Free Astronomy Magazine January-February 2025 ARABIC VERSION

A Planets can form under harsh radiation byNationalRadioAstronomyObservatory ewobservationsfromtheAt- acama Large Millimeter/sub- millimeter Array (ALMA) suggest that planet formation can occureveninharshstellarenviron- ments previously thought to be in- hospitable. An international team of astronomers used ALMA to cap- turehigh-resolutionimagesof eightprotoplanetarydisksinthe SigmaOrioniscluster,whichisirra- diatedbyintenseultravioletlight fromamassivenearbystar. To their surprise, they foundevi- dence of gaps and rings in most of the disks—structures commonly as- sociated with the formation of giant planets, like Jupiter. “We expected the high levels of ra- diation in this cluster to inhibit planet formation in the outer re- gions of these disks,” said lead author Jane Huang. “But instead, we’re seeing signs that planets may be forming at distances of tens of astronomicalunitsfromtheirstars, rtistconceptofplanetformation occuring in harsh stellar environ- ments.[NSF/AUI/NSFNRAO/S.Dagnello] similar to what we’ve observed in less harsh environments.” Previous studies had focusedon disksinregionswithlowultraviolet radiation. This new research pro- videstheALMA’shighestresolution look at disks in a more extreme environment. “These observations suggestthattheprocessesdriving JANUARY-FEBRUARY2025 ﻣﺠﻠﺔ FreeAstronomy ﺎﻟﻌﺮ ﺔ 32 اﻟ ﻮاﻛﺐ ﻤﻜﻦ أن ﺗﺘﺸ ﻞ ﺔ ﻘﺎﺳ اﻟ ﺷﻌﺎع ﻹا ﻓﻲﺑﻴﺌﺔ : ﻘﻠﻢ ﻟﻌﻠﻢ اﻟﻔﻠﻚ اﻟﺮادﻳﻮي ﺟﻮزي اﻟﻤﺮﺻﺪ اﻟﻮﻃ رﺳــﻢ ﺗﺨ ﻠـﻲ ﺗﺤــﺪث ﻓــﻲ ـﻮﻳﻦ اﻟ ﻮاﻛــﺐ اﻟـ ﻟﺘ اﻟﺒﻴﺌﺎت اﻟﻨ ﻤ ﺔ اﻟﻘﺎﺳ ﺔ . ] NSF/AUI/NSFNRAO/S.Dagnello [ ﺗﺸـ اﻷ رﺻــﺎد اﻟﺠﺪﻳـﺪة ﻣـﻦ ﻣﺼـﻔﻮﻓﺔ أﺗﺎﻛﺎﻣﺎ ا ﻠﻴﻤﱰﻳﺔ اﻟﻜﺒ ة / ﺗﺤﺖ ا ﻠﻴﻤﱰﻳـﺔ أ ﺎ) ( إﱃ أن ﺗ ﻜﻮﻳﻦ اﻟﻜﻮاﻛﺐ ﻳﻤﻜﻦ أن ﻳﺤﺪث ﺣﺘﻰ ﰲ اﻟﺒﻴﺌﺎت اﻟﻨﺠﻤﻴﺔ اﻟﻘﺎﺳﻴﺔ اﻟﺘﻲ ﻛﺎن ﻳُﻌﺘﻘﺪ ﺳﺎﺑﻘًﺎ أﻧﻬﺎ ﻏ ﻣﻀﻴﺎﻓﺔ . اﺳـﺘﺨﺪم ﻓﺮﻳـﻖ دوﱄ ﻣـﻦ ﻋﻠﻤـﺎء اﻟﻔﻠ ـﻚ ﻣﺼﻔﻮﻓﺔ أﺗﺎﻛﺎﻣﺎ ا ﻠﻴﻤﱰﻳﺔ اﻟﻜﺒ ة ﻻﻟﺘﻘﺎط ﺻﻮر ﻋﺎﻟﻴﺔ اﻟﺪﻗﺔ ﻟﺜﻤﺎﻧﻴﺔ أﻗﺮاص ﻛﻮﻛﺒ ﻴـﺔ أوﻟﻴﺔ ﰲ ﻣﺠﻤﻮﻋﺔ ﺳـﻴ ﻐ ﻤﺎ أورﻳـﻮن واﻟﺘـﻲ ﺗﺘﻌﺮض ﻟﻺﺷﻌﺎ ع ﻓﻮق اﻟﺒﻨﻔﺴـﺠﻲ ا ﻜﺜـﻒ ﻣﻦ ﻧﺠﻢ ﻗﺮﻳﺐ ﻫﺎﺋﻞ وا ﻔﺎﺟﺄة أﻧﻬﻢ وﺟﺪوا ــ دﻟﻴﻼً ﻋﲆ وﺟﻮ د ﻓﺠﻮات وﺣﻠﻘﺎت ﰲ ﻣﻌﻈـﻢ اﻷﻗ ـﺮاص وﻫــﻲ ﻫﻴﺎﻛ ـﻞ ﻣﺮﺗﺒﻄـ ﺔ ﻋـﺎدةً ﺑﺘﻜﻮﻳﻦ اﻟﻜﻮاﻛﺐ اﻟﻌﻤﻼﻗـﺔ اﻟﻐﺎزﻳـﺔ ﻣﺜـﻞ ﻛﻮﻛﺐ ا ﺸﱰي . ﻗﺎل ا ﺆﻟﻒ اﻟﺮﺋﻴﴘﺟ ﻫـﻮاﻧﺞ " : ﺗﻮﻗﻌﻨـﺎ أن ﺗﻤﻨﻊ ا ﺴﺘﻮﻳﺎت اﻟﻌﺎﻟﻴﺔ ﻣﻦ اﻹﺷـﻌﺎع ﰲ ﻫﺬه ا ﺠﻤﻮﻋﺔ ﺗﻜﻮﻳﻦ اﻟﻜ ﻮاﻛﺐ ﰲ ا ﻨـﺎﻃﻖ اﻟﺨﺎرﺟﻴﺔ ﻣﻦ ﻫﺬه اﻷﻗﺮاص وﻟﻜﻦ ﺑﺪﻻً ﻣـﻦ ذﻟﻚ، ﻧﺮى ﻋﻼﻣﺎت ﺗﺸ إﱃ أن اﻟﻜﻮاﻛﺐ ﻗـﺪ ﺗﺘﺸﻜﻞ ﻋﲆ ﻣﺴﺎﻓﺎت ـﻋـ ﴩات اﻟﻮﺣـﺪات اﻟﻔﻠﻜﻴﺔ ﻣﻦ ﻧﺠﻮﻣﻬﺎ ﻋﲆ ﻏﺮ ار ﻣﺎ رﺻـﺪﻧﺎه ــــ ﰲ ﺑﻴﺌﺎت أﻗﻞ ﻗﺴﻮ . ة ﻟﻘﺪ رﻛـﺰت اﻟﺪراﺳـﺎت اﻟﺴـﺎﺑﻘﺔ ﻋــﲆ اﻷﻗــﺮاصﰲ ا ﻨ ـﺎﻃﻖ ذات اﻹﺷﻌﺎع ﻓﻮق اﻟﺒﻨﻔﺴﺠﻲ ا ﻨﺨﻔﺾ . ﻳﻮﻓﺮ ﻫﺬا اﻟﺒﺤﺚ اﻟﺠﺪﻳﺪ ﻧﻈﺮة ﻋﺎﻟﻴﺔ اﻟﺪﻗﺔ ﻷ ﺎ ﻟﻸﻗﺮاص ﰲ ﺑﻴﺌﺔ أﻛﺜـﺮ ﺗﻄﺮﻓًـﺎ وأﺷـﺎر ﻫﻮاﻧﺞ إﱃ أن ﻫـﺬه " اﻷرﺻـﺎد ﺗﺸـ إﱃ أن اﻟﻌﻤﻠﻴﺎت اﻟﺘﻲ ﺗﻘ ﻮد إﱃ ﺗﻜﻮﻳﻦ ﻛﻮاﻛﺐ ﻗﻮﻳﺔ ﻟﻠﻐﺎﻳﺔ ـــ - ﻳﻨﺎﻳﺮ ﻓﺒﺮﺍﻳﺮ 2 0 2 5