Free Astronomy Magazine July-August 2024 ARABIC VERSION

34 Clash of stars solves stellar mystery by ESO − Bárbara Ferreira hen doing back- ground reading, I was struck by how special this system seemed,” says Abigail Frost, an astronomer at ESO in Chile and lead author of the study published in Science . The sys- tem, HD 148937, is located about 3800 light-years away from Earth in the direction of the Norma constel- lation. It is made up of two stars much more massive than the Sun and surrounded by a beautiful neb- ula, a cloud of gas and dust. “A neb- ula surrounding two massive stars is a rarity, and it really made us feel like something cool had to have happened in this system. When looking at the data, the coolness only increased.” “After a detailed analysis, we could determine that the more massive star appears much younger than its companion, which doesn’t make any sense since they should have formed at the same time!” Frost says. The age difference — one star appears to be at least 1.5 million years younger than the other — suggests something must have reju- venated the more massive star. An- other piece of the puzzle is the neb- ula surrounding the stars, known as NGC 6164/6165. It is 7500 years old, hundreds of times younger than both stars. The nebula also shows very high amounts of nitrogen, car- bon and oxygen. This is surprising as these elements are normally ex- pected deep inside a star, not out- side; it is as if some violent event had set them free. To unravel the mystery, the team as- sembled nine years’ worth of data from the PIONIER and GRAVITY in- struments, both on ESO’s Very Large Telescope Interferometer (VLTI), lo- cated in Chile’s Atacama Desert. They also used archival data from the FEROS instrument at ESO’s La Silla Observatory. “We think this system had at least three stars originally; two of them had to be close together at one point in the orbit whilst another star was much more distant,” ex- plains Hugues Sana, a professor at KU Leuven in Belgium and the prin- cipal investigator of the observa- tions. “The two inner stars merge d ﺻﺮاع اﻟﻨﺠﻮم ﻳﺤﻞ اﻟﻠﻐﺰاﻟﻨ ﻤﻲ : ﻘﻠﻢ ﺎر ﺮا ﻓ ﺮا – اﻟﻤﺮﺻﺪ اﻷوروﺑﻲ اﻟـﺠﻨﻮﺑﻲ ﻋﻨـﺪﻣﺎ ﻛﻨــﺖ أﻗــﻮم ﺑــﺎﻟﻘﺮاءة أذﻫﻠﺘﻨــﻲ اﻟﻄﺮﻳﻘﺔ اﻟﺘﻲ ﺑﺪا ﻫﺬا اﻟﻨﻈﺎم ﺑﻬﺎ " ﻣﻤﻴﺰاً ﺗﻘﻮل أﺑﻴﺠﻴﻞ ﻓﺮوﺳﺖ ﻋﺎ ﺔ اﻟﻔﻠﻚ ﰲ ا ﺮﺻﺪ اﻷوروﺑ ـﻲ ﰲ ﺗﺸ ـﻴﲇ وا ﺆﻟﻔ ـﺔ اﻟﺮﺋﻴﺴ ـﻴﺔ ﻟﻠﺪراﺳﺔ ا ﻨﺸﻮرة ﰲ ﻣﺠﻠﺔ . ﺳﺎﻳﻨﺲ ﻳﺒﻌﺪ اﻟﻨﻈـﺎم HD 148937 ﻣﺴـﺎﻓﺔ ﺗﺒﻠـﻎ ﺣﻮاﱄ 3800 ﺳـﻨﺔ ﺿـﻮﺋﻴﺔ ﻣـﻦ اﻷرض ﰲ اﺗﺠﺎه ﻛﻮﻛﺒﺔ ﻧﻮرﻣﺎ وﻳﺘﻜـﻮن ﻣـﻦ ﻧﺠﻤـ أﻛﱪ ﺑﻜﺜـ ﻣـﻦ ﻛﺘﻠـﺔ اﻟﺸـﻤﺲ وﻣﺤـﺎط ﺑﺴﺪﻳﻢ ﺟﻤﻴﻞ ﻋﺒﺎرة ﻋﻦ ﺳﺤﺎﺑﺔ ﻣﻦ اﻟﻐـﺎز . " واﻟﻐﺒﺎر إن وﺟﻮد ﺳ ﺪﻳﻢ ﻳﺤـﻴﻂ ﺑﻨﺠﻤـ ﺿﺨﻤ أﻣﺮ ﻧﺎدر وﻗ ﺪ ﺟﻌﻠﻨﺎ ﻧﺸﻌﺮ ﺣﻘًﺎ أن ﺎً راﺋﻌ ﺷﻴﺌﺎً ﻻ ﺑﺪ أن ﻳﺤـﺪث ﰲ ﻫـﺬا اﻟﻨﻈـﺎم وﻋﻨﺪ اﻟﻨﻈﺮ إﱃ اﻟﺒﻴﺎﻧﺎت ازدادت ". روﻋﺔ ﺗ ﻘﻮل ﻓﺮوﺳﺖ ": ﺑﻌﺪ ﺗﺤﻠﻴﻞ ﻣﻔﺼﻞ ﻳﻤﻜﻨﻨﺎ ﺗﺤﺪﻳﺪ أن اﻟﻨﺠﻢ اﻷﻛ ﱪ ﻛﺘﻠﺔ ﻳﺒﺪو أﺻﻐﺮ ﺳﻨﺎً ﺑﻜﺜ ﻣﻦ رﻓﻴﻘﻪ وﻫﺬا ﻟﻴﺲ ﻟـﻪ أي ﻣﻌﻨـﻰ ﻷﻧﻪ ﻛﺎن ﻳﻨﺒﻐﻲ أن ﻳﻜﻮﻧﺎ ﻗﺪ ﺗﺸﻜﻼ ﰲ ﻧﻔﺲ اﻟﻮﻗﺖ "! . ﻳﺸ ﻓﺎرق اﻟﺴﻦ - ﻳﺒـﺪو أن أﺣـﺪ اﻟﻨﺠـﻮم أﺻﻐﺮ ﻣﻦ اﻵﺧﺮ ﺑﻤﺎ ﻻ ﻳﻘﻞ ﻋﻦ 1.5 ﻣﻠﻴـﻮن -ﺳﻨﺔ إﱃ أن ﺷـﻴﺌًﺎ ﻣـﺎ ﻗـﺪ أدى إﱃ ﺗﺠﺪﻳـﺪ ﺷﺒﺎب اﻟﻨﺠﻢ اﻷﻛﺜﺮ ﺿﺨﺎﻣ أﺧﺮ ﺟﺰء . ﺔ ﻣـﻦ اﻟﻠﻐﺰ ﻫ ﻮ اﻟﺴﺪﻳﻢ ا ﺤﻴﻂ ﺑﺎﻟﻨﺠﻮم وا ﻌﺮوف ﺑﺎﺳـﻢ NGC 6164/6165 وﻳﺒﻠـﻎ ﻋﻤـﺮه 7500 ﺔﺳﻨ ﻋﻤﺮه 7500 ﺳﻨﺔ ـــــ 34 7500 ﺔ و ﺳﻨ ﻫﻮ أﺻﻐﺮ ﻣـﻦ ﻛـﻼ اﻟﻨﺠﻤـ ﺑﻤﺌﺎت ا ﺮات . ﻛﺬﻟﻚ ﻳُﻈﻬـﺮ اﻟ ﺴـﺪﻳﻢ أﻳﻀـﺎ ﻛﻤﻴﺎت ﻋﺎﻟﻴﺔ ﺟﺪ ا ﻣﻦ اﻟﻨﻴﱰوﺟ واﻟﻜﺮﺑﻮن واﻷﻛﺴﺠ . إن ﻫﺬا أﻣﺮ ﻣﺜ ﻟﻠﺪﻫﺸـﺔ إذ ﻣـﻦ ا ﺘﻮﻗـﻊ ﻋﺎدة أن ﺗﻜـﻮن ﻫـﺬه اﻟﻌﻨـﺎﴏ ﰲ أﻋﻤـﺎق اﻟﻨﺠﻢ وﻟﻴﺲﺧﺎرﺟﻪ ، ﻳﺒﺪو اﻷﻣﺮ ﻛﻤﺎ ﻟـﻮ أن ﺣ ﺪﺛﺎ ﻋﻨﻴﻔﺎ ﻗﺪ ﻗﺎم ﺑﺈﻃﻼﻗﻬﺎ . ﻟﻜﺸﻒ اﻟﻠﻐﺰ ﻗﺎم اﻟﻔﺮﻳﻖ ﺑﺘﺠﻤﻴـﻊ ﺑﻴﺎﻧـﺎت ﺗﻜﻔﻲ ﻟﺘﺴﻊ ﺳﻨﻮات ﻣﻦ أ ﺑـﺎوﻧ " دوات و " " " ﻏﺮاﻓﻴﺘﻲ وﻛﻼﻫﻤﺎ ﻣﻘﻴﺎس ﺗﺪاﺧﻞ ﻣﺘﺼﻠﺔ ﺑ ﺎﻟﺘﻠﺴﻜﻮب اﻟﻜﺒـ ﺟـﺪ ا اﻟﺘـﺎﺑﻊ ﻟﻠﻤﺮﺻـﺪ اﻷوروﺑــﻲ اﻟﺠﻨــﻮﺑﻲ ا ﻮﺟــﻮد ﰲ ﺻ ـﺤﺮاء أﺗﺎﻛﺎﻣﺎ ﰲ ﺗﺸﻴﲇ . ﻟﻘﺪ اﺳﺘﺨﺪﻣﻮا أﻳﻀ ﺎ اﻟﺒﻴﺎﻧﺎت اﻷرﺷﻴﻔﻴﺔ ﻣﻦ ﻣﻄﻴــﺎف " ﻓ ـ وس " ا ﻮﺟـﻮد ﰲ ﻣﺮﺻـﺪ ﻻﺳﻴﻼ اﻟﺘﺎﺑﻊ ﻟﻠﻤﺮﺻﺪ اﻷوروﺑـﻲ اﻟﺠﻨـﻮﺑﻲ وﻳﻌﺘﻘﺪو ن ﺑﺄن ﻫﺬا اﻟﻨﻈﺎم ﻛﺎن ﻳﺤﺘﻮي ﻋﲆ ﺛﻼﺛﺔ ﻧﺠﻮم - - ﻋﲆ اﻷﻗﻞ . ﰲ اﻷﺻﻞ ﻳﻮﺿﺢ ﻫﻴﻮز ﺳﺎﻧ ﺎ اﻷﺳﺘﺎذ ﺑﺠﺎﻣﻌﺔ ﻟﻮﻓـﺎن اﻟﻜﺎﺛﻠﻮﻟﻴﻜﻴﺔ ﰲ ﺑﻠﺠﻴﻜﺎ واﻟﺒﺎﺣﺚ اﻟﺮﺋﻴ ﰲ ﺲـ ﻋﻤﻠﻴﺎ : " ت اﻟﺮﺻـﺪ ﻳﺠـﺐ أن ﻳﻜـﻮن اﺛﻨـﺎن ﻬﻤﺎ ﻣﻨ ﻗﺮﻳﺒ ﻣﻦ ﺑﻌﻀـﻬﻤﺎ اﻟـﺒﻌﺾ ﻋﻨـﺪ ﻧﻘﻄﺔ واﺣﺪة ﰲ ا ﺪار ﺑﻴﻨﻤـﺎ ﻳﻜـﻮن اﻟـﻨﺠﻢ اﻵﺧﺮ أﺑ ﻌﺪ ﺑﻜﺜ ."