Free Astronomy Magazine January-February 2024 ARABIC VERSION

49 The Crab Nebula seen in new light by Webb by NASA/ESA/CSA Abigail Major & Christine Pulliam ASA’s James Webb Space Tele- scope has gazed at the Crab Nebula, a supernova remnant located 6,500 light-years away in the constellation Taurus. Since the recording of this energetic event in 1054 CE by 11 th -century as- tronomers, the Crab Nebula has continued to draw attention and additional study as scientists seek to understand the conditions, behav- ior, and after-effects of supernovae through thorough study of the Crab, a relatively nearby example. Using Webb’s NIRCam (Near-In- frared Camera) and MIRI (Mid-In- frared Instrument), a team led by Tea Temim at Princeton University is searching for answers about the Crab Nebula’s origins. “Webb’s sensitivity and spatial reso- lution allow us to accurately deter- mine the composition of the ejected material, particularly the content of iron and nickel, which may reveal what type of explosion produced the Crab Nebula,” explained Temim. At first glance, the general shape of the supernova remnant is similar to the optical wavelength image re- leased in 2005 from NASA’s Hubble Space Telescope: In Webb’s infrared observation, a crisp, cage-like struc- ture of fluffy gaseous filaments are shown in red-orange. However, in the central regions, emission from dust grains (yellow-white and green) is mapped out by Webb for the first time. Additional aspects of the inner workings of the Crab Neb- ula become more prominent and are seen in greater detail in the in- frared light captured by Webb. In particular, Webb highlights what is known as synchrotron radiation: emission produced from charged particles, like electrons, moving around magnetic field lines at rela- tivistic speeds. The radiation ap- pears here as milky smoke-like ma- terial throughout the majority of the Crab Nebula’s interior. This feature is a product of the neb- ula’s pulsar, a rapidly rotating neu- tron star. The pulsar’s strong mag- netic field accelerates particles to extremely high speeds and causes them to emit radiation as they wind around magnetic field lines. Though emitted across the electromagnetic JANUARY-FEBRUARY 2024 ﻗﺎم ﺗﻠﺴﻜﻮب ﺟﻴﻤﺲ وﻳﺐ اﻟﻔﻀﺎﺋﻲ اﻟﺘﺎﺑﻊ ﻟﻮﻛﺎﻟﺔ اﻟﻔﻀﺎء اﻷﻣﺮﻳﻜﻴﺔ ( ﻧﺎﺳﺎ ) ﺑﺎﻟﺘﺤـﺪﻳﻖ ﰲ ﺳﺪﻳﻢ اﻟﴪ ﻃﺎن وﻫﻮ ﺑﻘﺎﻳﺎ ﻣﺴﺘﻌﺮ أﻋﻈﻢ ﻳﻘﻊ ﻋﲆ ﺑﻌﺪ 6500 ﺳﻨﺔ ﺿـﻮﺋﻴﺔ ﰲ ﻛﻮﻛﺒـﺔ اﻟﺜﻮر . ﻣﻨﺬ ﺗﺴﺠﻴﻞ ﻫﺬا اﻟﺤﺪث اﻟﻨﺸﻂ ﰲ ﻋﺎم 1054 م ﻣـﻦ ﻗﺒـﻞ ﻋﻠﻤـﺎء اﻟﻔﻠـﻚ ﰲ اﻟﻘـﺮن اﻟﺤﺎدي ﻋﴩ ، اﺳﺘﻤﺮ ﺳـﺪﻳﻢ اﻟﺴـ ـ ﺮﻃﺎن ﰲ ﺟـﺬب اﻻﻧﺘﺒـﺎه واﻟﺪراﺳـﺔ اﻹﺿـﺎﻓﻴﺔ ﺣﻴـﺚ ﻳﺴﻌﻰ اﻟﻌﻠﻤﺎء إﱃ ﻓﻬـﻢ اﻟﻈـﺮوف واﻟﺴـﻠﻮك واﻵﺛﺎر اﻟﻼﺣﻘ ﺔ ﻟﻠﻤﺴﺘﻌﺮات اﻷﻋﻈﻤﻴـﺔ ﻣـﻦ ﺧﻼل دراﺳﺔ ﺷﺎﻣﻠﺔ ﻟﺴﺪﻳﻢ اﻟﴪﻃﺎن . ﻣﺜﺎل ﻗﺮﻳﺐ ﻧﺴﺒﻴﺎ . ﺑﺎﺳـﺘﺨﺪام ﻛـﺎﻣ ا ﺗﻠﺴـﻜﻮب وﻳﺐ ﻧ ﻛﺎم ) ﻛﺎﻣ ا اﻷﺷﻌﺔ ﺗﺤﺖ اﻟﺤﻤـﺮاء اﻟﻘﺮﻳﺒﺔ ( أد) وﻣ ي اة اﻷﺷﻌﺔ ﺗﺤﺖ اﻟﺤﻤﺮاء ا ﺘﻮﺳﻄﺔ ( ﻳﺒﺤﺚ ﻓﺮﻳﻖ ﺑﻘﻴﺎدة ﺗﻲ ﺗﻴﻤـﻴﻢ ﰲ ﺟﺎﻣﻌﺔ ﺑﺮﻳﻨﺴﺘﻮن ﻋﻦ إﺟﺎﺑﺎت ﺣﻮل أﺻـﻮل ﺳﺪﻳﻢ اﻟﴪ . ﻃﺎن أوﺿﺢ ﺗﻴﻤﻴﻢ " : إن ﺣﺴﺎﺳﻴﺔ ﺗﻠﺴﻜﻮب وﻳﺐ ودﻗﺔ ا ﻜﺎن ﺗﺴﻤﺢ ﻟﻨﺎ ﺑﺘﺤﺪﻳﺪ ﺗﺮﻛﻴﺒﺔ ا ـﺎدة ا ﻘﺬوﻓﺔ ﺑﺪﻗـﺔ، وﺧﺎﺻـﺔ ﻣﺤﺘـﻮى اﻟﺤﺪﻳـﺪ واﻟﻨﻴﻜﻞ، ﻣﻤﺎ ﻗﺪ ﻳﻜﺸﻒ ﻋﻦ ﻧـﻮع ا ﻻﻧﻔﺠـﺎر اﻟﺬي أﻧﺘﺞ ﺳﺪﻳﻢ اﻟﴪـﻃﺎن ". ﻟﻠﻮﻫﻠـﺔ اﻷوﱃ ﻳﺒﺪو اﻟﺸﻜﻞ اﻟ ﻌﺎم ﻟﺒﻘﺎﻳـﺎ ا ﺴـﺘﻌﺮ اﻷﻋﻈـﻢ ﺎً ﻣﺸﺎﺑﻬ ﻟﺼﻮرة اﻟﻄﻮل ا ﻮ ﺟﻲ اﻟﻀﻮﺋﻴﺔ اﻟﺘﻲ ﺻﺪرت ﻋﺎم 2005 ﺑﻮاﺳﻄﺔ ﺗﻠﺴﻜﻮب ﻫﺎﺑﻞ ـ اﻟﻔﻀﺎﺋﻲ اﻟﺘﺎﺑﻊ ﻟﻨﺎﺳﺎ . إن اﻟﻘﺪرة ﻋﲆ دراﺳﺔ ﻛﻴﻔﻴﺔ ﺗﺸﻜﻞ اﻟﻨﺠﻮم ﻋـﲆ ﻫـﺬه ا ﺴـﺎﻓﺎت ا ﺬﻫﻠﺔ وﰲ ﻣﺠﺮة ﻣﺨﺘﻠﻔﺔ أﻣﺮ ﻣﺜ ﻟﻠﻐﺎﻳﺔ ." ﻳﻈﻬﺮ ﰲ رﺻﺪ وﻳﺐ ﻟﻸﺷﻌﺔ ﺗﺤـﺖ اﻟﺤﻤـﺮاء ﻫﻴﻜﻞ واﺿـﺢ ﻳﺸـﺒﻪ اﻟﻘﻔـﺺ ﻣﻜـﻮن ﻣـﻦ ﺧﻴﻮط ﻏﺎزﻳﺔ رﻗﻴﻘﺔ ﺑ ﺎﻟﻠﻮن اﻷﺣﻤﺮ اﻟﱪﺗﻘﺎﱄ . وﻣﻊ ذﻟـﻚ ﰲ ا ﻨـﺎﻃﻖ اﻟﻮﺳـﻄﻰ ﺗـﻢ رﺳـﻢ ﺧﺮﻳﻄـﺔ ﻟﻼﻧﺒﻌﺎﺛـﺎت ﻣـﻦ ﺣﺒﻴﺒـﺎت اﻟﻐﺒـﺎر ) اﻷﺻﻔﺮ واﻷﺑـﻴﺾ واﻷﺧـ ( ﴬـ ﻷول ﻣـﺮة . أﺻـﺒﺤﺖ ﺟﻮاﻧـﺐ إﺿـﺎﻓﻴﺔ ﻣـﻦ اﻟﻌﻤﻠﻴـﺎت اﻟﺪاﺧﻠﻴﺔ ﻟﺴﺪﻳﻢ اﻟـ ـ ﴪﻃﺎن أﻛﺜـﺮ وﺿـﻮﺣﺎ وﻋﲆ وﺟﻪ اﻟﺨﺼﻮص ﻳﺴﻠﻂ ﺗﻠﺴﻜﻮب وﻳـﺐ اﻟﻀﻮء ﻋﲆ ﻣﺎ ﻳﻌﺮف ﺑﺈﺷﻌﺎع اﻟﺴﻨﻜﺮوﺗﺮون : وﻫﻮ اﻧﺒﻌﺎث ﻳﻨﺘﺞ ﻣﻦ ﺟﺴـ ﻴﻤﺎت ﻣﺸـﺤﻮﻧﺔ ﻣﺜﻞ اﻹﻟﻜﱰوﻧﺎت ﺗﺘﺤﺮك ﺣﻮل ﺧﻄﻮط ا ﺠﺎل ا ﻐﻨﺎﻃﻴﴘ ﺑﴪﻋﺎت ﻧﺴﺒﻴﺔ . ﻳﻈﻬﺮ اﻹﺷﻌﺎع ﻫﻨﺎ ﻋﲆ ﺷﻜﻞ ﻣﺎدة ﺗﺸﺒﻪ اﻟﺪﺧﺎن ﰲ ﻣﻌﻈـﻢ أﻧ ﺤﺎء اﻟﺠﺰء اﻟﺪاﺧﲇ ﻟﺴﺪﻳﻢ اﻟﴪﻃﺎن وﻫﺬه ا ﻴﺰة ﻫﻲ ﻧﺘﺎج اﻟﻨﺠﻢ اﻟﻨﺎﺑﺾ ﻟﻠﺴﺪﻳﻢ وﻫـﻮ ﻧﺠﻢ ﻧﻴﻮﺗﺮوﻧﻲﴎﻳﻊ اﻟﺪوران . ﻳﻌﻤﻞ ا ﺠـﺎل ا ﻐﻨﺎﻃـ ﻴﴘ ا ـ ﻟﻘـﻮي ﻟﻠـﻨﺠﻢ اﻟﻨﺎﺑﺾ ﻋﲆ ﺗﴪﻳﻊ اﻟﺠﺴﻴﻤﺎت إﱃ ﴎﻋـﺎت ﻋﺎﻟﻴﺔ ﻟﻠﻐﺎﻳﺔ وﻳﺠﻌﻠﻬﺎ ﺗﺒـﺚ إﺷـﻌﺎﻋ ﺎ أﺛﻨـﺎء دوراﻧﻬﺎ ﺣﻮل ﺧﻄﻮط ا ﺠـﺎل ا ﻐﻨﺎﻃﻴـ ﴘـ ﻋ ـﲆ اﻟ ـﺮﻏﻢ ﻣ ـﻦ اﻧﺒﻌﺎﺛﻬ ـﺎ ﻋ ـﱪ اﻟﻄﻴ ـﻒ اﻟﻜﻬﺮوﻣﻐﻨﺎﻃﻴﴘ [NASA, ESA, CSA, STScI, Tea Temim (Princeton University)] " و ﺐ " ﻘﺪم ﻧﻈﺮة ﺟﺪ ﺪة ﻟ ﺴﺪ ﻢ اﻟﺴﺮﻃﺎن : ﻘﻠﻢ ﺑﻮﻟ ﺎم أﺑﻴﺠﻴﻞ ﻣﻴﺠﻮروﻛﺮﺴﺘ و ﺎﻻت اﻟ ﻔﻀﺎء ﻧﺎﺳﺎ /ﺴﺎ إ/ اﻟﻜﻨﺪ ﺔ ﻣﺠﻠﺔ FreeAstronomy ﺎﻟﻌﺮ ﺔ 49 - ﻳﻨﺎﻳﺮ ﻓﺒﺮﺍﻳﺮ 2 0 2 4