Free Astronomy Magazine November-December 2023 ARABIC VERSION

question now might be how the ab- sence or presence of these PAHs – or the processes that eventually pro- duce them – changes any aspect of the star formation process. Finally, it is noteworthy that these compli- cated molecules formed in a rela- tively short period of time on cosmological scales, for which the reason why such complexity in mo- tive species formed in the wispy voids of molecular clouds in deep space, where simple and complex molecules alike have little protec- tion from the pummeling UV radia- tion of stars in their vicinity. While something like methyl cation would interact both quickly and highly re- actively in environments like our own atmosphere or in the beaker of a reaction vessel in some laboratory, the very low density of molecules in the interstellar medium, even when contained in relatively dense molec- ular clouds in these same regions, means that these irradiated mole- cules can persist for very long peri- ods of time, making their detection possible. The methyl cation, a charged species made reactive by the desire for this carbon to make another chemical bond and neutral- ize its positive charge, adds that in- cremental carbon atom to some increasingly large molecule that, over millions of years and uncount- able numbers of interactions with more photons and other molecules, eventually can make the larger mol- ecules we are now also able to de- tect more reliability thanks to having an excellent infrared tele- scope like the JWST in space. The study, by Olivier Berné of the French National Center for Scientific Research and co-workers from Euro- pean, US, and Japanese organiza- tions, reports that methyl cation was detected in d203-506, one of the numerous protoplanetary disks identified in the Orion Nebula about 1350 light years distant. What was once simply a star-form- ing region of atomic and molecular nebulosity was discovered with the Hubble Space Telescope to also be host to protoplanetary systems now condensing these molecular clouds into larger molecules at one scale and protoplanets at another. The reactivity and chemistry of methyl cation simply adds to the complex- NOVEMBER-DECEMBER 2023 ﻣﺠﻠﺔ FreeAstronomy ﺎﻟﻌﺮ ﺔ 13 ﻧﻮﻓﻤ - ﺒﺮ ﺩﻳﺴﻤﺒﺮ 2 0 2 3 واﻟﺴﺆال ا ﻄﺮوح اﻵن ﻫﻮ ﻛﻴﻒ ﻳﺆدي ﻏﻴﺎب أو وﺟﻮد ﻫـﺬه اﻟﻬﻴـﺪروﻛﺮﺑﻮﻧﺎت اﻟﻌﻄﺮﻳـﺔ ا ﺘﻌ ـﺪدة اﻟﺤﻠﻘ ـﺎت - أو اﻟﻌﻤﻠﻴ ـﺎت اﻟﺘ ـﻲ ﺗﻨﺘﺠﻬـﺎ ﰲ ﻧﻬﺎﻳــﺔ ا ﻄــﺎف إﱃ - ﺗﻐﻴـ أي ﺟﺎﻧﺐ ﻣﻦ ﺟﻮاﻧﺐ ﻋﻤﻠﻴﺔ ﺗﻜـﻮﻳﻦ اﻟﻨﺠـﻮم . أﺧ اً ﻣﻦ اﻟﺠﺪﻳﺮ ﺑﺎﻟﺬﻛﺮ أن ﻫﺬه اﻟﺠﺰﻳﺌـﺎت ا ﻌﻘﺪة ﺗﺸﻜﻠﺖ ﰲ ﻓﱰة زﻣﻨﻴﺔ ﻗﺼ ة ﻧﺴﺒﻴًﺎ ﻋﲆ ا ﻘﺎﻳﻴﺲ اﻟﻜﻮﻧﻴﺔ وﻟﻬـﺬا اﻟﺴـﺒﺐ ﻳﻌـﺪ ﺳـﺒﺐ ﺣـﺪوث ﻫـﺬا اﻟﺘﻌﻘﻴ ـﺪ ﰲ اﻟﻬﻴﺎﻛ ـﻞ اﻟﺠﺰﻳﺌﻴﺔ ﰲ وﻗﺖ ﻣﺒﻜـﺮ ﺟـﺪًا ﻣـﻦ ﺗـﺎرﻳﺦ اﻟﺠﺰﻳﺌﻴﺔ ﰲ وﻗﺖ ﻣﺒﻜـﺮ ﺟـﺪًا ﻣـﻦ ﺗـﺎرﻳﺦ اﻟﻜﻮن ﻟﻐﺰًا أﻳﻀًﺎ . اﻟﺴﺆال ا ﻄﺮ وح اﻵن ﻫﻮ ﻛﻴﻒ ﻳﺆدي ﻏﻴـﺎب أو وﺟﻮد ﻫـﺬه اﻟﻬﻴـﺪروﻛﺮﺑﻮﻧﺎت اﻟﻌﻄﺮﻳـﺔ ا ﺘﻌ ـﺪدة اﻟﺤﻠﻘ ـﺎت - أو اﻟﻌﻤﻠﻴ ـﺎت اﻟﺘ ـﻲ ﺗﻨﺘﺠﻬـﺎ ﰲ ﻧﻬﺎﻳـﺔ ا ﻄـﺎف - إﱃ ﺗﻐﻴـ أي ﺟﺎﻧﺐ ﻣﻦ ﺟﻮاﻧﺐ ﻋﻤﻠﻴﺔ ﺗﻜﻮﻳﻦ اﻟﻨﺠﻮم . أﺧ ًا، ﻣﻦ اﻟﺠﺪﻳﺮ ﺑﺎﻟﺬﻛﺮ أن ﻫﺬه اﻟﺠﺰﻳﺌﺎت ا ﻌﻘﺪة ﺗﺸﻜﻠﺖ ﰲ ﻓﱰة زﻣﻨﻴﺔ ﻗﺼ ة ﻧﺴﺒﻴًﺎ ﻋﲆ ا ﻘﺎﻳﻴﺲ اﻟﻜﻮﻧﻴﺔ، وﻟﻬﺬا اﻟﺴـﺒﺐ ﻳﻌـﺪ ﺎ ﻘﺑ ﺎﻳﻴﺲ اﻟﻜﻮﻧﻴﺔ وﻟﻬﺬا اﻟﺴﺒﺐ ﻳﻌﺪ ﺳـﺒﺐ ﺣﺪوث ﻫﺬا اﻟﺘﻌﻘﻴـ ﺪ ﰲ اﻟﻬﻴﺎﻛـﻞ اﻟﺠﺰﻳﺌﻴـﺔ ﰲ و وذﻟﻚ ﻗﺖ ﻣﺒﻜﺮ ﺟﺪاً ﻣﻦ ﺗـﺎرﻳﺦ اﻟﻜـﻮن أﻳﻀ اً ﻟﻐﺰ .ﺎً أﻓﺎدت دراﺳﺔ ﺛﺎﻧﻴﺔ ﻧُﴩت ﰲ ﻋﺪد 26 ﻳﻮﻧﻴﻮ ﻣﻦ ﻣﺠﻠﺔ ﻧﻴﺘﴩ ﻋﻦ ا ﻛﺘﺸﺎف أﺣـﺪ أﺑﺴـﻂ اﻟﺠﺰﻳﺌﺎت اﻟﻌﻀﻮﻳﺔ وﻫﻮ ﻟﺒﻨﺔ ﺑﻨﺎء ﺗﻔﺎﻋﻠﻴﺔ ﻟﺠﺰﻳﺌ ـﺎت أﻛﺜ ـﺮ ﺗﻌﻘﻴ ـﺪًا ﰲ ا ﻟﻮﺳـﻂ ﺑ ـ اﻟﻨﺠﻮم . ﻛﺎﺗﻴﻮن ا ﻴﺜﻴـﻞ CH3 + ﻫـﻮ ﻧـﻮع ﺷــﺪﻳ ﺪ اﻟﺘﻔﺎﻋــﻞ ﻳﺘﺸــﻜﻞ ﰲ اﻟﻔﺮاﻏــﺎت اﻟﻀـﻌﻴﻔﺔ ﻟﻠﺴـﺤﺐ اﻟﺠﺰﻳﺌﻴـﺔ ﰲ اﻟﻔﻀـﺎء اﻟﺴﺤﻴﻖ ﺣﻴﺚ ﺗﺘﻤﺘﻊ اﻟﺠﺰﻳﺌـﺎت اﻟﺒﺴـﻴﻄﺔ وا ﻌﻘﺪة ﻋﲆ ﺣﺪ ﺳﻮاء ﺑﺤﻤﺎﻳﺔ ﻗﻠﻴﻠـﺔ ﻣـﻦ اﻷﺷﻌﺔ ﻓﻮق اﻟﺒﻨﻔﺴﺠﻴﺔ اﻟﻀﺎرﺑﺔ ﻟﻠﻨﺠـﻮم ﰲ ا ﻨﺎﻃﻖ ا ﺠﺎورة ﻟﻬﺎ ﰲ ﺣ أن ﺷﻴﺌًﺎ ﻣﺜﻞ ﻛﺎﺗﻴﻮن ا ﻴﺜﻴﻞ ﻳﻤﻜﻦ أن ﻳﺘﻔﺎﻋـﻞ ﺑـ ـ ﴪﻋﺔ وﺑﺘﻔﺎﻋﻠ ﻴـﺔ ﻋﺎﻟﻴـﺔ ﰲ ﺑﻴﺌـﺎت ﻣﺜـﻞ ﻏﻼﻓﻨـﺎ اﻟﺠﻮي أو ﰲ ﻛﻮب وﻋﺎء اﻟﺘﻔﺎﻋـﻞ ﰲ ﺑﻌـﺾ ا ﺨﺘﱪات ﻓﺈن ﻛﺜﺎﻓﺔ اﻟﺠﺰﻳﺌﺎت ا ﻨﺨﻔﻀـﺔ ﺟﺪًا ﰲ اﻟﻮﺳﻂ ﺑـ اﻟﻨﺠﻤـﻲ ﺣﺘـﻰ ﻋﻨـﺪﻣﺎ ﺗﻜﻮن ﻣﻮﺟﻮدة ﰲ ﺟﺰﻳﺌـﺎت ﻛﺜﻴﻔـﺔ ﻧﺴـ ﺒﻴًﺎ اﻟﺴﺤﺐ ﰲ ﻫﺬه ا ﻨـﺎﻃﻖ ﻧﻔﺴـﻬﺎ ﻳﻌﻨـ ﻲ أن ﻫﺬه اﻟﺠﺰﻳﺌﺎت ا ﺸـ ﻌﺔ ﻳﻤﻜـﻦ أن ﺗ ﺴـﺘﻤﺮ ﻟﻔﱰات ﻃﻮﻳﻠﺔ ﺟ ﺪًا ﻣﻦ اﻟﺰﻣﻦ ﻣﻤـﺎ ﻳﺠﻌـﻞ اﻛﺘﺸﺎﻓﻬﺎ ﻣﻤﻜﻨًﺎ . ﻛﺎﺗﻴﻮن ا ﻴﺜﻴﻞ وﻫﻮ ﻧـﻮع ﻣﺸﺤﻮن ﻳﺼﺒﺢ ﻣﺘﻔﺎﻋﻼ ﺑﺴﺒﺐ اﻟﺮﻏﺒـﺔ ﰲ ﺗﻜﻮﻳﻦ ﻫﺬا اﻟﻜﺮﺑﻮن راﺑﻄﺔ ﻛﻴﻤ ﻴﺎﺋﻴﺔ أﺧﺮى وﺗﺤﻴﻴــﺪ ﺷــﺤﻨﺘﻪ ا ﻮﺟﺒــﺔ ﻳﻀــﻴﻒ ذرة اﻟﻜﺮﺑﻮن اﻹﺿﺎﻓﻴﺔ إﱃ ﺟﺰيء ﻛﺒـ ﺑﺸـﻜﻞ ﻣﺘﺰاﻳﺪ واﻟـﺬي ﻋـﲆ ﻣـﺪى ﻣﻼﻳـ اﻟﺴـﻨ وأﻋﺪاد ﻻ ﺗﺤﴡ ﻣﻦ اﻟﺘ ﻔﺎﻋﻼت ﻣـﻊ ا ﺰﻳـﺪ ﻣﻦ اﻟﻔﻮﺗﻮﻧﺎت واﻟﺠﺰﻳﺌﺎت اﻷﺧﺮى ﻳﻤﻜﻨ ﻬـﺎ ﰲ اﻟﻨﻬﺎﻳﺔ ﺗﻜﻮﻳﻦ ﺟﺰﻳﺌﺎت أﻛﱪ وﻧﺤـﻦ اﻵن ﻗﺎدرون أﻳﻀًـﺎ ﻋـﲆ اﻛﺘﺸـﺎف ا ﺰﻳـﺪ ﻣـﻦ ا ﻮﺛﻮﻗﻴﺔ ﺑﻔﻀﻞ وﺟﻮد ﺗﻠﺴـﻜﻮب ﻟﻸﺷـﻌﺔ ﺗﺤﺖ اﻟﺤﻤﺮاء ﻣﺜﻞ ﺗﻠﺴﻜﻮب وﻳﺐ . ﺗﻔﻴﺪ اﻟﺪراﺳﺔ اﻟﺘﻲ أﺟﺮاﻫﺎ أوﻟﻴﻔﻴﻴﻪ ﺑ ﻧﻴـﻪ ﻣﻦ ا ﺮﻛﺰ اﻟﻮﻃﻨﻲ اﻟﻔﺮﻧﴘ ﻟﻠﺒﺤﺚ اﻟﻌﻠﻤـﻲ وزﻣﻼؤه ﻣﻦ ا ﻨﻈﻤﺎت اﻷوروﺑﻴﺔ واﻷﻣﺮﻳﻜﻴﺔ واﻟﻴﺎﺑﺎﻧﻴﺔ، أﻧﻪ ﺗﻢ اﻛﺘﺸﺎف ﻛﺎﺗﻴﻮن ا ﻴﺜﻴﻞ ﰲ d203-506 وﻫﻮ أﺣﺪ اﻷﻗـﺮاص اﻟﻜﻮﻛﺒﻴـﺔ اﻟﻌﺪﻳﺪة اﻟﺘﻲ ﺗﻢ ﺗﺤﺪﻳﺪﻫﺎ ﰲ ﺳـﺪﻳﻢ اﻟﺠﺒـﺎر ﻋﲆ ﺑﻌﺪ 1350 ﺳـﻨﺔ ﺿـﻮﺋﻴﺔ ﻣـﺎ ﻛـﺎن ﰲ اﻟﺴﺎﺑﻖ ﻣﺠﺮد ﻣﻨﻄﻘﺔ ﻟﺘﺸﻜﻞ اﻟﻨﺠﻮم ﻣـﻦ اﻟﺴـﺪﻳﻢ اﻟـﺬري واﻟﺠﺰ ﻳﺌـﻲ ﺗـﻢ اﻛﺘﺸـﺎﻓﻪ