Free Astronomy Magazine March-April 2025 ARABIC VERSION

One of the telescopes that can ob- serve them is the Atacama Millime- ter/submillimeter Array (ALMA). This array of 66 antennas in north- ern Chile is specifically designed to detect long wavelength radiation from cold astronomical sources, like exocomet belts. Using ALMA, the Hawaiian Submil- limeter Array (SMA), and archival data,ateamledbyLucaMatrà,an associateprofessorattheUniversity of Dublin, has embarked on a mis- sion to image as many exocomet beltsaspossibleinallstages,from newly formed to very mature. The survey, Resolved ALMA and SMA Observations of Nearby Stars (REA- SONS), is the largest of its kind to date.Thesurveycontainsimagesof 74beltsaround“nearby”planetary systems located within 500 light- yearsofEarth.Theresults,published in AstronomyandAstrophysics ,al- ﻣﺠﻠﺔ FreeAstronomy ﺎﻟﻌﺮ ﺔ 24 أﺣﺪ اﻟﺘﻠﺴﻜﻮﺑﺎت اﻟﻘﺎدرة ﻋﲆ رﺻﺪﻫﺎ ﻫـﻮ ﻣﺮﺻﺪ ﻣﺼﻔﻮﻓﺔ أ ﺗﺎﻛﺎﻣـﺎ ا ﻠﻴﻤﱰﻳـﺔ دون / ا ﻠﻴﻤﱰ ( أ ﺎ)ﻳﺔ ﺗﻢ ﺗﺼﻤﻴﻢ ﻫﺬه ا ﺼـﻔﻮﻓﺔ ا ﻜﻮﻧﺔ ﻣـﻦ 66 ﻫﻮاﺋﻴـﺎَ ﰲ ﺷـﻤﺎل ﺗﺸـﻴﲇ ﺎً ﺧﺼﻴﺼ ﻟﻠﻜﺸﻒ ﻋﻦ اﻹﺷﻌﺎع ﻃﻮﻳﻞ ا ﻮﺟﺔ ﻣﻦ ا ﺼﺎدر اﻟﻔﻠﻜﻴﺔ اﻟﺒـﺎردة ﻣﺜـﻞ أﺣﺰﻣـﺔ ا ﺬﻧﺒﺎت اﻟ ﻨﺠﻤﻴﺔ . ﺑﺎﺳﺘﺨﺪام ﻣﺼﻔﻮﻓﺔ ﻣﺮﺻﺪ أ ﺎ وﻣﺼـﻔﻮﻓﺔ ﻫــﺎواي ا ﻠﻴﻤﱰﻳــﺔ ) ( ﺳــﻤﺎ واﻟﺒﻴﺎﻧــﺎت اﻷرﺷﻴﻔﻴﺔ ﴍع ﻓﺮﻳﻖ ﺑﻘﻴﺎدة ﻟﻮﻛـﺎ ﻣـﺎﺗﺮا ـــ أﺳﺘﺎذ ﻣﺸـﺎرك ﰲ ﺟﺎﻣﻌـﺔ دﺑﻠـﻦ ﰲ ﻣﻬﻤـﺔ ﻟﺘﺼـﻮﻳﺮ أﻛـﱪ ﻋـﺪد ﻣﻤﻜـﻦ ﻣـﻦ أﺣﺰﻣـﺔ ا ﺬﻧﺒﺎت اﻟ ﻨﺠﻤﻴـﺔ ﰲ ﺟﻤﻴـﻊ ا ﺮاﺣـﻞ ﻣـﻦ ا ﺘﻜﻮﻧﺔ ﺣﺪﻳﺜًﺎ إﱃ اﻟﻨﺎﺿﺠﺔ ﺟﺪ . اً إن ا ﺴـﺢ اﻟﺬي أﻃﻠـﻖ ﻋﻠﻴـﻪ اﺳـﻢ ارﺻـﺎد " و ( ﺎ أ ـ) ( ﺳﻤﺎ ) ﻟﻠﻨﺠﻮم اﻟﻘﺮﻳﺒـﺔ ) " رﻳـﺰوﻧﺲ ﻫـﻮ ( اﻷﻛﱪ ﻣﻦ ﻧﻮﻋﻪ ﺣﺘﻰ اﻵن وﻳﺤﺘﻮي ا ﺴـﺢ ﻋﲆ ﺻﻮر ﻟـ 74 ﺎَ ﺣﺰاﻣ ﺣﻮل أﻧﻈﻤﺔ ﻛﻮﻛﺒﻴﺔ " ﻗﺮﻳﺒﺔ " ﺗﻘـﻊ ﺿـﻤﻦ ﻣﺴـﺎﻓﺔ 500 ﺳـﻨﺔ ﺿﻮﺋﻴﺔ ﻣﻦ اﻷرض وﺗﺘﺤﺪى اﻟﻨﺘـﺎﺋﺞ اﻟﺘـﻲ ـــ ﻧُﴩت ﰲ ﻣﺠﻠﺔ اﻟﻔﻠـﻚ واﻟﻔﻴﺰﻳـﺎء اﻟﻔﻠﻜﻴـﺔ أﻓﻜﺎر ﻋﻠ ﻤـﺎء اﻟﻔﻠـﻚ ﺣـﻮل ﻫـﺬه اﻟﻬﻴﺎﻛـﻞ ﺑﺎﻟﻔﻌﻞ . ﻟﻴﺴﺖ ﻛﻞ اﻷﺣﺰﻣﺔ ﻣﺘﺴﺎوﻳﺔ . ﻓﻘﺪ ﻛﺸﻒ ﻣﺴﺢ رﻳﺰوﻧﺲ ) ( أن أﺣﺰﻣﺔ ا ﺬﻧﺒﺎت اﻟﻨﺠﻤﻴﺔ ﺗﺄﺗﻲ ﰲ ﺟﻤﻴﻊ اﻷﺷﻜﺎل واﻷﺣﺠـﺎم واﻷﻋﻤﺎر ﻟﻜﻦ اﻟﻌﻠﻤﺎء ﺑﺪأوا ﰲ رؤﻳـﺔ ﺑﻌـﺾ اﻷﻧﻤﺎط داﺧﻞ ﻫﺬا اﻟﺘﻨﻮع . أﺣﺪ ﻫﺬه اﻷﻧﻤﺎط ﻫﻮ أن اﻷ ﺣﺰﻣﺔ أﻛﱪ ﺑﺸـﻜﻞ ﻣﻠﺤـﻮظ ﻣـﻦ ا ﺘﻮﻗﻊ واﻷﺣﺰ ﻣﺔ اﻷﺻﻐﺮ أﻗﺮب إﱃ ﻧﺠﻤﻬـﺎ ا ﻀﻴﻒ ﻣﻤﺎ ﻳﺠﻌﻠﻬﺎ أﻛﺜـﺮ ﺳـﺨﻮﻧﺔ وأﻛﺜـﺮ ــــ ﺗًﻈﻬﺮ أﺣﺰﻣﺔ اﻟﻤـﺬﻧ ﺎت ـﺔ اﻟﻨ ﻤ اﻟــ 74 ﺗـﻢ ﺗﺼـﻮﻳﺮﻫﺎ اﻟـ ﺑﻮاﺳــــﻄﺔ ﻣﺴــــﺢ ر ــــﺰوﻧﺲ ا ﻟﺘــــﺎﺑﻊ ﻟـــــ ﻤﺮﺻﺪ أﻟﻤــــﺎ أﺣﺰﻣــــﺔ ﻣــــﻦ ﻤﻴﻊ اﻷﺷ ﺎل واﻷﺣﺠﺎم واﻷﻋﻤﺎر . [ALMA (ESO/NAOJ/NRAO)/SMA/L.Matràetal.]