Free Astronomy Magazine May-June 2025 ARABIC VERSION

still relatively warmer and brighter and therefore easier to observe de- spite the obscuring, dense dust and gasthatcomprisestheFlameNebula in this case. NASA’sJamesWebbSpaceTelescope can pierce this dense, dusty region andseethefaintinfraredglowfrom young brown dwarfs. A team of as- tronomersusedthiscapabilitytoex- plorethelowestmasslimitofbrown dwarfs within the Flame Nebula. The result, they found, were free- floating objects roughly two to threetimesthemassofJupiter,al- thoughtheyweresensitivedownto 0.5 times the mass of Jupiter. “The goalofthisprojectwastoexplore thefundamentallow-masslimitof thestarandbrowndwarfformation process. With Webb, we’re able to probethefaintestandlowestmass objects,” said lead study author Matthew De Furio of the University of Texas at Austin. The low-mass limittheteamsoughtissetbya process called fragmentation. In this processlargemolecularclouds,from which both stars and brown dwarfs are born, break apart into smaller and smaller units, or fragments. Fragmentation is highly dependent onseveralfactorswiththebalance betweentemperature,thermalpres- 31 ﻣﺠﻠﺔ FreeAstronomy ﺎﻟﻌﺮ ﺔ ﺗﻈﻬﺮ ﺻﻮرة اﻷﺷﻌﺔ ﺗﺤﺖ اﻟ ـ ﻤﺮاء اﻟﻘﺮ ﺔ ﻟ ـ ﺠﺰء ﻣﻦﺳﺪ ﻢ اﻟﺸﻌﻠﺔ اﻟﺘﻘﻄﻬ واﻟ ﺎ ﺗﻠﺴ ﻮ بﺟ ﻤﺲ ـــﺐ اﻟﻔﻀـــﺎﺋﻲ اﻟﺘـــﺎﺑﻊ ﻟﻨﺎﺳـــﺎ و ﺛﻼﺛـــﺔ أﺟـــﺮام ﻣﻨﺨﻔﻀـــﺔ اﻟﻜﺘﻠـــﺔ ﺗﻈﻬـــﺮﻓـــﻲ اﻟﺼـــﻮراﻟﻤﺮﻓﻘـــ ﺔ ﻋﻠـــﻰ اﻟ ﻤـــ ﺗﺘﻄﻠـﺐ ﻫــﺬﻩ اﻷﺟــﺮام اﻷﻛــ ــﺔ ﺑــﺮودة ﻜﺜــ ﻣــﻦ اﻟﻨﺠـﻮم اﻷوﻟ ﺣﺴﺎﺳـ ﺔ أﺟﻬــﺰة ﺗﻠﺴــ ﻮب ــﺐ ﻟﺮﺻــﺪﻫﺎ و ﻟ ﻘـــﺪ دُرﺳـــﺖ ﻫـــﺬﻩ اﻷﺟـــﺮامﺿـــﻤﻦ ﻣﺴـــﻌﻰﻻﺳﺘﻜﺸـــﺎف اﻟـــ ـ ﺤﺪ اﻷدﻧـــﻰ ﻟﻜﺘﻠـــﺔ اﻷﻗـــﺰام ـــ اﻟ ﻨ ﺔ اﻟﻤﻮﺟـــﻮدة داﺧﻞ ﺳﺪ ﻢ اﻟ ﺸﻌﻠﺔ وﺗﻤﺜﻞ أﻟـﻮان ﺻـﻮر ﺗﻠﺴـ ﻮب ـﺔ ﻣﺤـﺪدة ﻟﻠﻀـﻮء ـﺐ أﻃـﻮاﻻً ﻣﻮﺟ و : اﻷزرق ﻤﺜـﻞ 1.5 و 1.4 ) ﻣ ﻜــﺮون ﻋــ ﻣﺮﺷــﺤﻲ F115W و F140M ( واﻷﺧﻀــﺮ ﻤﺜــﻞ 1.82 ) ﻣ ﻜــﺮون ﻋــ ﻣﺮﺷــﺢ F182M ( واﻟ ﻘـــــــﺎﻟﻲ ﻤﺜـــــــﻞ 3.6 ﻣ ﻜـــــــﺮون ) ﻋـــــــ ﻣﺮﺷـــــــﺢ F360M ( واﻷ ﻤـــــــﺮ ﻤﺜـــــــﻞ 4.3 ﻣ ﻜـــــــﺮون ) ﻋـــــــ ﻣﺮﺷـــــــﺢ F430M .( [NASA, ESA, CS , STScI, Michael Meyer (University of Michigan)] اﻟﺸﻤﺲ ﻟﻜﻦ ﰲ ﻣﺮاﺣﻠﻬﺎ اﻷوﱃ ﺗﻜﻮن ﻫـﺬه اﻷﻗﺰام أﻛﺜﺮ دﻓﺌ ﺎً و ﻌﺎﻧﺎً ﻧﺴﺒﻴﺎً ﻣﻤﺎ ﻳﺴـﻬﻞ رﺻﺪﻫﺎ ﻋﲆ اﻟـﺮﻏﻢ ﻣـﻦ اﻟ ﻋﻮاﻣـﻞ ﺤﺠـﺐ ا ﺘﻤﺜﻠﺔ ﰲ اﻟﻐﺒﺎر واﻟﻐﺎز اﻟﻜﺜﻴﻒ ا ﻜﻮﻧﻪ ﻟﻬﺬا اﻟﺴﺪﻳﻢ ﻳﺴﺘﻄﻴﻊ ﺗﻠﺴـﻜﻮب ﺟـﻴﻤﺲ وﻳـﺐ اﺧﱰاق ﻫﺬه ا ﻨﻄﻘﺔ ﻟﺮؤﻳﺔ وﻫـﺞ اﻷﺷـﻌﺔ ﺗﺤﺖ اﻟﺤﻤﺮاء اﻟﺨﺎﻓﺖ ا ﻨﺒﻌﺚ ﻣﻦ اﻷﻗـﺰام اﻟﺒﻨﻴﺔ اﻟﺸﺎﺑﺔ . وﻗﺪ اﺳﺘﻐﻞ ﻓﺮﻳﻖ ﻣﻦ ﻋﻠﻤﺎء اﻟﻔﻠﻚ ﻫﺬه اﻟﻘﺪرة ﻻﺳﺘﻜﺸﺎف اﻟﺤﺪ اﻷدﻧـﻰ ﻟﻜﺘﻠــﺔ اﻷﻗــﺰام اﻟﺒﻨﻴــﺔ ﰲ ﺳـﺪﻳﻢ اﻟﺸـﻌﻠﺔ وﺗﻮﺻـﻠﻮا إﱃ أن أدﻧـﻰ ﻛﺘﻠـﺔ ﺗـﻢ رﺻـﺪﻫﺎ ﻷﺟﺴﺎم ﻋﺎﺋﻤﺔ ﺣﺮة ﺗﱰاوح ﺑـ ﺿـﻌﻔ وﺛﻼ ﺛﺔ أﺿﻌﺎف ﻛﺘﻠﺔ ا ﺸﱰي ﺗﻘﺮﻳﺒﺎً ﺎً ﻋﻠﻤـ ﺑﺄن ﺣﺴﺎﺳﻴﺔ اﻟﺘﻠﺴـﻜﻮب ﺗﺼـﻞ إﱃ )0.5( ﻛﺘﻠﺔ ا ﺸﱰي . ﻗﺎل ﻣـﺎﺛﻴﻮ ﻓ ﻮرﻳـﻮ اﻟﺒﺎﺣـﺚ ﻴﴘﰲ ـ اﻟﺮﺋ اﻟﺪراﺳﺔ ﻣﻦ ﺟﺎﻣﻌﺔ ﺗﻜﺴﺎسﰲ أوﺳــﺘﻦ " : ﻛــﺎن ﻫــﺪف ﻫــﺬا ا ﴩــوع ـ اﻟﺮﺋ ﻴﴘﰲ ا ﻟﺪراﺳﺔ ﻣﻦ ﺟﺎﻣ ﻌﺔ ﺗﻜﺴﺎسﰲ أوﺳــﺘﻦ " : ﻛــﺎن ﻫــﺪف ﻫــﺬا ا ﴩــوع اﺳﺘﻜﺸﺎف اﻟﺤﺪ اﻷﻗـ ـ ﴡ ﻟﻠﻜﺘﻠـﺔ ﻟﻌﻤﻠﻴـﺔ ﺗﻜﻮﻳﻦ اﻟﻨﺠﻮم واﻷﻗ ﺰام اﻟﺒﻨﻴﺔ و ﺑﺎﺳـﺘﺨﺪام ﺗﻠﺴﻜﻮب وﻳﺐ ﻳُ ﻤﻜﻨﻨﺎ اﺳﺘﻜﺸﺎف اﻷﺟﺴـﺎم ذات اﻟﻜﺘﻠﺔ ﻛﺜﺎﻓﺔ و اﻷﻗﻞ ." ﻳﺴﻌﻰ اﻟﻔﺮﻳـﻖ إﱃ ﺗﺤﺪﻳﺪ ذﻟﻚ ﻣـﻦ ﺧـﻼل ﻋﻤﻠﻴـﺔ ﻣﻌﻘـﺪة ﺗﺴﻤﻰ اﻟﺘﺠﺰﺋﺔ . ﰲ ﻫﺬه اﻟﻌﻤﻠﻴﻰ ﺗﺴـﻤﻰ اﻟﺘﺠﺰﺋـﺔ ﺣﻴــﺚ ﺗﺘﻔﻜـﻚ اﻟﺴـ ﺤﺐ اﻟﺠﺰﻳﺌﻴﺔ اﻟﻜﺒ ة ﻟﻠﻐﺎﻳﺔ و ﻫﻲ ﻣـﺎدة أوﻟﻴـﺔ أﺳﺎﺳﻴﺔ ﻟﺘﺸﻜﻞ اﻟﻨﺠﻮم واﻷﻗﺰام اﻟﺒﻨ ﻴـﺔ إﱃ وﺣﺪات أو ﺷﻈﺎﻳﺎ أﺻﻐﺮ ﺗـﺪرﻳﺠﻴ ﺎً وﺗﻌﺘﻤـﺪ ﻋﻤﻠﻴﺔ اﻟﺘﺠﺰﺋﺔ ﺑﺸﻜﻞ ﻛﺒ ﻋﲆ ﻋﺪ ة ﻋﻮاﻣﻞ رﺋﻴﺴﻴﺔ أﺑﺮزﻫﺎ اﻟﺘﻮازن اﻟﺪﻗﻴﻖ ﺑـ درﺟـﺔ اﻟﺤﺮارة واﻟﻀﻐﻂ اﻟﺤﺮاري واﻟﺠﺎذﺑﻴﺔ . ﻣﺎﻳﻮ - ﻳﻮﻧﻴﻮ 2 0 2 5