺘـﻲ ﻳ ﻮﻓﺮﻫﺎ (. ﻏﻮﺳﺖ ) ﻣﻄﻴﺎف ﻳﻘﻮم ﺗﻠﺴﻜﻮب ﺟﻴﻤﻴﻨﻲ ﺳﺎوث اﻵن ﺑﺠﻤـﻊ أرﺻﺎد اﻟﻨﺠﻮم ﰲ ﻧﻬﺎﻳﺔ ﺣﻴﺎﺗﻬ ﺎ ﻟﻠﻜﺸﻒ ﻋﻦ اﻟﺒﻴﺌﺔ اﻟﺘﻲ ﺎ و ﻓﻴﻬ وﻟﺪت ﻫﺬا ﻳﻤﻨﺤﻨﺎ اﻟﻘﺪرة ﻋﲆ اﺳﺘﻜﺸﺎف ﻛﻴﻒ ﻳﻤﻜﻦ ﻟﻠﻈﺮوف اﻟﺘـﻲ ﺗﺘﺸﻜﻞ ﻓ ﻴﻬﺎ اﻟﻨﺠﻮم أن ﺗﺆﺛﺮ ﻋﲆ وﺟﻮدﻫـﺎ ﺑﺄﻛﻤﻠﻪ ﻋﲆ ﻣﺪى ﻣﻼﻳ أو ﻣﻠﻴﺎرات اﻟﺴﻨ . ﻫﻨﺎك ﺛﻼث ﻧﺘـﺎﺋﺞ ﻟﻬـﺬه اﻟﺪراﺳــﺔ ﻟﻬــﺎ أﻫﻤﻴــﺔ . ﺧﺎﺻﺔ أوﻻً إن ﻫﺬه اﻟﻨﺘﺎﺋﺞ ﺗﻘﺪم اﻟﻨﺘﺎﺋﺞ ﺗﻔﺴـ اً ﻟﺴـﺒﺐ رؤﻳﺔ ﻋﻠﻤﺎء اﻟﻔﻠﻚ ﻟﻨﺠﻮم ﺛﻨﺎﺋﻴـﺔ ﻟﻬــﺎ ﻣﺜـﻞ ﻫـﺬه اﻷﻧﻈﻤـــﺔ اﻟﻜﻮﻛﺒﻴـــﺔ ا ﺨﺘﻠﻔﺔ . ﺗﻤﺎﻣﺎً ﻗﺎل ﺳـﺎﰲ " : ﻗـﺪ ﺗﻌﻨـﻲ اﻷﻧﻈﻤـــﺔ اﻟﻜﻮﻛﺒﻴـــﺔ ا ﺨﺘﻠﻔﺔ وﺟـﻮد ﻛﻮاﻛـﺐ ﻣﺨﺘﻠﻔﺔ ﺗﻤﺎﻣﺎً ﺻـﺨﺮﻳﺔ أو ﺷــﺒﻴﻬﺔ ﺑــﺎﻷرض أو ﻛﻮاﻛﺐ ﻋﻤﺎﻟﻘﺔ ﺟﻠﻴﺪﻳـﺔ أو ﻛﻮاﻛﺐ ﻋﻤﺎﻟﻘﺔ ﻏﺎزﻳﺔ ﺗــﺪور ﺣــﻮل ﻧﺠﻮﻣﻬــﺎ ا ﻀﻴﻔﺔ ﻋـﲆ ﻣﺴـﺎﻓﺎت ﺨﺘﻠﻔﺔ ﻣ وﺣﻴﺚ ﻗﺪ ﺗﻜﻮن إﻣﻜﺎﻧﻴ ـﺔ دﻋ ـﻢ اﻟﺤﻴ ـﺎة ﻣﺨﺘﻠﻔﺔ ﺗﻤﺎﻣ ". ﺎً ﺛﺎﻧﻴﺎً ﺗﺸﻜﻞ ﻫﺬه اﻟﻨﺘﺎﺋﺞ ﺎً ﺗﺤﺪﻳ ﺎً ﺣﺎﺳـﻤ ﻔﻬـﻮم اﻟﻌﻼﻣﺎت اﻟﻜﻴﻤﻴﺎﺋﻴﺔ . ﻟﻘﺪ اﺳـﺘﺨﺪام اﻟﱰﻛﻴـﺐ اﻟﻜﻴﻤﻴﺎﺋﻲ وﻟﻜﻦ ﺑﻬﺪف اﻟﺘﻌﺮف ﻋﲆ اﻟﻨﺠﻮم اﻟﺘﻲ ﺟﺎءت ﻣﻦ ﻧﻔﺲ اﻟﺒﻴﺌـﺔ أو اﻟﺤﻀـﺎﻧﺔ اﻟﻨﺠﻤﻴﺔ وذﻟﻚ ﻣﻦ ﺧﻼل اﻟﻘﻴﺎم ﺑ ﺈﻇﻬـﺎر أن اﻟﻨﺠﻮم اﻟﺘﻲ ﻛﺸﻒ اﻟﺘﺤﻠﻴﻞ اﻟﻄﻴﻔـﻲ أﻧﻬـﺎ ذات ﺗﺮﻛﻴﺒﺎت ﻛﻴﻤﻴﺎﺋﻴﺔ ﻣﺨﺘﻠﻔـﺔ ﻳﻤﻜـﻦ أن ﻳﻜﻮن ﻟﻬﺎ ﻧﻔﺲ اﻷﺻﻞ . أﺧ اً ﻳﺠﺐ ﻋـﲆ ا ﺠﺘﻤـﻊ اﻟﻌﻠﻤـﻲ إﻋـﺎدة اﻟﻨﻈﺮ ﰲ اﻻﺧﺘﻼﻓﺎت ا ﺮﺻﻮدة ﺑ اﻟﻨﺠـﻮم و اﻟﺘـﻲ ﻛﺎﻧ ـﺖ ﺗُﻌــﺰى ﺳـﺎﺑﻘ إﱃ ﺎً ﺗـﺄﺛ ات اﻟﻜﻮاﻛﺐ ﻋﲆ ﺳﻄﺢ اﻟﻨﺠﻢ ﺣﻴﺚ ﻗـﺪ ﻳُﻨﻈـﺮ إﻟﻴﻬﺎ اﻵن ﻋﲆ أﻧﻬﺎ ﻛﺎﻧﺖ ﻣﻮﺟﻮدة ﻣﻨﺬ ﺑﺪاﻳﺔ ﺗﺎرﻳﺦ . ﺣﻴﺎة اﻟﻨﺠﻢ أﺿﺎف : " ﺳﺎﰲ ﻣﻦ ﺧﻼل إﻇﻬﺎر اﻟﻌﻠﻤﺎء ﻷول ﻣﺮة أن اﻻ ﺧﺘﻼﻓﺎت اﻟﺒﺪاﺋﻴﺔ ﻣﻮﺟﻮدة ﺑﺎﻟﻔﻌﻞ وﻫﻲ ﻣﺴﺆوﻟﺔ ﻋﻦ اﻻﺧﺘﻼﻓﺎت ا ﺸﺎﻫﺪة ﺑ اﻟﻨﺠﻮم اﻟﺘﻮ ﻢاﺋ ﻓﺈﻧﻨﺎ ﻧﻈﻬﺮ أدﻟﺔ ﺑﺄ ن ﺗﻜﻮﻳﻦ اﻟﻨﺠﻮم و اﻟﻜﻮاﻛـﺐ ﻳﻤﻜـﻦ أن ﻳﻜـﻮن أﻛﺜـﺮ اً ﺗﻌﻘﻴﺪ ﻣﻤﺎ ﻛﺎن ﻳﻌﺘﻘﺪ ﰲ اﻟﺒﺪاﻳـﺔ ﻓـ ﺎﻟﻜﻮن ﻳﺤﺐ اﻟﺘﻨﻮع "! - ﻳﻮﻟﻴﻮ ﺃﻏﺴﻄﺲ 2 0 2 4 [International Gemini Observatory/NSF’s NOIRLab/AURA/KwonO Chul]