Free Astronomy Magazine September-October 2024

tronomers by yielding insights into the physics and dynamics of stellar evolution in binary systems. “In1975HMSgewentfrombeing a nondescript star to something all astronomers in the field were look- ingat,andatsomepointthatflurry of activity slowed down,” said Ravi Sankrit of the Space Telescope Sci- ence Institute (STScI) in Baltimore.In 2021, Steven Goldman of STScI,Sankrit and collaborators used in-struments on Hubble and SOFIA tosee what had changed with HM Sgein the last 30 years at wavelengthsof light from the infrared to the ul- traviolet (UV). The2021ultravioletdatafromHub- ble showed a strong emission line of highly ionized magnesium that wasnotpresentinearlierpublished spectra from 1990. Its presence showsthattheestimatedtempera- ture of the white dwarf and accre- tiondiskincreasedfromlessthan 400,000degreesFahrenheitin1989 togreaterthan450,000degrees Fahrenheitnow.Thehighlyionized magnesiumlineisoneofmanyseen intheUVspectrum,whichanalyzed together will reveal the energetics ofthesystem,andhowithaschanged in the last three decades. “When I first saw the new data,” Sankrit said, “I went – ‘wow this is what Hubble UV spectroscopy can do!’ – I mean it’s spectacular, really spectacular.” With data from NASA’s flying tele- scope SOFIA, which retired in 2022, the team was able to detect the water, gas, and dust flowing in and around the system. Infrared spec- tral data shows that the giant star, which produces copious amounts of dust, returned to its normal behav- ior within only a couple years of the explosion, but also that it has dimmed in recent years, which is another puzzle to be explained. With SOFIA astronomers were able to see water moving at around 18 miles per second, which they sus- pectisthespeedofthesizzlingac- cretion disk around the white dwarf. The bridge of gas connect- ing the giant star to the white dwarf must presently span about 2 billion miles. The team has also been workingwith the AAVSO (American Associ- ation of Variable Star Observers), to collaborate with amateur as- tronomers from around the world who help keep telescopic eyes onHM Sge; their continued monitor-ing reveals changes that haven’t been seen since its outburst 40years ago. “Symbiotic stars like HM Sge arerare in our galaxy, and witnessing a nova- like explosion is even rarer. This unique event is a treasure for astrophysicists spanning decades,” saidGoldman.     ﻣﺠﻠﺔ FreeAstronomy ﺎﻟﻌﺮ ﺔ 50 ﺻـﻮرة ﻣـﻦ ﺗﻠﺴـ ﻮبﻫﺎﺑـﻞ ــــﺎﻓﻠﻲ اﻟﻔﻀــــﺎﺋﻲ ﻟﻠــــﻨ ﻢ اﻟﺘ Mira HM Sge اﻟﺬ ﻘﻊ ﻋﻠـــــــــــــﻰ ﻌـــــــــــــﺪ 3400 ﺳـــــــــــــﻨﺔ ـﺔ ﺿﻮﺋ ﺔ ﻓﻲ ﻮﻛ اﻟﺴـﻬﻢ ـــــﻮ و ﺘ ن ﻣـــــﻦ ﻋﻤـــــﻼق أ ﻤـــــﺮ وﻗـــــــــــــــــﺰم أﺑـــــــــــــــــ ﺾﻣﺮاﻓـــــــــــــــــﻖ واﻟﻨ ﻤـــــــــــــــﺎن ـــــــــــــــ ﺎن ﻗﺮ ﻣـــــــــــــــﻦ ﻟﺎ ﻤ ﻌﻀــــــــــﻬ ﺪرﺟــــــــــﺔ اﻧــــــــــﮫ ﻻ ﻟ ﻤﻜﻦ ﺘﻠﺴ ﻮب ﻫﺎﺑـﻞ ـﺔ رؤ ــــــــﻢ ﺸــــــــ ﻞ ﻣﻨﻔﺼــــــــﻞ ــــــــﻞ ﻧ ﺗﻔ ﺾ اﻟﻤـﺎدة ﻣـﻦ اﻟﻌﻤـﻼق اﻷ ﻤــــﺮوﺗ ﻘــــﻊ ﻋﻠــــﻰ اﻟﻘـــــﺰم اﻷﺑــــ ﺾ ﻣﻤــــﺎ ﻳﺠﻌﻠــــﮫ ﻻﻣﻌـــــﺎً ــــــــﺔ ﻟﻠﻐﺎ . ﻟﻘــــــــﺪ اﻧﻔﺠــــــــﺮ ﻫــــــــﺬا اﻟﻨﻈﺎم ﻷول ﻣﺮة ﻓﻲ ﺷ ﻞ ﻣﺴﺘﻌﺮﻓﻲﻋﺎم 1975 . وﺗــﺪل اﻟﺮ ـــﺎح اﻟﻀــ ﺎﺑ ﺔ ﻋﻠـــﻰ وﺟﻮد ـﺔ اﻟﺮ ﺎح اﻟﻨ ﻤ ﻳ ﻠـﻎ و ﻋـــﺮض اﻟﺴـــﺪ ﻢ ﺣـــﻮاﻟﻲ رـــﻊ . ﺳﻨﺔﺿﻮﺋ ﺔ [NASA, ESA, Ravi Sankrit(STScI),Steven Goldman (STScI) − Joseph DePasquale (STScI)] - ﺳﺒﺘﻤﺒﺮ ﺃﻛﺘﻮﺑﺮ 2 0 2 4 ﺗﺒﻬـﺮ ﺗـﺪﻓﻘﺎت ا ـﺎدة ﻫـﺬه ﺑــ اﻟﻨﺠـﻮم ا ﺼﺎﺣﺒﺔ ﻋﻠﻤﺎء اﻟﻔﻠﻚ ﻣـﻦ ﺧـﻼل ﺗﻘـﺪﻳﻢ ﻧﻈﺮة ﺛﺎﻗﺒﺔ ﻟﻔﻴﺰﻳﺎء ودﻳﻨﺎﻣﻴﻜﻴـﺎت ﺗﻄـﻮر اﻟﻨﺠﻮم ﰲ اﻷﻧﻈﻤﺔ اﻟﺜﻨﺎﺋﻴﺔ . ﻗ ـﺎل راﰲ ﺳ ـﺎﻧﻜﺮﻳﺖ ﻣــﻦ ﻣﻌﻬ ـﺪ ﻋﻠ ـﻮم اﻟﺘﻠﺴﻜﻮب اﻟﻔﻀﺎﺋﻲ ﰲ ﺑـﺎﻟﺘﻴﻤﻮر " : ﰲ ﻋـﺎم 1975 ﺗﺤﻮل HM Sge ﻣﻦ ﻧﺠـﻢ إﱃ ﻋـﺎدي ﳾء ﻛﺎن ﺟﻤﻴﻊ ﻋﻠﻤﺎء اﻟﻔﻠﻚ ﰲ ﻫﺬا ا ﺠﺎل ﻳﻨﻈﺮو و ن إﻟﻴﻪ ﻟﻜﻦ ﰲ ﻣﺮﺣﻠﺔ ﻣﺎ ﺗﺒﺎﻃـﺄت ﻣﻮﺟﺔ اﻟﻨﺸﺎ . ط ﻋﺎم 2021 اﺳﺘﺨﺪم ﺳﺘﻴﻔﻦ ﺟﻮﻟـﺪﻣﺎن ﻣـﻦ ﻣﻌﻬـﺪ ﻋﻠـﻮم اﻟﺘﻠﺴـﻜﻮب اﻟﻔﻀﺎﺋﻲ وﺳﻨﻜﺮﻳﺖ وﻣﻌﺎوﻧﻮه اﻷﺟﻬﺰة ﻋﲆ ﺗﻠﺴﻜﻮب ﻫﺎﺑـﻞ وﻣﺮﺻـﺪ ﺻـﻮﻓﻴﺎ ﻌﺮﻓـﺔ اﻟﺘﻐــ ات ﰲ اﻟﻨﻈــﺎم HM Sgein ﺧــﻼل اﻟﺜﻼ ﺛ ﻋﺎﻣ ﺎً ا ﺎﺿﻴﺔ ﻋﻨﺪ اﻷﻃﻮال ا ﻮﺟﻴـﺔ ﻟﻠﻀﻮء ﻣﻦ اﻷﺷﻌﺔ ﺗﺤﺖ اﻟﺤﻤﺮاء إﱃ اﻷﺷﻌﺔ ﻓ ﻮق اﻟﺒﻨﻔﺴﺠﻴﺔ . أﻇﻬﺮت ﺑﻴﺎﻧﺎت اﻷﺷـﻌﺔ ﻓـﻮق اﻟﺒﻨﻔﺴـﺠﻴﺔ ﻟﻌﺎم 2021 ﻣﻦ ﺗﻠﺴﻜﻮب ﻫﺎﺑﻞ ﺧﻂ اﻧﺒﻌﺎث ﻗﻮي ﻟﻠﻤﻐﻨﻴﺴـﻴﻮم ﻋـﺎﱄ اﻟﺘـﺄﻳﻦ ﻟـﻢ ﻳﻜـﻦ اً ﻣﻮﺟﻮد ﰲ اﻷﻃﻴﺎف ا ﻨﺸﻮرة ﻣﺴـﺒﻘ ﺎً ﻣـﻦ ﻋﺎم ١٩٩٠ . ﻋــﺎم 1990 ﺣﻴـﺚ أن وﺟﻮدﻫـ ﺎ ﻳﻈﻬـﺮ أن درﺟﺔ اﻟﺤﺮارة ا ﻘﺪرة ﻟﻠﻘﺰم اﻷﺑﻴﺾوﻗﺮص اﻟﺘﻨﺎﻣﻲ زادت ﻣﻦ أﻗﻞ ﻣﻦ 400,000 درﺟـﺔ ﻓﻬﺮﻧﻬﺎﻳــﺖ ﰲ ﻋــﺎم 1989 إﱃ أﻛﺜــﺮ ﻣــﻦ 450,000 درﺟﺔ ﻓﻬﺮﻧﻬﺎﻳﺖ اﻵن . إن ﺧﻂ ا ﻐﻨﻴﺴﻴﻮم ﻋﺎﱄ اﻟﺘﺄﻳﻦ ﻫـﻮ واﺣـﺪ ﻣﻦ اﻟﻌﺪﻳﺪ ﻣـﻦ اﻟﻌﻨـﺎﴏ اﻟﺘـﻲ رﺻـﺪت ﰲ ﻃﻴ ـﻒ اﻷﺷـﻌﺔ ﻓ ـﻮق اﻟﺒﻨﻔﺴـﺠﻴﺔ وﻋﻨ ـﺪ ﺗﺤﻠﻴﻠ ﻬﺎ ﺳﻮف ﺗﻜﺸﻒ ﻋـﻦ ﻃﺎﻗـﺔ اﻟﻨﻈـﺎم اﻟﺘﻲ ﺗﻐ ت ﰲ اﻟﻌﻘﻮد اﻟﺜﻼﺛﺔ ا ﺎﺿﻴﺔ . ﻗـﺎل ﺳـﺎﻧﻜﺮﻳﺖ " : ﻋﻨـﺪﻣﺎ رأﻳـﺖ اﻟﺒﻴﺎﻧـﺎت اﻟﺠﺪﻳﺪة ﻷول ﻣﺮة ﻗﻠﺖ راﺋﻊ ﻫﺬا ﻣﺎ ﻳﻤﻜـﻦ أن ﻳﻔﻌﻠﻪ اﻟﺘﺤﻠﻴﻞ اﻟﻄﻴﻔـﻲ ﻟﻸﺷـﻌﺔ ﻓـﻮق اﻟﺒﻨﻔﺴﺠﻴ ﺔ ﺑﻮاﺳﻄﺔ ﺗﻠﺴـﻜﻮب إ ﻫﺎﺑـﻞ ﻧـﻪ ﻣﺬﻫﻞ ﺣﻘ ".ﺎً ﺗُﻈﻬﺮ اﻟﺒﻴﺎﻧـﺎت اﻟﻄﻴﻔﻴـﺔ ﺑﺎﻷﺷـ ﻌﺔ ﺗﺤـﺖ اﻟﺤﻤـﺮاء أن اﻟــﻨﺠﻢ اﻟﻌﻤـﻼق اﻟـﺬي ﻳﻨـﺘﺞ ﻛﻤﻴﺎت وﻓ ة ﻣﻦ اﻟﻐﺒـﺎر ﻋـﺎد إﱃ ﺳـﻠﻮﻛﻪ اﻟﻄﺒﻴﻌـ ﻲ ﰲ ﻏﻀـﻮن ﻋـﺎﻣ ﻓﻘ ـﻂ ﻣــﻦ ﻧﺸﺎﻃﻪ وﻟﻜﻨﻪ أﺻـﺒﺢ ﰲ ا ﺧﺎﻓﺘـﺎً ﻟﺴـﻨﻮات اﻷﺧ ة وﻫﺬا ﻟﻐﺰ آﺧﺮ ﻳﺠﺐ ﺗﻔﺴ ه . ﺑﺎﺳﺘﺨﺪام ﻣﺮﺻـﺪ ﺻـﻮﻓﻴﺎ ﺗﻤﻜـﻦ ﻋﻠﻤـﺎء اﻟﻔﻠﻚ ﻣﻦ رؤﻳﺔ ا ﺎء ﻳﺘﺤﺮك ﺑﴪـﻋﺔ ﺣـﻮاﱄ ﺑﺎﺳﺘﺨﺪام ﻣﺮﺻـﺪ ﺻـﻮﻓﻴﺎ ﺗﻤﻜـﻦ ﻋﻠﻤـﺎء اﻟﻔﻠﻚ ﻣﻦ رؤﻳﺔ ا ﺎء ﻳﺘﺤﺮك ﺑ ـ ﴪﻋﺔ ﺣـﻮاﱄ 18 ﻣﻴﻼً ﰲ اﻟﺜﺎﻧﻴﺔ وﻫﻲﴎﻋﺔ ﻳﺸـﺘﺒﻬﻮن ﰲ أﻧﻬﺎ ﴎﻋﺔ اﻟﻘﺮص اﻟﱰاﻛﻤﻲ ا ﻮﺟﻮد ﺣـﻮل اﻟﻘﺰم اﻷﺑﻴﺾ . ـﺟإن ﴪ اﻟﻐﺎز اﻟﺬي ﻳﺮﺑﻂ اﻟﻨﺠﻢ اﻟﻌﻤـﻼق ﺑﺎﻟﻘﺰم اﻷﺑﻴﺾﺣ ﺎﻟﻴ ﺎ ﻳﺠﺐ أن ﻳﺒﻠـﻎ ﻃﻮﻟـﻪ ﺣﻮاﱄ 2 ﻣﻠﻴﺎر ﻣﻴﻞ . ﻳﻌﻤﻞ اﻟﻔﺮﻳﻖ أﻳﻀﺎً ﻣﻊ اﻟﺮاﺑﻄﺔ اﻷ ﻣﺮﻳﻜﻴـﺔ ﻟﺮاﺻﺪي اﻟﻨﺠﻮم ا ﺘﻐ ة ﻟﻠﺘﻌﺎون ﻣﻊ ﻋﻠﻤﺎء واﻟ ﻓﻠﻚ ﻬﻮاة ﻣﻦ أﻧﺤﺎء اﻟﻌﺎﻟﻢ ﻟﻠﻤﺴـﺎﻋﺪة ﰲ إﺑﻘـﺎء ﻋﻴـﻮن اﻟﺘﻠﺴـﻜﻮﺑ ﺎت ﻋـﲆ HM Sge ﻟ ﺘﻜﺸﻒ ﻣﺮاﻗﺒﺘﻬﻢ ا ﺴﺘﻤﺮة ﻋﻦ ﺗﻐﻴ ات ﻟﻢ ﻧﺸﻬﺪﻫﺎ ﻣﻨﺬ اﻧﻔﺠﺎره ﻗﺒﻞ 40 .ﺎً ﻋﺎﻣ إن اﻟﻨﺠﻮم اﻟﺘﻜﺎﻓﻠﻴﺔ ﻣﺜـﻞ ﻧﻈـﺎم HM Sge ﺗﻌﺘﱪ ﻧﺎدرة ﰲ ﻣﺠﺮﺗﻨﺎ درب اﻟﺘﺒﺎﻧﺔ ﻛﻤـﺎ أن ﻣﺸﺎﻫﺪة اﻧﻔﺠﺎر ﺷﺒﻴﻪ ﺑﺎ ﺴﺘﻌﺮ أﻣـﺮ ﻫـﻮ أﻛﺜﺮ ﻧﺪرة . ﻗﺎل ﺟﻮﻟﺪﻣﺎن :” ﻳﻌﺪ ﻫﺬا اﻟﺤـﺪث اﻟﻜـﻮﻧﻲ اﻟﻔﺮﻳﺪ ﺑﻤﺜﺎﺑﺔ ﻛﻨﺰ ﻟﻌﻠﻤﺎء اﻟﻔﻴﺰﻳﺎ ء اﻟﻔﻠﻜﻴﺔ ﻋﲆ ﻣﺪى ﻋﻘﻮد ﻣﻦ اﻟﺰﻣﻦ .