Free Astronomy Magazine September-October 2025 ARABIC VERSION

All models that explain Type Ia su- pernovae begin with a white dwarfin a pair of stars. If it orbits close enough to the other star in this pair, thedwarfcanstealmaterialfromits partner.Inthemostestablishedthe- ory behind Type Ia supernovae, the white dwarf accumulates matter from its companion until it reachesa critical mass, at which point it un- dergoes a single explosion. How- ever,recentstudieshavehintedthat at least some Type Ia supernovae could be better explained by a dou- ble explosion triggered before the star reached this critical mass. Now, astronomers have captured a new image that proves their hunch wasright:atleastsomeTypeIasu- pernovae explode through a ‘dou- ble-detonation’ mechanism instead. Inthisalternativemodel,thewhite dwarfformsablanketofstolenhe- lium around itself, which can be- comeunstableandignite.Thisfirst explosiongeneratesashockwave thattravelsaroundthewhitedwarf andinwards,triggeringasecond detonationinthecoreofthestar— ultimately creating the supernova. Untilnow,therehadbeennoclear, visualevidenceofawhitedwarfun- dergoing a double detonation. Re- cently,astronomershavepredicted that this process would create a dis- tinctivepatternorfingerprintinthe supernova’sstill-glowingremains, visible long after the initial explo- sion. Research suggests that rem- nants of such a supernova wouldcontain two separate shells of cal- cium. Astronomers have now found this fingerprintinasupernova’sremains. IvoSeitenzahl,wholedtheobserva- tionsandwasatGermany’sHeidel- bergInstituteforTheoreticalStudies whenthestudywasconducted,says these results show “a clear indica- tionthatwhitedwarfscanexplode well before they reach the famous Chandrasekharmasslimit,andthat SEPTEMBER-OCTOBER2025 ﻣﺠﻠﺔ FreeAstronomy ﺎﻟﻌﺮ ﺔ 9 ﺗﻈﻬﺮ ﻫﺬﻩ اﻟﺼﻮرة اﻟ ﻤﻠﺘﻘﻄﺔ ﺎﺳﺘﺨﺪام اﻟﺘﻠﺴ ﻮب اﻟ اً ﺟﺪ ﻜﺒ اﻟﺘﺎﺑﻊ ﻟﻠﻤﺮﺻـﺪ اﻷوروﺑـﻲ اﻟــﺠﻨﻮﺑﻲ ـﺎ ﻘﺎ اﻟ اﻷ ﻤﺴـــﺘﻌﺮ ﻋﻈـــﻢ اﻟﻤﺴـــﻤﻰ SNR 0509-67.5 ـــﺎ اﻟﻤﺘﻮﺳـــﻌﺔ ﻟـــﻨ ﻢ اﻧﻔﺠـــﺮﻗﺒـــﻞ ﻣﺌـــﺎت ﻫـــﺬﻩ ﻫـــﻲ اﻟ ﻘﺎ اﻟﺴـﻨ ﺎﻧﻔﺠــﺎر ﻣـﺰدوج وﻫــﻮ أول دﻟﻴـﻞ ﻓﻮﺗــﻮ ﻏﺮاﻓﻲﻋﻠــﻰ أن اﻟﻨﺠــﻮم ﻤﻜـﻦ أن ﺗﻤـﻮت ﺎﻧﻔﺠــﺎر ﻦ . اﻟﺘُﻘﻄــﺖ اﻟﺒ ﺎﻧـــﺎت ﺎﺳـــﺘﺨﺪام ﺟﻬـــﺎز اﻟﻤﺴﺘﻜﺸـــﻒ اﻟﻄ ﻔـــﻲﻣﺘﻌــــﺪد اﻟﻮﺣـــﺪات ( ﻣـــﻮس) ﻓـــﻲ اﻟﺘﻠﺴـــ ﻮب اﻟ . اً ﺟــــﺪ ﻜﺒـــ ( ﻣـﻮس) ﺴـﻤﺢ ﻟﻌﻠﻤـﺎء اﻟﻔﻠـﻚ ﺑﺮﺳـﻢﺧﺮ ﻄـﺔ ﻟﺘﻮ ـﺔ اﻟﻤﺨﺘﻠﻔـﺔ ز ـﻊ اﻟﻌﻨﺎﺻـﺮ اﻟﻜ ﻤ ﺎﺋ ــﺄﻟﻮان اﻟﻤﻌﺮوﺿـﺔ ﻫﻨـﺎ . ﺔ ﻣﺨﺘﻠﻔ ﻈﻬﺮ اﻟ ﺎﻟﺴﻴﻮم ﺎﻟﻠﻮن اﻷزرق وﻫﻮ ﻣﺮ ﻣﺘﺤﺪﺗﻲ اﻟﻤﺮﻛﺰ ﺐ ﻓﻲﻃ ﻘﺘ . ﺗﺸـ اﻟﻄ ﻘﺘـﺎن إﻟـﻰ أن اﻟﻨ ﻢ اﻟﻤ ﺖ اﻵن اﻧﻔﺠﺮ ﺎﻧﻔﺠﺎرﻣﺰدوج . ﻈﻬﺮاﻟﻬ ﺪروﺟ ) أﻟﻔﺎ ﻫ ﺪروﺟ ( ﺎﻟﻠﻮن اﻟ ﻘﺎﻟﻲ . [ESO/P. Das et al. Background stars (Hubble): K. Noll et al.] ﺗﺒﺪأ ﺟﻤﻴﻊ اﻟﻨﻤﺎذج اﻟﺘﻲ ﺗ ـ ﴩح ا ﺴـﺘﻌﺮات اﻟﻌﻈﻤﻰ ﻣﻦ اﻟﻨﻮع Ia ﺑﻘﺰم أﺑﻴﺾﰲ زوج ﻣﻦ اﻟﻨﺠﻮم . إذا دار ﻋ ﲆ ﻣﻘﺮﺑﺔ ﻛﺎ ﻓﻴﺔ ﻣﻦ اﻟـﻨﺠﻢ اﻵﺧﺮ ﰲ ﻫﺬا اﻟﺰوج ﻳﻤﻜﻦ ﻟﻠﻘﺰم ﴎﻗﺔ ا ـﻮاد ﻣﻦ ﴍﻳﻜﻪ . ﰲ أﻛﺜﺮ اﻟﻨﻈﺮﻳﺎت رﺳـﻮﺧ ﺎ وراء ا ﺴﺘﻌﺮات اﻟﻌﻈﻤﻰ ﻣﻦ اﻟﻨﻮع Ia ﻳﺮاﻛﻢ اﻟﻘﺰم اﻷﺑﻴﺾ ا ﺎدة ﻣﻦ رﻓﻴﻘﻪ ﺣﺘﻰ ﻳﺼﻞ إﱃ ﻛﺘﻠـﺔ ﺣﺮﺟﺔ، وﻋﻨﺪ ﻫﺬه اﻟﻨ ﻘﻄﺔ ﻳﺘﻌﺮض ﻻﻧﻔﺠـﺎر . واﺣﺪ وﻣﻊ ذﻟﻚ أ ﺤﺖ اﻟﺪراﺳﺎت اﻟﺤﺪﻳﺜـ ﺔ إﱃ أﻧﻪ ﻳﻤﻜﻦ ﺗﻔﺴ ﺑﻌﺾ ا ﺴﺘﻌﺮات اﻟﻌﻈﻤـﻰ ﻣﻦ اﻟﻨﻮع Ia ﻋﲆ اﻷﻗﻞ ﺑﺸﻜﻞ أﻓﻀﻞ ﺑﺎﻧﻔﺠﺎر ﻣﺰدوج ﺣﺪث ﻗﺒـﻞ وﺻـﻮل اﻟـﻨﺠﻢ إﱃ ﻫـﺬه اﻟﻜﺘﻠﺔ اﻟﺤﺮﺟﺔ . واﻵن اﻟﺘﻘﻂ ﻋﻠﻤﺎء اﻟﻔﻠﻚ ﺻﻮرة ﺟﺪﻳﺪة ﺗﺜﺒﺖ : ﺻﺤﺔ ﺣﺪﺳﻬﻢ ﺑﻌﺾ ا ﺴـﺘﻌﺮات اﻟﻌﻈﻤـﻰ ﻣﻦ اﻟﻨﻮع Ia ﻋﲆ اﻷﻗﻞ ﺗﻨﻔﺠﺮ ﻣﻦ ﺧﻼل آﻟﻴﺔ " اﻻﻧﻔﺠﺎر ا ﺰدوج ." ﰲ ﻫﺬا اﻟﻨﻤﻮذج اﻟﺒـﺪﻳﻞ، ﻳُﺸﻜّﻞ اﻟﻘﺰم اﻷﺑـﻴﺾ ﺣـﻮل ﻧﻔﺴـﻪ ﻃﺒﻘـﺔً رﻗﻴﻘﺔً ﻣـﻦ اﻟﻬﻴﻠﻴـﻮم ا ـ واﻟ ﴪوق ـ ﺘـﻲ ﻗـﺪ ﺗﺼﺒﺢ ﻏـ ﻣﺴـﺘﻘﺮة وﺗﺸـﺘﻌﻞ ﻳ. ﻮﻟـﺪ ﻫـﺬا اﻻﻧﻔﺠﺎر اﻷول ﻣﻮﺟﺔً ﺻـﺪﻣﻴﺔً ﺗﻨ ﺘﻘـﻞ ﺣـﻮل اﻟﻘﺰم اﻷﺑﻴﺾ وإﱃ داﺧﻠـﻪ ﺤﻔﱢ ـ ﻣ ﺰة اﻧﻔﺠـﺎر اً ﺎً ﺛﺎﻧﻴ ﰲ ﻗﻠﺐ اﻟﻨﺠﻢ، ﻣﻜﻮﻧﺔ ﻟﻨﻬﺎﻳﺔ ا ﰲ ا ﺴﺘﻌﺮ اﻷﻋﻈﻢ . ﺣﺘﻰ اﻵن ﻟﻢ ﻳﻜﻦ ﻫﻨﺎك دﻟﻴﻞٌ ﻣﺮﺋـﻲ واﺿﺢ ﻋﲆ ﺣـﺪوث اﻧﻔﺠـﺎر ﻣـﺰدوج ﻟﻘـﺰم أﺑﻴﺾ . ﻣﺆﺧﺮاً ﺗﻮﻗّﻊ ﻋﻠﻤﺎء اﻟﻔﻠـﻚ أن ﺗُﺸـﻜّﻞ ﻫﺬه اﻟﻌﻤﻠﻴﺔ ﻧﻤﻄًﺎ أو ﺑﺼﻤﺔ ﻣﻤﻴّﺰة ﰲ ﺑﻘﺎﻳـﺎ ا ﺴﺘﻌﺮ اﻷﻋﻈﻢ اﻟﺘﻲ ﻻ ﺗﺰال ﻣﺘﻮﻫﺠﺔ واﻟﺘـﻲ ﺳﺘﺒﻘﻰ ﻣﺮﺋﻴﺔً ﻟﻔﱰة ﻃﻮﻳﻠـﺔ ﺑﻌـﺪ اﻻﻧﻔﺠـﺎر اﻷول . ﺗُﺸ اﻷﺑ ﺤﺎث إﱃ أن ﺑﻘﺎﻳﺎ ﻫﺬا ا ﺴﺘﻌﺮ اﻷﻋﻈﻢ ﺳﺘﺤﺘﻮي ﻋﲆ ﻃﺒﻘﺘ ﻣﻨﻔﺼﻠﺘ ﻣﻦ اﻟﻜﺎﻟﺴﻴﻮم، ﻣﻤﺎ ﻳـﻮﻓﺮ دﻟـﻴﻼً ﺣﺎﺳـﻤًﺎ ﻋـﲆ اﻻﻧﻔﺠﺎر ا ﺰدوج وﻳﻜﺸﻒ ﻋﻦ ﺗﻔﺎﺻﻴﻞ ﻏـ ﻣﺴﺒﻮﻗﺔ ﻟﺘﻠﻚ اﻟﻈﺎﻫﺮة اﻟﻜﻮﻧﻴﺔ اﻟﻨﺎدرة . ﻟ ﻘﺪ وﺟﺪ ﻋﻠﻤﺎء اﻟﻔﻠﻚ اﻵن ﻫـﺬه اﻟﺒﺼـﻤﺔ ﰲ ﺑﻘﺎﻳﺎ ا ﺴﺘﻌﺮ اﻷﻋﻈﻢ . ﻳﻘﻮل إﻳﻔﻮ ﺳﻴﺘﻴﻨﺰ ال اﻟﺬي ﻗﺎد ﻋﻤﻠﻴﺎت اﻟﺮﺻﺪ وﻛﺎن ﰲ ﻣﻌﻬﺪ ﻫﺎﻳﺪﻟﱪغ ﻟﻠﺪراﺳﺎت اﻟﻨ ﻈﺮﻳـﺔ ﺑﺄ ﺎﻧﻴﺎ وﻗﺖ إﺟﺮاء اﻟﺪراﺳﺔ ": إن ﻫﺬه اﻟﻨﺘﺎﺋﺞ ﺗﻈﻬﺮ ﻣﺆﴍ اً ﺎً واﺿﺤ ﻋﲆ أن اﻷﻗﺰام اﻟﺒﻴﻀﺎء ﻳﻤﻜﻦ أن ﺗﻨﻔﺠﺮ ﻗﺒﻞ وﻗﺖ ﻃﻮﻳﻞ ﻣﻦ وﺻ ﻮﻟﻬﺎ إﱃ ﺣـﺪ ﺗﺸﺎﻧﺪراﺳـﻴﺨﺎر اﻟﺸـﻬ وأن آﻟﻴ ـﺔ اﻻﻧﻔﺠﺎر ا ﺰدوج ﺗﺤﺪث ﺑﺎﻟﻔﻌﻞ ﰲ اﻟﻄﺒﻴﻌـﺔ ﻣﻤﺎ ﻳﻐ ﻓﻬﻤﻨﺎ ﻻﻧﻔﺠﺎرات اﻟﻨﺠﻮم ". ﺳﺒﺘﻤﺒﺮ - ﺃﻛﺘﻮﺑﺮ 2 0 2 5