Free Astronomy Magazine September-October 2023 ARABIC VERSION

planet-forming disks go through a period of such intense UV radiation, since stars tend to form in groups that often include massive, UV-pro- ducing stars. Typically, UV radiation is expected to destroy complex organic molecules, in which case the discovery of CH 3 + might seem to be a surprise. How- ever, the team predicts that UV radi- ation might actually provide the necessary source of energy for CH 3 + to form in the first place. Once formed, it then promotes additional chemical reactions to build more complex carbon molecules. Broadly, the team notes that the molecules they see in d203-506 are quite different from typical proto- planetary disks. In particular, they could not detect any signs of water. “This clearly shows that ultraviolet radiation can completely change the chemistry of a protoplanetary disk. It might actually play a critical role in the early chemical stages of the origins of life,” elaborated Olivier Berné of the French National Centre for Scientific Research in Toulouse, lead author of the study.   MIRI Mid-Infrared MIRI and NIRCam ﻣﺠﻠﺔ FreeAstronomy ﺎﻟﻌﺮ ﺔ 45 - ﺳﺒﺘﻤﺒﺮ ﺃﻛﺘﻮﺑﺮ 2 0 2 3 ﻓﻮق اﻟﺒﻨﻔﺴﺠﻴﺔ . ﻋﺎدة ﻣﻦ ا ﺘﻮﻗﻊ أن ﺗﺪﻣﺮ اﻷﺷــﻌﺔ ﻓــﻮق اﻟﺒﻨﻔﺴــﺠﻴﺔ اﻟﺠﺰﻳﺌــﺎت اﻟﻌﻀﻮﻳﺔ ا ﻌﻘﺪة، وﰲ ﻫﺬه اﻟﺤﺎﻟﺔ ﻗﺪ ﻳﺒـﺪو اﻛﺘﺸﺎف CH3 + ﺑﻤﺜﺎﺑﺔ ﻣﻔﺎﺟﺄة وﻣﻊ ذﻟـﻚ ﻳﺘﻮﻗﻊ اﻟﻔﺮﻳﻖ أن اﻷﺷﻌﺔ ﻓﻮق اﻟﺒﻨﻔﺴـﺠﻴﺔ ﻗﺪ ﺗﻮﻓﺮ ﺑﺎﻟﻔﻌﻞ ﻣﺼﺪر اﻟﻄﺎﻗﺔ اﻟﻀ ﺔ ﺮورﻳ ـ ﻟﺘﻜــﻮﻳﻦ CH3 + ﰲ ا ﻘــﺎم اﻷول وﺑﻤﺠــﺮد ﺗﻜﻮﻳﻨﻪ ﻓﺈﻧﻪ ﻳﻌـﺰز اﻟﺘﻔـﺎﻋﻼت اﻟﻜﻴﻤﻴﺎﺋﻴـﺔ ـــــــ ﻓﺈن اﻟﻨﻈﺎم ﻳﺘﻌﺮض ﻟﻘﺼـﻒ ﻣـﻦ اﻷﺷـﻌﺔ ﻓـﻮق اﻟﺒﻨﻔﺴـﺠﻴﺔ اﻟﻘﻮﻳـﺔ اﻟﻘﺎدﻣـﺔ ﻣـﻦ اﻟﻨﺠــﻮم اﻟﻘﺮﻳﺒ ــﺔ اﻟﺴـــﺎﺧﻨﺔ واﻟﻔﺘﻴـــﺔ واﻟﻀــﺨﻤﺔ . ﻳﻌﺘﻘــﺪ اﻟﻌﻠﻤــﺎء أن ﻣﻌﻈــﻢ اﻷﻗﺮاص ا ﻜﻮﻧﺔ ﻟﻠﻜﻮاﻛﺐ ﺗﻤﺮ ﺑﻔـﱰة ﻣـﻦ اﻷﺷﻌﺔ ﻓـﻮق اﻟﺒﻨﻔﺴـﺠﻴﺔ ا ﻜﺜﻔـﺔ، ﺣﻴـﺚ ﺗﻤﻴﻞ اﻟ ﻨﺠﻮم إﱃ اﻟﺘﺸﻜﻞ ﰲ ﻣﺠﻤﻮﻋﺎت ﻏﺎﻟﺒ ﺎً ﻣﺎ ﺗﺘﻀﻤﻦ ﻧﺠﻮﻣ ﺎً ﺿﺨﻤﺔ ﻣﻨﺘﺠﺔ ﻟﻸﺷـﻌﺔ ﻓﻮق اﻟﺒﻨﻔﺴﺠﻴﺔ . اﻹﺿﺎﻓﻴ ﺔ ﻟﺒﻨﺎء ﺟﺰﻳﺌﺎت ﻛﺮﺑﻮن أﻛﺜﺮ ﺗﻌﻘﻴﺪ .اً ﻻﺣﻆ اﻟﻔﺮﻳﻖ أن اﻟﺠﺰﻳﺌـﺎت ﰲ d203-506 ﺗﺨﺘﻠﻒ ﺗﻤﺎﻣ ﺎً ﻋﻦ اﻷ ﻗﺮاص اﻟﻜﻮﻛﺒﻴﺔ اﻷوﻟﻴﺔ ﺣﻴﺚ ﻟﻢ ﻳﺘﻤﻜﻨﻮا ﻣﻦ اﻛﺘﺸﺎف أي ﻋﻼﻣـﺎت ﻟﻮﺟﻮد ا ﺎء ﻳﻮﺿﺢ ﻫﺬا و أن اﻷﺷـﻌﺔ ﻓـﻮق اﻟﺒﻨﻔﺴﺠﻴﺔ ﻳﻤﻜﻦ أن ﺗﻐـ ﺗﻤﺎ ﻣـﺎً ﻛﻴﻤﻴـﺎء ﻗﺮص اﻟﻜﻮاﻛﺐ اﻷوﻟﻴﺔ وﺗﺆدي اً دور ﰲ ﻣﻬﻤﺎ ا ﺮاﺣﻞ اﻟﻜﻴﻤﻴﺎﺋﻴﺔ ا ﺒﻜﺮة ﻷﺻﻮل اﻟﺤﻴﺎة .