Free Astronomy Magazine July-August 2026 ARABIC VERSION

41 Young stars are surrounded by a vast shroud of gas and dust called anenvelope.Gravitypullsthisma- terial inward, feeding both the growingstarandthediskaroundit. But the infalling gas moves differ- ently than the disk — more slowly and chaotically — and the point at which one becomes the other had never been clearly observed. Earlier theoretical models assumed the switch was sharp, al- most instantaneous. The newstudyshowsitisn’t. Usingnumericalsimula- tions with the FEOSAD code,theteamtracked how a collapsing cloud coreevolvesintoastar- disk system — andfound that the transi- tion unfolds gradually across a finite region, leavingatell-talesigna- ture: a characteristic “jump” in the distribu- tion of specific angular momentum, a measure of how gas rotates as a function of its distance from the star. “The existence of END- TRANZ naturally results from the redistribution ofmassandangularmo- mentum during the for- mation of disks around youngstars.Thisprocess ultimately governs how infalling material from theenvelope,whichro- the Keplerian speed, spreads out to form the disk and gradually settles into ordered Keplerian rotation,” explained Das. To test whether ENDTRANZ exists in nature, the team turned to L1527 IRS, a young protostar about 450 light-years away in the Taurus mo- lecular cloud. Using data from the ALMA Large Program eDisk (Em- beddedDisksinPlanetFormation), they found exactly the same angu- lar momentum signature that the simulations had predicted — span- ning a zone roughly 16 astronomi- calunitswide,orabout16timesthe distance from Earth to the Sun. “This ENDTRANZ tracer essentially manifests from the gradual transi- tionintherotationalvelocity,which offers a diagnostic framework for understandingthephysicalproc- essesatplaythatdrivethediskevo- lution,” saidShantanuBasu,Interim Director of the Canadian Institute forTheoreticalAstrophysicsandco- author of the study. ALMA’s extraordinary resolution wasessentialtomakingthisdetec- tion possible, resolving the structure atthepreciseinterfacebetweenthe envelopeandthedisk—aregime thathadpreviously been beyond reach. “A careful inspection andcomparisonof the radial dependence ofspecificangular momentumbetween the observational da- ta and the simulations helpedidentifythe evidence of END- TRANZinL1527IRS,” said Nagayoshi Oha- shi, principal investi- gator of the ALMA eDisk Large Program and co-author of the study. The discovery estab- lishes ENDTRANZ as a fundamental feature ofhowstarsandplan- etary systems assem- ble — and opens the door to searching for the same signature in other young systems across the galaxy. “In many ways, we be- lievethisisjustthebe- tatesmoreslowlythan ginning!” Dassaid.    JULY-AUGUST2026 ﻣﺠﻠﺔ FreeAstronomy ﺎﻟﻌﺮ ﺔ 41 ﺗﺤﺎط اﻟﻨﺠﻮم اﻟﻔﺘﻴ ﺔ ﺑﻐﻼف واﺳﻊ ﻣﻦ اﻟﻐﺎز واﻟﻐﺒﺎر ﻳ ﻌﺮف ﺑﺎﺳﻢ اﻟﻐﻼف ا ﺤﻴﻂ وﺗﺴﺤﺐ اﻟﺠﺎذﺑﻴﺔ ﻫﺬه ا ﺎدة إﱃ اﻟﺪاﺧﻞ ﻟﺘﻐﺬي اﻟـﻨﺠﻢ ا ﺘﻨﺎﻣﻲ واﻟﻘﺮص ا ﺤـﻴﻂ ﺑـﻪ . ﻟﻜـﻦ اﻟﻐـﺎز اﻟﺴﺎﻗﻂ ﻳﺘﺤﺮك ﺑﻄ ﺮﻳﻘﺔ ﻣﺨﺘﻠﻔﺔ ﻋﻦ اﻟﻐـﺎز داﺧﻞ اﻟﻘﺮص إذ ﺗﻜﻮن ﺣﺮﻛﺘـﻪ أﺑﻄـﺄ وأ ﻛﺜـﺮ اﺿـﻄﺮاﺑ ﺎً وﻟـﻢ ﻳﻜـﻦ ﻣﻮﺿـﻊ اﻟﺘﺤـﻮل ﺑـ اﻟﺤ ﺎﻟﺘ ﻗﺪ ر ﺻﺪ ﺑﻮﺿﻮح ﻣـﻦ ﻗﺒـﻞ . ﻛﺎﻧـﺖ اﻟﻨﻤﺎذج اﻟﻨﻈﺮﻳﺔ اﻟﺴـﺎﺑﻘﺔ ﺗﻔـﱰض أن ﻫـﺬا اﻟﺘﺤﻮل ﻳﺤﺪث ﺑﺸﻜﻞ ﺣﺎد وﻓﻮري ﺗﻘﺮﻳﺒًﺎ، إﻻ ـﻜﻞ ﺣـﺎد وﻓ ـــﻮري ﺗﻘﺮﻳﺒ ـــﺎً إﻻ أن اﻟﺪراﺳﺔ اﻟﺠﺪﻳﺪة أﻇﻬﺮت أن اﻟﻮاﻗﻊ أﻛﺜـﺮ ﺗﻌﻘﻴـﺪًا . ﻓﻤـﻦ ﺧــﻼل ﻣﺤﺎﻛــﺎة ﻋﺪدﻳــﺔ ﺑﺎﺳﺘﺨﺪام ﺑ ﺮﻧﺎﻣﺞ ﻓﻴﻮﺳـﺎد ﺗﺘﺒﻊ اﻟﺒﺎﺣﺜﻮن ﺗﻄـﻮر ﻧـﻮاة ﺳـﺤﺎﺑﺔ ﻣﻨ ﻬـﺎرة إﱃ ﻧﻈـﺎم ﻳﺘﻜـﻮن ﻣـﻦ ﻧﺠـﻢ وﻗـﺮص واﻛﺘﺸﻔﻮا أن اﻻﻧﺘﻘﺎل ﻳﺤﺪث ﺗﺪرﻳﺠﻴًﺎ ﻋﱪ ﻣﻨﻄﻘﺔ ﻣﺤﺪدة اﻻﺗﺴﺎع . وﻗـﺪ ﺗﺮﻛـﺖ ﻫـﺬه اﻟﻌﻤﻠﻴــﺔ ﺑﺼــﻤﺔ ﻣﻤﻴــﺰة ﺗﻤﺜﻠﺖ ﰲ ﻗﻔـﺰة واﺿـﺤﺔ ﰲ ﺗﻮزﻳﻊ اﻟﺰﺧﻢ اﻟﺰاوي اﻟﻨﻮﻋ ﻲ وﻫﻮ ﻣﻘﻴﺎس ﻳﺼﻒ ﻛﻴﻔﻴـﺔ دوران اﻟﻐﺎز ﺗﺒﻌًﺎ ﻟﺒﻌﺪه ﻋـﻦ اﻟﻨﺠﻢ . وأوﺿﺢ داس ﻳﻨﺸﺄ »: وﺟــﻮد ﻣﻨﻄﻘــﺔ إﻧــﺪﻧﺮاﻧﺰ ﺑﺼــﻮرة ﻃﺒﻴﻌﻴــﺔ ﻧﺘﻴﺠــﺔ إﻋﺎدة ﺗﻮزﻳﻊ اﻟﻜﺘﻠﺔ واﻟﺰﺧﻢ اﻟﺰاوي أﺛﻨﺎء ﺗﺸﻜﻞ اﻷﻗﺮاص ﺣﻮل اﻟﻨﺠﻮم اﻟﻔﺘﻴﺔ . وﻫـﺬه اﻟﻌﻤﻠﻴ ـﺔ ﺗ ـﺘﺤﻜﻢ ﰲ ﻛﻴﻔﻴ ــﺔ اﻧﺘﺸ ــﺎر ا ـــﺎدة اﻟﺴﺎﻗﻄﺔ ﻣﻦ اﻟﻐﻼف واﻟﺘـﻲ ﺗــﺪور ﺑﴪــﻋﺔ أﻗــﻞ ﻣــﻦ ﺗﺪور ﺑ ـ ـ ﴪﻋﺔ أﻗﻞ ﻣـﻦ اﻟـ ﴪﻋﺔ اﻟﻜﺒﻠﺮﻳـﺔ ﻟﺘﻜـﻮﻳﻦ اﻟﻘـﺮص واﺳـﺘﻘﺮارﻫﺎ ﺗـﺪرﻳﺠﻴ ﰲ ﺎً ﺣﺮﻛـﺔ دوراﻧﻴـﺔ ﻣﻨﺘﻈﻤـﺔ «. وﻟﻠﺘﺤﻘـﻖ ﻣـﻦ وﺟﻮد ﻫﺬه ا ﻨﻄﻘﺔ ﰲ اﻟﻄﺒﻴﻌﺔ وﺟﻪ اﻟﻔﺮﻳـﻖ اﻫﺘﻤﺎﻣﻪ إﱃ اﻟﻨﺠﻢ اﻷوﱄ اﻟﻔﺘﻲ L1527 IRS ا ﻟﻮاﻗﻊ ﻋﲆ ﺑﻌﺪ ﻧﺤـﻮ 450 ﺳـﻨﺔ ﺿـﻮﺋﻴﺔ ﰲ ﺳﺤﺎﺑﺔ اﻟﺜﻮر اﻟﺠﺰﻳﺌﻴﺔ . وﺑﺎﺳﺘﺨﺪام ﺑﻴﺎﻧـﺎت ﺑﺮﻧﺎﻣﺞ إﻳﺪِﺳْـﻚ اﻟﺘـﺎﺑﻊ ﺼـﻔﻮﻓﺔ أ ـﺎ ﻋﺜـﺮ اﻟﺒﺎﺣﺜﻮن ﻋﲆ اﻟﺒﺼﻤﺔ ﻧﻔﺴﻬﺎ ﻟﻠﺰﺧﻢ اﻟﺰاوي اﻟﺘ ﻲ ﺗﻨﺒﺄت ﺑﻬﺎ ا ﺤﺎﻛﺎة اﻟﺤﺎﺳﻮﺑﻴﺔ . واﻣﺘﺪت اﻟﺘﻲ ﺗﻨﺒﺄت ﺑﻬﺎ ا ﺤﺎﻛﺎة اﻟﺤﺎﺳﻮﺑﻴﺔ . واﻣﺘﺪت ﻣﻨﻄﻘﺔ اﻻﻧﺘﻘﺎل ا ﻜﺘﺸﻔﺔ ﻋﱪ ﻧﻄـﺎق ﻳﺒﻠـﻎ ﻋﺮﺿﻪ ﻧﺤﻮ 16 وﺣﺪة ﻓﻠﻜﻴﺔ أي ﻣﺎ ﻳﻌﺎدل 16 ﻣﺮة ﻣﺘﻮﺳﻂ ا ﺴﺎﻓﺔ ﺑ اﻷرض واﻟﺸـﻤﺲ . وﻗﺎل ﺷﺎﻧﺘﺎﻧﻮ ﺑﺎﺳﻮ ا ـﺪﻳﺮ ا ﺆﻗـﺖ ﻟﻠﻤﻌﻬـﺪ اﻟﻜﻨـﺪي ﻟﻠﻔﻴﺰﻳـﺎء اﻟﻔﻠﻜﻴـﺔ اﻟﻨﻈﺮﻳـﺔ وأﺣـﺪ ا ﺸﺎرﻛ ﰲ اﻟﺪراﺳـﺔ :» ﻳﻤﺜـﻞ ﻫـﺬا ا ـﺆﴍ اﻟﺨﺎص ﺑﻤﻨﻄﻘﺔ إﻧﺪﻧﺮاﻧﺰ اﻧﻌﻜﺎﺳـ ﺎً اً ﻣﺒـﺎﴍ ﻟﻠﺘﺤ ﻮل اﻟﺘﺪرﻳﺠﻲ ﰲ اﻟﴪﻋﺔ اﻟﺪوراﻧﻴﺔ وﻳﻮﻓﺮ إﻃﺎر اً ﺗﺸﺨﻴﺼﻴ ﺎً ﻟﻔﻬﻢ اﻟﻌﻤﻠﻴﺎت اﻟﻔﻴﺰﻳﺎﺋﻴـﺔ اﻟﺘﻲ ﺗﻘﻮد ﺗﻄﻮر اﻷﻗﺮاص اﻟﻜﻮﻛﺒﻴﺔ «. وﻛﺎﻧﺖ اﻟﻘﺪ رة اﻟﻔﺎﺋﻘـﺔ ﺼـﻔﻮﻓﺔ أ ـﺎ ﻋـﲆ اﻟﺮﺻﺪ ﻋﺎﱄ اﻟﺪﻗﺔ ﻋﻨﴫ اً ﰲ ﺎً ﺣﺎﺳﻤ ﺗﺤﻘﻴـﻖ ﻫﺬا اﻻﻛﺘﺸﺎف إذ ﻣﻜ ﻨﺖ اﻟﻌﻠﻤﺎء ﻣـﻦ ﺗﻤﻴﻴـﺰ اﻟﺒﻨﻴﺔ اﻟﺪﻗﻴﻘﺔ ﻋﻨ ﺪ اﻟﺤﺪ اﻟﻔﺎﺻﻞ ﺑ اﻟﻐـﻼف واﻟﻘﺮص وﻫﻲ ﻣﻨﻄﻘﺔ ﻛﺎﻧﺖ ﺧﺎرج ﻣ ﺘﻨـﺎول ا ﺮاﺻــﺪ اﻟﺴــﺎﺑﻘﺔ . ﻣــﻦ ﺟﺎﻧﺒــﻪ أوﺿــﺢ ﻧﺎﺟﺎﻳﻮﳾ أوﻫﺎﳾ ا ﻟﺒﺎﺣﺚ اﻟﺮﺋﻴﴘ ﻟﱪﻧﺎﻣ ﺞ إﻳﺪِ ﺳْﻚ وأﺣﺪ ﻣﺆﻟﻔﻲ اﻟﺪراﺳﺔ :» إن اﻟﻔﺤـﺺ إﻳﺪِﺳْﻚ وأﺣﺪ ﻣﺆﻟﻔﻲ اﻟﺪراﺳﺔ : » إن اﻟﻔﺤﺺ اﻟﺪﻗﻴﻖ وا ﻘﺎر ﻧﺔ ﺑ اﻟﺘﻐـ اﻟﺸـﻌﺎﻋﻲ ﻟﻠـﺰﺧﻢ اﻟ ـﺰاوي اﻟﻨــﻮﻋﻲ ﰲ اﻟﺒﻴﺎﻧ ـﺎت اﻟﺮﺻــﺪﻳﺔ وﻧﺘــﺎﺋﺞ ا ﺤﺎﻛــﺎة ﺳـﺎﻋﺪا ﻋـﲆ ﺗﺤﺪﻳــﺪ اﻟ ـﺪﻟﻴﻞ اﻟﻮاﺿﺢ ﻋـﲆ وﺟـﻮد ﻣﻨﻄﻘـﺔ إﻧـﺪﻧﺮاﻧﺰ ﰲ اﻟﻨﻈـﺎم اﻟﻨﺠﻤـﻲ L1527 IRS . وﻳ ﺮﺳﺦ ﻫﺬا اﻻﻛﺘﺸﺎف ﻣﻔﻬﻮم إﻧــﺪﻧﺮاﻧﺰ ﺑﻮﺻــﻔﻪ ﻋﻨــ ﴫاً ـ أﺳﺎﺳــﻴ ﺎً ﰲ ﻋﻤﻠﻴــ ﺔ ﺗﺸــﻜﻞ اﻟﻨﺠـﻮم واﻷﻧﻈﻤـﺔ اﻟﻜﻮﻛﺒﻴـﺔ ﻛﻤﺎ ﻳﻔﺘﺢ اﻟﺒﺎب أﻣـﺎم اﻟﺒﺤـﺚ ﻋﻦ اﻟﺒﺼﻤﺔ ﻧﻔﺴﻬﺎ ﰲ أ ﻧﻈﻤـﺔ ﻧﺠﻤﻴــﺔ ﻓﺘﻴــﺔ أﺧــﺮى ﻋــﱪ ﻣﺠﺮﺗﻨــﺎ وﻳﺴــﻬﻢ ﰲ إﻋــﺎدة ﺻﻴﺎﻏﺔ ﻓﻬﻤﻨﺎ ﻟﻜﻴﻔﻴﺔ اﻧﺘﻘـﺎل ا ــﺎدة ﺑ ـ ا ﺮاﺣــﻞ ا ﺒﻜــﺮة ﻟﺘﻜـــﻮّن اﻟﻨﺠ ــﻮم وﺗﻄ ــﻮر اﻷﻗﺮاص اﻟﻜﻮﻛﺒﻴﺔ ﰲ اﻟﻔﻀـﺎء ﺑﺸﻜﻞ اﻛﺜﺮ دﻗﺔ وﻋﻤﻘﺎً . واﺧﺘﺘﻤﺖ داس ﻗﺎﺋﻠﺔ ﻧﻌﺘﻘﺪ »: ﻣــﻦ ﻧــﻮاحٍ ﻋﺪﻳــﺪ ة أن ﻫــﺬا اﻻﻛﺘﺸﺎف اﻟﻌﻠﻤﻲ ا ﻬﻢ ﻟـﻴﺲ .« ﺳﻮى اﻟﺒﺪاﻳﺔ - ﻳﻮﻟﻴﻮ ﺃﻏﺴﻄﺲ 2 0 2 6 اﻟﺼﻔﺤﺔ اﻟﺴﺎ ﻘﺔ : ﺗﺼﻮر ﻣﻔﺎﻫ ﻤﻲ ﻟﻤﻨﻄﻘﺔ إﻧﺪﻧﺮاﻧﺰوﻫﻲ اﻟﻤﻨﻄﻘﺔ اﻻ ﻧﺘﻘﺎﻟ ﺔ ﻋﻨﺪ ﺣـﺪود اﻟﻐـﻼف واﻟﻘﺮص ﺗﻈﻬﺮﻋﻠﻰﺷ واﻟ ﻞ ﺣﻠﻘﺔ ﻤﺮاء ﺗﺸ ﮫ اﻟـ ـ ـﺚ ﺗﻨﺘﻘـﻞ ﺣﺮﻛـﺔ اﻟﻐـﺎزﺗـﺪر ﺠ ﺎً ﺤﺰام ﺣ ﻣـﻦ ﺣﺮﻛـﺔ اﻷوﻟﻲ اﻟﻤﺤ ﻂ ﻨ ﻢ ﻓ اﻟﻐﻼف اﻟﻤﺘﺴﺎﻗﻂ إﻟﻰ اﻟﺪوران اﻟﻜ ﻠﺮيداﺧﻞ اﻟﻘﺮص اﻟ ﻮﻛ . ﻫﺬا رﺳﻢ ﺗﻮﺿﻴﺤﻲ ﻣﻮﻟﺪ ﺑﻮاﺳﻄﺔ اﻟﺬ ﺎء اﻻﺻﻄﻨﺎﻋﻲ ﻌﺘﻤﺪ ﻋﻠﻰﺧﺮﻄﺔ ﻣ ﺎﻧ ﺔ ﺛﻨﺎﺋ ﺔ اﻷ ﻌـﺎد ﻟــ اﻟـﺰ ﻢ اﻟـﺰاوي اﻟﻨﻮﻋﻲ ﻓﻲ اﻟﻤﺴﺘ ﻮى اﻻﺳﺘﻮاﺋﻲ ﻤـﺎ ﺗـﻢ اﻟـ ـ ـﺔ ـﺎة اﻟﻌﺪد ـﮫ ﻣـﻦ اﻟﻤﺤﺎ ﺤﺼﻮل ﻋﻠ . ﺗـﻮﻓﺮﺧﺮﻄـﺔ اﻟـﺰ ﻢ اﻟﺰاوي اﻟﻨﻮﻋﻲ ﻣﻨﻈﻮراُ ﺪﻳﻬ ﺎً ﻟﺮؤ ﺔ ﻣﻨﻄﻘﺔ إﻧﺪﻧﺮاﻧﺰ ﻣﻤﺎ ﻳﺠﻌﻞ د ﻨﺎﻣ ﻜ ﺘﻬﺎ أﻛ وﺿـﻮﺣﺎً ﻣـﻦ ﺧﺮﻄـﺔ ـــﺔ اﻟﺴـــﺮﻋﺔ اﻟﺪوراﻧ ـــﺎﺋ ﺘ اﻟﻔ اﻟﺒﻴﺌﺘـــ ـــﺔ ﻟﻠﻐـــﺎزﺑـــ وﺗﻮﺿـــﺢ اﻻﻧﺘﻘـــﺎل اﻟﺘـــﺪر ﺠﻲ ﻟﻠﺨﺼـــﺎﺋﺺ اﻟﺪ ﻨﺎﻣ ﻜ داﺧﻞ اﻟﻨﻈﺎم اﻟﻨ ﻤﻲ اﻟﻔ اﻟﻤﺨﺘﻠﻔﺘ .. [Indrani Das/ASIAA] اﻟﻨﻈﺎم اﻟﻨ ﻤﻲ اﻷوﻟﻲ اﻟﺸﺎب L1527 IRS ـﺎﻣ ا ﺗﻢ اﻟﺘﻘﺎﻃﮫ ﺑﻮاﺳﻄﺔ ـﺎم ) ﻧ ( ﻋﻠـﻰ ﺗﻠﺴ ﻮبﺟ ﻤﺲو ﺐ اﻟﻔﻀﺎﺋﻲ ﻣ ) اﻟﻠﻮﺣﺔ اﻟ ﺴﺮى ( وﺣﺮ ﺎت اﻟﻐﺎزاﻟﻤﺮﺻﻮدةﻓﻲﻫﺬا اﻟﻨﻈﺎم ﺗﻢ اﻟ واﻟ ـ ﺤﺼﻮل ﻋﻠﻴﻬﺎ ﺑﻮاﺳﻄﺔ ﺑﺮﺎﻣﺞ إ ﺪِﺳْﻚ ﻣﻦ ﻣﺮﺻـ ) ﺪ أﻟﻤـﺎ اﻟﻠﻮﺣـﺔ اﻟ ﻤـ .( ( أ) ُﻈﻬﺮ اﻟﺸ ﻞ اﻟﺘﻐ اﻟﻘﻄﺮي ﻟﻠـﺰ ﻢ اﻟـﺰاوي اﻟﻨـﻮﻋﻲو ( ب) ـﺔ اﺳـﺘﻨﺎداً اﻟﺴـﺮﻋﺔ اﻟﺪوراﻧ إﻟــﻰﻣ ﻮﻧـــﺎت اﻟﺴـــﺮﻋﺔ اﻟﻤﺰاﺣـــﺔ ﻧﺤـــﻮ اﻷزرق واﻷ ﻤــﺮ . وﺗﻌـــﺪّ اﻟﻘﻔـــﺰة ﻓـــﻲ اﻟﻤﻈﻬـــﺮ اﻟـــ ـ ﺠﺎﻧ ـﺎﻟﻠﻮن اﻟ ﻘـﺎﻟﻲد اﻟﻘﻄـﺮي اﻟﻤﺮﺻـﻮد ﻟﻠـﺰ ﻢ اﻟـﺰاوي اﻟﻨــﻮﻋﻲﻓـﻲ اﻟﻤﻨﻄﻘــﺔ اﻟﻤﻈﻠﻠــﺔ ﻟــ ﻼً ــﺚ ﺗﻨﺘﻘـــﻞ ﺣﺮﻛــﺔ اﻟﻐـــﺎز ﻣــﻦ اﻟﻐـــﻼف اﻟــﺪوار اﻟﺴـــﺎﻗﻂ إﻟــﻰ اﻟﻘـــﺮص ﻋﻠــﻰﻇــﺎﻫﺮة إﻧـــﺪﻧﺮاﻧﺰ ﺣ اﻟﻜ ﻠﺮي [(left) NASA, ESA, CSA, STScI; (right) Indrani Das/ASIAA]