Free Astronomy Magazine May-June 2025 ARABIC VERSION

for these novae can vary from as lit- tle as one year to many decades. Less than a dozen recurrent novae havebeenobservedwithinour Milky Way Galaxy, while far moreare extragalactic, meaning located outside of the Milky Way. Studying extragalacticnovaehelpsbuildas- tronomers’ understanding of how differentenvironmentsaffectnova eruptions. The first recurrent extragalactic novatobeobservedwasLMC1968- 12a (LMC68), located in the Large Magellanic Cloud — a satellite galaxyoftheMilkyWay.Thisnova has a recurrent timescale of about four years — the third-shortest of any nova — and consists of a white dwarf and a companion red sub- giant (a star much larger than the Sun).Itwasdiscoveredin1968and its eruptions have been observed fairly regularly since 1990. MAY-JUNE2025 ﻣﺠﻠﺔ FreeAstronomy ﺎﻟﻌﺮ ﺔ 37 ﻟﻘﺪ رُ ﺻﺪ أﻗـﻞ ﻣـﻦ اﺛﻨـ ـﻋـ ﺎ اً ﴩ ﻣﺴـﺘﻌﺮ اً ﻣﺘﻜﺮر داﺧﻞ ﻣﺠﺮﺗﻨـﺎ درب اﻟﺘﺒ ﺎﻧـﺔ ﺑﻴﻨﻤـﺎ ﻳﻮﺟﺪ ﻋﺪد أﻛﱪ ﺑﻜﺜ ﺧﺎرج ا ﺠﺮة . ﺗُﺴﺎﻋﺪ دراﺳﺔ ا ﺴﺘﻌﺮات ﺧﺎر ج ا ﺠﺮة ﻋﲆ ﺑﻨﺎء ﻓﻬﻢ ﻋﻠﻤﺎء اﻟﻔﻠﻚ ﻟﻜﻴﻔﻴﺔ ﺗﺄﺛ اﻟﺒﻴﺌﺎت ا ﺨﺘﻠﻔﺔ ﻋﲆ ﺛﻮرات ا ﺴﺘﻌﺮات . ﻟﻘـﺪ ﻛـﺎن أول ﻣﺴﺘﻌﺮ ﺧﺎرج ﻣﺠﺮي ﻣﺘﻜﺮر ﻳﺮﺻﺪ ﻫﻮ LMC1968-12a (LMC68) اﻟﻮاﻗﻊ ﺿﻤﻦ ﺳﺤﺎﺑﺔ ﻣﺎﺟﻼن اﻟﻜﱪى وﻫﻲ ﻣ ﺗﺎﺑﻌﺔ ﺠﺮة ﺠـﺮة درب اﻟﺘﺒﺎﻧـﺔ . ﻳﺒﻠـﻎ ﻣﻘﻴـﺎس ﻫـﺬا ا ﺴﺘﻌﺮ ا ﺘﻜﺮر ﺣﻮاﱄ أرﺑـﻊ ﺳـﻨﻮات وﻫـﻮ ﺛﺎﻟﺚ أﻗ ﻣ ﴫـ ﻘﻴﺎس زﻣﻨﻲ ﺑ ا ﺴـﺘﻌﺮات اﻷﺧﺮى وﻳﺘﻜﻮن ﻣﻦ ﻗـﺰم أﺑـﻴﺾ وﻋﻤـﻼق أﺣﻤﺮ ﻣﺮاﻓﻖ وﻫﻮ ﻧﺠـﻢ أﻛـﱪ ﺑﻜﺜـ ﻣـﻦ ـــــ اﻟﺸﻤﺲ ﻣﻦ . اﻛﺘُﺸﻒ ﻋﺎم 1968 وﻣﺎ زاﻟـﺖ ﺛﻮراﺗ ﻪ ﺗُـﺮﺻَﺪ ﺑﺸﻜﻞ دوري وﻣﻨﺘﻈﻢ ﺛﻮراﺗﻪ ﺑﺎﻧﺘﻈﺎم وذﻟﻚ ﺗﺤﺪﻳﺪ اً ﻋﺎم 1990 ﺑﺎﺳﺘﺨﺪا م اﻟﻌﺪﻳﺪ ﻣﻦ اﻟ ﺘﻠﺴﻜﻮﺑﺎت اﻷرﺿﻴﺔ اﻟو ﻔﻀﺎﺋﻴﺔ ا ﺘﺨﺼﺼــﺔ ﺘﺎﺑﻌــﺔ ﺗﻐ اﺗــﻪ اﻟﻄﻴﻔﻴــﺔ واﻟﻀﻮﺋﻴﺔ وﻓﻬﻢ آﻟﻴﺔ ﻧﺸﺎﻃﻪ ا ﺘﻜـﺮر ﻋـﱪ اﻟﻌﻘﻮد ا ﺎﺿﻴﺔ . ﺼﻮر ﻫﺬا اﻟﺮﺳﻢ اﻟﺘﺨ ﻠﻲ ﺛﻮراﻧ ﻧ ﻤ ﺎً ﺎً اً ﺟﺪ ﺪ اﻟ ﺧﺎرج ﻳ. ﻤﺠـﺮة ﺤـﺪث ا ﻧﻔﺠـﺎر اﻟ ﻤﺴـﺘﻌﺮ ـﺔ ﻓـﻲ أﻧﻈﻤـﺔ اﻟﻨﺠـﻮم اﻟﺜﻨﺎﺋ ـﺚ ﺴـﺤﺐ اﻟﻘـﺰم اﻷﺑـ ﺾ ﺣ - ـﺎ اﻟﻜﺜ ﻔـﺔ اﻟ ﻘﺎ ﻟﻠﻨ ﻢ اﻟﻤ ﺖ - ﺎﺳﺘﻤﺮارا ـﻢ ﻣﺮاﻓـﻖ ﻗﺮ ـﺐ ﻟﻤﻮاد اﻟﻨ ﻤ ﺔ ﻣﻦ ﻧ وﻣـﻊ وﺻـﻮل اﻟﻐـﻼف اﻟـ ـ ـ ﺠﻮي اﻟـ ﺨﺎرﺟﻲ ﻟﻠـﻨ ﻢ اﻟﻤﺮاﻓـﻖ إﻟـﻰﺳـﻄﺢ اﻟﻘـﺰم اﻷﺑـ ﺾ و ﺗﺮ ﻔـﻊ درﺟـﺔ ﺣﺮارﮫ ﻤﺎ ﻜﻔﻲﻹﺣﺪاث ﺛﻮران . رُﺻـﺪ اﻟ ت ﻤﻴـﻊ ﻤﺴـﺘﻌﺮات اﻟﻤﻜﺘﺸـﻔﺔ ـﺎً ﺗﻘﺮ اﻵن ﻣـﺮة واﺣـﺪة ﻓﻘـﻂوﻟﻜـﻦ ﻧـﺎدر ﺣـ اً ﻣـﺎ ﻟـﻮﺣﻆ ﺛﻮراﻧﻬـﺎ أﻛـ ﻣـﻦ ﻣـﺮة وﺗﺼـﻨﻒ ﻋﻠﻰ أﻧﻬﺎ ﻣﺴﺘﻌﺮات ﻣﺘﻜﺮرة ﻤﻜﻦ أن ﺗ ﺛﻮراتﻫﺬﻩ اﻟ اوح اﻟﻔ ة ﺑ ﻤﺴﺘﻌﺮات ﻣﻦﺳﻨﺔ إﻟﻰ ﻋﺪة ﻋﻘﻮد . [InternationalGeminiObservatory/NOIRLab/NSF/AURA/M.Garlick,M.Zamani] ﻣﺎﻳﻮ - ﻳﻮﻧﻴﻮ 2 0 2 5