Free Astronomy Magazine September-October 2023 ARABIC VERSION

A ALMA digs deeper into the mystery of planet formation by ALMAObservatory Nicolás Lira n international research team used the Atacama Large Millimeter/submillime- ter Array (ALMA) to observe disks around 19 protostars with a very high resolution to search for the ear- liest signs of planet formation. This survey, called “Early Planet Forma- tion in Embedded Disks (eDisk)” and led by Nagayoshi Ohashi at Acade- mia Sinica Institute of Astronomy and Astrophysics (ASIAA, Taiwan), was motivated by the recent find- ings that planet formation may be well-underway in the more-evolved protoplanetary disks that have been studied in detail with ALMA, but until now there had been no system- atic study to search for signs of planet formation in younger proto- stellar systems. The origins of our solar system and extrasolar planetary systems is one of the most important themes in modern astronomy. Our Sun formed about 4.6 billion years ago and all Sun-like stars from through a similar process. As part of this process, a disk forms around the newborn star and within these disks planets will form. These protoplanetary disks are ex- pected to only last a few million years, meaning that a forming plan- etary system only has this amount of time to finish its formation. How- ever, it is still not clear just how rap- idly planet formation begins within their disks. Recent ALMA observations have re- vealed that many protoplanetary disks have substructures such as gaps and rings. This is strong evidence that planets are forming and sweep- ing up material from the disk. On the other hand, many proto-plane- SEPTEMBER-OCTOBER 2023 ﻣﺠﻠﺔ FreeAstronomy ﺎﻟﻌﺮ ﺔ 47 " أﻟﻤﺎ " ﺘﻌﻤﻖ ﻓﻲﻟﻐﺰ ﺗ ﻮﻳﻦ اﻟ ﻮ ﻛﺐا : ﻘﻠﻢ ﻧﻴ ﻮﻻس ﻟ ا - ﻣﺮﺻﺪ أﻟﻤﺎ ا ﺪم ــــ ﺳﺘﺨ ﻓﺮﻳـﻖ ﺑﺤـﺚ دوﱄ ﻣﺼـﻔﻮﻓﺔ ﻣﺮﺻﺪ أﺗﻜﺎﻣـ ﺎ ا ﻠﻴﻤـﱰي / ﺗﺤـﺖ ا ﻠﻴﻤـﱰي اﻟﻜﺒ ( أ ﺎ) ﺮاﻗﺒﺔ اﻷﻗﺮاص ﺣﻮل 19 ﻧﺠﻤـﺎً أوﻟﻴﺎً ﺑﺪﻗﺔ ﻋﺎﻟﻴﺔ ﺟﺪ اً ﻟﻠﺒﺤﺚ ﻋـﻦ اﻟﻌﻼﻣـﺎت اﻷوﱃ ﻟﺘﻜﻮﻳﻦ اﻟﻜﻮا . ﻛﺐ ﻛﺎن اﻟﺪاﻓﻊ وراء ﻫﺬه اﻟﺪراﺳﺔ اﻟﺘﻲ أﻃﻠﻖ ﻋﻠﻴﻬﺎ " ﺗﻜﻮﻳﻦ اﻟﻜﻮﻛـﺐ ا ﺒﻜﺮ ﰲ اﻷﻗﺮاص ا ﺪﻣﺠﺔ إي ) ( دﻳﺴﻚ واﻟﺘﻲ ﻗﺎدﻫﺎ ﻧﺎﺟﺎﻳﻮﳾ أوﻫﺎﳾ ﻣﻦ ﻣﻌﻬﺪ أﻛﺎدﻳﻤﻴﺎ ﺳﻴﻨﻴﻜﺎ ﻟﻌﻠـﻢ اﻟﻔﻠـﻚ واﻟﻔﻴﺰﻳـﺎء اﻟﻔﻠﻜﻴـﺔ ﰲ ﺗﺎﻳﻮان ﻫﻮ اﻟﻨﺘﺎﺋﺞ اﻷﺧ ة اﻟﺘﻲ ﺗﺸـ إﱃ أن ﺗﻜﻮﻳﻦ اﻟﻜﻮﻛﺐ ﻗﺪ ﻳﻜﻮن ﻗﻴﺪ اﻟﺘﻨﻔﻴﺬ ﺑﺸﻜﻞ . ﺟﻴﺪ ﰲ اﻷﻗﺮاص اﻟﻜﻮﻛﺒﻴـﺔ اﻷوﻟﻴـﺔ اﻷﻛﺜـﺮ ﺗﻄـﻮرًا واﻟﺘـﻲ ﺗﻤـﺖ دراﺳـﺘﻬﺎ ﺑﺎﻟﺘﻔﺼـﻴﻞ ﺗﻄـﻮر اً واﻟﺘـﻲ ﺗﻤـﺖ دراﺳـﺘﻬﺎ ﺑﺎﻟﺘﻔﺼـﻴﻞ ﺑﺎﺳﺘﺨﺪام ﻣﺮﺻﺪ أ ﺎ ﻟﻜﻦ ﺣﺘﻰ اﻵن ﻟﻢ ﺗﻜـﻦ ﻫﻨﺎك دراﺳﺔ ﻣﻨﻬﺠﻴﺔ ﻟﻠﺒﺤﺚ ﻋـﻦ ﻋﻼﻣـﺎت ﺗﻜﻮﻳﻦ اﻟﻜﻮاﻛﺐ ﰲ اﻷﻧﻈﻤﺔ اﻟﻨﺠﻤﻴﺔ اﻷوﻟﻴـﺔ اﻷﺣﺪث . ﺗﻌــﺪ أﺻ ـﻮل ﻧﻈﺎﻣﻨ ـﺎ اﻟﺸﻤﴘــ وأﻧﻈﻤــﺔ اﻟﻜﻮاﻛﺐ اﻟﻨﺠﻤﻴﺔ واﺣﺪة ﻣﻦ أﻫﻢ ا ﻮﺿﻮﻋﺎت ﰲ ﻋﻠﻢ اﻟﻔﻠﻚ اﻟﺤﺪﻳﺚ . ﻟﻘﺪ ﺗﺸﻜﻠﺖ اﻟﺸﻤﺲ ﻣﻨﺬ ﺣـﻮاﱄ 4.6 ﻣﻠﻴـﺎر ﺳﻨﺔ وﺟﻤﻴﻊ اﻟﻨﺠﻮم اﻟﺸﺒﻴﻬﺔ ﺑﺎﻟﺸﻤﺲ ﻣﻦ ﺧـﻼل ﻋﻤﻠ ﻴـﺔ ﻣﻤﺎﺛﻠـﺔ . وﻛﺠـﺰء ﻣـﻦ ﻫـﺬه اﻟﻌﻤﻠﻴﺔ ﻳﺘﺸﻜﻞ ﻗﺮص ﺣـﻮل اﻟـﻨﺠﻢ اﻟﻮﻟﻴـﺪ ــــــ وداﺧﻞ ﻫﺬه اﻷﻗﺮاصﺳﺘﺘﺸﻜﻞ اﻟﻜﻮاﻛﺐ . ﻛﺸﻔﺖ ﻋﻤﻠﻴﺎت اﻟ ﺮﺻـﺪ اﻷﺧـ ة ﺑﻮاﺳـﻄﺔ ﻣﺮﺻﺪ أ ﺎ أن اﻟﻌﺪﻳﺪ ﻣـﻦ أﻗـﺮاص اﻟﻜﻮاﻛـﺐ اﻷوﻟﻴﺔ ﺗﺤﺘﻮي ﻋـﲆ ﻫﻴﺎﻛـﻞ أﺳﺎﺳـﻴﺔ ﻣﺜـﻞ اﻟﻔﺠﻮات واﻟﺤﻠﻘﺎت وﻫﺬا دﻟﻴﻞ ﻗﻮي ﻋـﲆ أن اﻟﻜﻮاﻛﺐ ﺗﺸﻜﻞ وﺗﺠﺮف ا ﻮاد ﻣـﻦ اﻟﻘـﺮص وﻣﻦ ﻧﺎﺣﻴﺔ أﺧﺮى ﺗُﻈﻬﺮ اﻟﻌﺪﻳﺪ ﻣﻦ اﻷﻗﺮاص اﻟ ﻜﻮﻛﺒﻴﺔ اﻷوﻟﻴﺔ ﻣﺜﻞ ﻫـﺬه اﻟﻌﻼﻣـﺎت ﻣﻤـﺎ ﻳﺸ إﱃ أن ﻫﻨﺎك ﻋﻤﻠﻴـﺔ ﺗﻜـﻮﻳﻦ ا ﻠﻜﻮ ﻟ ﻛـﺐ ﺟﺎرﻳـﺔ ﺑﺎﻟﻔﻌـﻞ أو ﻋـﲆ وﺷـﻚ اﻻﻧﺘﻬـﺎء ﰲ اﻷﻧﻈﻤـﺔ اﻟﺘـﻲ ﻧﺸـ إﻟﻴﻬـﺎ ﻋـﺎد ةً ﺑﺎﺳـﻢ " أﻗﺮاص اﻟﻜﻮاﻛﺐ اﻷوﻟﻴﺔ ". ﻌ 8 - ﺳﺒﺘﻤﺒﺮ ﺃﻛﺘﻮﺑﺮ 2 0 2 3 اﺳﺘﺨﺪم