Free Astronomy Magazine May-June 2025 ARABIC VERSION

MAY-JUNE2025 sure,andgravitybeing amongthemostimportant. Morespecifically,asfrag- mentscontractunderthe forceofgravity,theircores heatup.Ifacoreismassive enough,itwillbeginto fusehydrogen.Theout- wardpressurecreatedby that fusion counteracts gravity,stoppingcollapse andstabilizingtheobject (thenknownasastar). However,fragmentswhose coresarenotcompactand hot enough to burn hydro- gencontinuetocontractas long as they radiate away theirinternalheat. “The coolingofthesecloudsis importantbecauseifyou haveenoughinternalen- ergy,itwillfightthatgrav- ity,” saysMichaelMeyerof theUniversityofMichigan. “Ifthecloudscooleffi- ciently, they collapse and breakapart.” Fragmentationstopswhen a fragment becomes opaqueenoughtoreab- sorbitsownradiation, therebystoppingthecoolingand preventingfurthercollapse.Theories placed the lower limit of these frag- ments anywhere between one andtenJupitermasses.Thisstudysignif - icantly shrinks that range as Webb’s census counted up fragments of dif- ferent masses within the nebula. “As found in many previous studies, asyougotolowermasses,youactu- allygetmoreobjectsuptoaboutten timesthemassofJupiter.Inour study with the James Webb SpaceTelescope,wearesensitivedown to0.5timesthemassofJupiter,and wearefindingsignificantlyfewer and fewer things as you go belowten times the mass of Jupiter,” De Furioexplained. “Wefindfewer five- Jupiter-massobjectsthanten- Jupiter-massobjects,andwefind wayfewerthree-Jupiter-massob- jectsthanfive-Jupiter-massobjects. Wedon’treallyfindanyobjects belowtwoorthreeJupitermasses, and we expect to see them if they arethere,sowearehypothesizing thatthiscouldbethelimititself.” Meyer added, “Webb, for the first time,hasbeenabletoprobeupto andbeyondthatlimit.Ifthatlimit isreal,therereallyshouldn’tbeany one-Jupiter-massobjectsfree-float- ingoutinourMilkyWaygalaxy,un- lesstheywereformedasplanets andthenejectedoutofaplanetary system.” Browndwarfs,giventhedifficultyof findingthem,haveawealthofinfor- mationtoprovide,particularlyinstar formationandplanetary researchgiventheirsimilar- itiestobothstarsandplan- ets. NASA’s Hubble Space Telescopehasbeenonthe huntforthesebrown dwarfsfordecades.Even thoughHubblecan’tob- servethebrowndwarfsin theFlameNebulatoaslow amassasWebbcan,itwas crucialinidentifyingcandi- datesforfurtherstudy.This studyisanexampleofhow Webbtookthebaton— decadesofHubbledata from the Orion Molecular CloudComplex—anden- abled in-depth research. “It’sreallydifficulttodo this work, looking at browndwarfsdownto eventenJupitermasses, fromtheground,especially inregionslikethis.And havingexistingHubble dataoverthelast30years orsoallowedustoknow thatthisisareallyuseful star-formingregiontotar- get.Weneededtohave Webbtobeabletostudy thisparticularsciencetopic, ”saidDe Furio. “It’saquantumleapinourca- pabilities between understanding what was going on from Hubble. Webb is really opening an entirely new realm of possibilities, under- standing these objects,” explained astronomer Massimo Robberto of theSpaceTelescopeScienceInstitute. Thisteamiscontinuingtostudythe FlameNebula,usingWebb’sspectro- scopictoolstofurthercharacterize thedifferentobjectswithinitsdusty cocoon. “There’s a big overlap be- tweenthethingsthatcouldbeplan- etsandthethingsthatarevery,very low mass brown dwarfs,” Meyer stated. “And that’s our job in the nextfiveyears:tofigureoutwhichis whichandwhy.”  ﻣﺠﻠﺔ FreeAstronomy ﺎﻟﻌﺮ ﺔ 32 ﺑﺸــﻜﻞ أﻛﺜــﺮ ﺗﺤﺪﻳــﺪًا ﺪﻣﺎ ﻋﻨــ ﺗﻨﻜﻤﺶ اﻟﺸﻈﺎﻳﺎ ﺑﻔﻌﻞ اﻟﺠﺎذﺑﻴﺔ ﺗﺮﺗﻔﻊ درﺟﺔ ﺣﺮارة ﻧﻮاﺗﻬ ﺎ ﻓـﺈذا ﺑﻠﻐﺖ اﻟﻨﻮاة ﺣﺠﻤـﺎً ﺣﺮﺟـﺎً ﺗﺒـﺪأ ﺗ ﻔـﺎﻋﻼت اﻧـﺪﻣﺎج اﻟﻬﻴـﺪروﺟ اﻟﻨــﻮوي وﻳُﻌــﺎﻛﺲ اﻟﻀــﻐﻂ اﻟﺨﺎرﺟﻲ اﻟﻨﺎ ﺗﺞ ﻋﻦ ﻫﺬا اﻻﻧﺪﻣﺎج ﻗ ـﻮة اﻟﺠﺎذﺑﻴــﺔ ﻣﻤ ـﺎ ﻳــﺆ دي إﱃ اﺳﺘﻘﺮار اﻟﺠﺮ م وﺗﻜﻮﻳﻦ ﻧﺠﻢ أﻣﺎ اﻟﺸـﻈﺎﻳﺎ اﻟﺘـﻲ ﻻ ﺗﺒﻠــﻎ ﻧﻮاﺗﻬـﺎ اﻟﻀﻐﻂ أو اﻟﺤﺮار ة اﻟﻼزﻣ ﻟﺒﺪء اﻻﻧــﺪﻣﺎج اﻟﻨــﻮوي ﻓﺘﺴــﺘﻤﺮ ﰲ اﻻﻧ ﻜﻤﺎش ﻃﺎ ﺎ ﺗﺸـﻊ ﺣﺮارﺗﻬـﺎ اﻟﺪاﺧﻠﻴﺔ وﻳﻮﺿﺢ ﻣﺎﻳﻜـﻞ ﻣـﺎﻳﺮ ﻣـﻦ ﺟﺎﻣﻌـﺔ ﻣﻴﺸـﻴﻐﺎن ﻳُﻌـﺪ " : ﺗﱪﻳﺪ اﻟﺴﺤﺐ اﻟﺠﺰﻳﺌﻴﺔ أﻣﺮ اً ﺑﺎﻟﻎ اﻷﻫﻤﻴـﺔ، ﻷﻧـﻪ ﰲ ﺣـﺎل اﻣــﺘﻼك ﻃﺎﻗــﺔ داﺧﻠﻴــﺔ ﻛﺎﻓﻴ ـ ﺔ ﻓﺈﻧﻬــﺎ ﺳـﺘﻘﺎوم اﻻﻧﻬﻴـﺎر اﻟﺠـﺬﺑﻲ وإذا ﺑـﺮدت اﻟﺴـ ﺤﺐ ﺑﻜﻔـﺎءة ﻓﺈﻧﻬـﺎ ﺳــﺘﻨﻬﺎر وﺗﺘﻔﺘــﺖ " وﻳﺘﻮﻗــﻒ اﻟﺘﻔﺘ ـﺖ ﻋﻨـﺪﻣﺎ ﻳﺼـﺒﺢ اﻟﺠـﺰء ﻛﺜﻴﻔًـﺎ ﺑﻤـﺎ ﻳﻜﻔـﻲ ﻻﻣﺘﺼــﺎص إﺷﻌﺎﻋﻪ اﻟﺬاﺗﻲ ﻣﻤﺎ ﻳﻌﻴﻖ اﻟﺘﱪﻳﺪ وﻳﺤﻮ ل دون ا ﺰﻳﺪ ﻣـﻦ اﻻﻧﻬﻴـﺎر اﻟﺠـﺬﺑﻲ وﻗـﺪ ﺣـﺪدت اﻟﻨﻤـﺎذج اﻟﻨﻈﺮﻳﺔ اﻟﺤﺪ اﻷدﻧﻰ ﻟﻜﺘﻠﺔ ﻫـﺬه ﻷ ﻰ ﻟﻜﺘﻠﺔ ﻫﺬه اﻷﺟﺰاء ﺑﻤﺎ ﻳـﱰاوح ﺑـ ﻛﺘﻠـﺔ واﺣـﺪة وﻋـ ـ ﴩﻛﺘـﻞ . ﻣﺸﱰﻳّﺔ وﻗﻠّﺼﺖ ﻫﺬ ه اﻟﺪراﺳﺔ ﻫﺬا اﻟﻨﻄﺎق ﺑﺸ ـﻜﻞ ﻣﻠﺤ ـﻮظ ـ ﺣﻴــﺚ أﺣ ـ ﴡ ﺗﻌــﺪاد ﺗﻠﺴﻜﻮب وﻳﺐ أﺟﺮاﻣـ ﺎً ذات ﻛﺘـﻞ ﻣﺘﻨﻮﻋـﺔ داﺧﻞ اﻟﺴﺪﻳﻢ . ﻳﻮﺿﺢ دي ﻓﻮرﻳﻮ " : ﻛﻤﺎ ﻫﻮ ﻣﺒ ﰲ اﻟﻌﺪﻳﺪ ﻣﻦ اﻟﺪراﺳﺎت اﻟﺴﺎﺑﻘﺔ ﻛﻠﻤﺎ اﺗﺠﻬﻨﺎ ﻧﺤﻮ ﻛﺘﻞ أﻗﻞ ﻧﺮﺻﺪ ﻋﺪد اً أﻛـﱪ ﻣـﻦ اﻷﺟﺮام ﺣﺘﻰ ﺣﻮ اﱄ ﻋﴩة أﺿـﻌﺎف اﻟﻜﺘﻠـﺔ ا ﺸﱰﻳّﺔ وﰲ دراﺳﺘﻨﺎ ﺑ ﺎﺳﺘﺨﺪام ﺗﻠﺴـﻜﻮب ﺟﻴﻤﺲ وﻳﺐ اﻟﻔﻀﺎﺋﻲ ﺑﻠﻐـﺖ ﺣﺴ ﺎﺳـﻴﺘﻨﺎ 0.5) ( ﻛﺘﻠﺔ ا ﺸﱰي ووﺟﺪﻧﺎ ﺗﻨﺎﻗﺼ ﺎً اً ﻛﺒـ ﰲ ﻋﺪد اﻷﺟﺮام ﻛﻠﻤﺎ اﻧﺨﻔﻀﺖ اﻟﻜﺘﻠـﺔ ﻋـﻦ ﻋﴩة أﺿﻌﺎف اﻟ ﻜﺘﻠﺔ ا ﺸﱰﻳّﺔ ﻓﻘﺪ رﺻﺪﻧﺎ اً ﻋﺪد أﻗﻞ ﺑﺨﻤﺲ ﻣـﺮات ﻣـﻦ اﻷﺟـﺮام ذات اﻟﻜﺘﻠﺔ ا ﺸﱰﻳّﺔ ﻣﻘﺎ رﻧـﺔ ﺑﺘﻠـﻚ اﻟﺘـﻲ ﺗﺒﻠـﻎ ﻋﴩة أﺿـﻌﺎﻓﻬﺎ وﻋـﺪدًا أﻗـﻞ ﺑﻜﺜـ ﻣـﻦ اﻷﺟﺮام ذات اﻟﺜﻼﺛﺔ أﺿﻌﺎف ﻣﻘﺎرﻧـﺔ ﺑﺘﻠـﻚ اﻷﺟﺮام ذات اﻟﺜﻼﺛﺔ أﺿﻌ ﺎف ﻣﻘﺎرﻧـﺔ ﺑﺘﻠـﻚ ذات اﻟﺨﻤﺴﺔ أﺿﻌﺎف وﻟﻢ ﻧﺮﺻﺪ ﻓﻌﻠﻴـ أي ﺎً أﺟﺮام ﺗﻘﻞ ﻛﺘﻠﺘﻬـﺎ ﻋـﻦ ﺿـﻌﻔﻲ أو ﺛﻼﺛـﺔ أﺿﻌﺎف اﻟﻜﺘﻠﺔ ا ﺸﱰﻳّﺔ وﻧﺘﻮﻗﻊ رﺻﺪﻫﺎ إن وُﺟﺪت ﻟﺬا ﻧﻔﱰض أن ﻫﺬا ﻗـﺪ ﻳ ﻤﺜـﻞ اﻟﺤـﺪ اﻷدﻧﻰ اﻟﻔﻌﲇ ﻟﻠﻜﺘﻠﺔ . أﺿﺎف ﻣﺎﻳﺮ " : ﻟﻘﺪ ﺗﻤﻜﻦ وﻳـﺐ وﻷول ﻣـﺮة ﻣﻦ ا ﺳﺘﻜﺸﺎف ﻫﺬا اﻟﻨﻄﺎق وﻣﺎ دوﻧﻪ ﺑﺪﻗـﺔ ﻓﺈذا ﻛﺎن ﻫﺬا اﻟﺤﺪ ﺣﻘﻴﻘﻴﺎً ﻓﻜﻴﻒ ﻳﻜـﻮن ﰲ ﻣﺠﺮﺗﻨﺎ أي ﺟﺮم ﻣﻨﻔﺮد ﺑﻜﺘﻠﺔ ﻣﺸﱰﻳّﺔ ﻳﻌﻮم ﺑﺤﺮﻳﺔ ﰲ ﻣﺠﺮﺗﻨﺎ درب اﻟﺘﺒﺎﻧﺔ إﻻ إذا ﻛﺎن ﻗﺪ ﺗﺤﻮل إﱃ ﻛﻮﻛﺐ وﻗُﺬف ﻣ ﻦ ﻧﻈﺎم ﻛﻮﻛﺒﻲ ." اً ﻧﻈﺮ ﻟﺼﻌﻮﺑﺔ رﺻﺪ اﻷﻗـﺰام اﻟﺒﻨﻴـﺔ ﻓﺈﻧﻬـﺎ ﺗﻘﺪم ﺑﻴﺎﻧﺎت ﻗﻴﻤﺔ ﰲ ﻣﺠﺎﱄ ﺗﻜﻮﻳﻦ اﻟﻨﺠﻮم وأﺑﺤﺎث اﻟﻜﻮ اﻛﺐ ﻟﺘﺸـﺎﺑﻬﻬﺎ ﻣـﻊ اﻟﻨﺠـﻮم واﻟﻜﻮاﻛــﺐ وﻗــﺪ دأب ﺗﻠﺴــﻜﻮب ﻫﺎﺑــﻞ اﻟﻔﻀﺎﺋﻲ اﻟﺘﺎﺑﻊ ﻟﻨﺎﺳﺎ ﻋﲆ اﻟﺒﺤﺚ ﻋﻦ ﻫﺬه اﻷﻗﺰام ﻟﻌﻘـﻮد . ورﻏـﻢ أن ﻫﺎﺑـﻞ ﻻ ﻳﺘﻤﺘـﻊ اﻷﻗﺰام ﻟﻌﻘﻮد ورﻏﻢ أن ﺗﻠﺴﻜﻮب ﻫﺎﺑﻞ ﻻ ﻳﺘﻤﺘﻊ ﺑﻘـﺪرة ﺗﻠﺴـﻜﻮب وﻳﺐ ﻋﲆ رﺻﺪ اﻟـﱰاﻛﻢ اﻟﺒﻄـ ﻲء ﻟﻸﻗﺰام اﻟﺒﻨﻴﺔ ﰲ ﺳﺪﻳﻢ اﻟﻠﻬـﺐ ﻻ أﻧﻪ ﻛﺎن ﺣﺎﺳﻤًﺎ ﰲ ﺗﺤﺪﻳﺪ اﻟﻨ ﺠﻮم ا ﺮﺷﺤﺔ ﺰﻳـﺪ ﻣـﻦ اﻟﺪراﺳـﺎت . ﺗﻤﺜﻞ ﻫﺬه اﻟﺪراﺳـﺔ ﻣﺜـﺎﻻً ﻋـﲆ ﻛﻴﻔﻴﺔ اﺳﺘﺜﻤﺎر وﻳﺐ ﻟﻌﻘﻮد ﻣـﻦ ﺑﻴﺎﻧﺎت ﻫﺎﺑﻞ ﻣﻦ ﻣﺠﻤﻊ ﺳـﺤﺎﺑﺔ اﻟﺠﺒﺎر اﻟﺠﺰﻳﺌ ﻴـﺔ وﺗﻤﻜﻴﻨـﻪ ﻣـﻦ إﺟﺮاء ﺑﺤﺚ ﻣﻌﻤﻖ . ﻳﻮﺿــﺢ دي ﻓﻮرﻳــﻮ " : ﻳﺼــﻌﺐ إﺟـﺮاء ﻫــﺬا اﻟﻌﻤــﻞ ﺑ ـﺎﻟﻨﻈﺮ إﱃ اﻷﻗﺰام اﻟﺒﻨﻴﺔ وﺻﻮﻻً إ ﱃ اﻟﻜﻮاﻛﺐ ذات اﻟﻜﺘﻠﺔ ا ﺸﱰﻳّﺔ ﻣـﻦ اﻷرض ﺧﺎﺻـﺔ ﰲ ﻣﻨـﺎﻃﻖ ﻛﻬـﺬه وﻗـﺪ أﺗﺎﺣﺖ ﻟﻨﺎ ﺑﻴﺎﻧﺎت ﺗﻠﺴﻜﻮب ﻫﺎﺑﻞ ا ﺘﻮﻓﺮة ﻋﲆ ﻣﺪار اﻟﺜﻼﺛ ﻋﺎﻣًـﺎ ا ﺎﺿـﻴﺔ أو ﻧﺤـﻮ ذﻟ ـﻚ إدراك أن ﻫ ـﺬه ﻣﻨﻄﻘ ـﺔ ﺑﺎﻟﻐ ـﺔ اﻷﻫﻤﻴــﺔ ﻟﺘﻜـــﻮﻳﻦ اﻟﻨﺠـــﻮم وﻳﺠـــ ﺐ اﺳــﺘﻬﺪاﻓﻬﺎ وﻛﻨــﺎ ﺑﺤﺎﺟــﺔ إﱃ ﺗﻠﺴـﻜﻮب وﻳ ـﺐ ﻟﺪراﺳـﺔ ﻫ ـ ﺬا ا ﻮﺿﻮع اﻟﻌﻠﻤـﻲ ﺗﺤﺪﻳـﺪ . اً إﻧﻬـﺎ ﻧﻘﻠﺔ ﻧﻮﻋﻴﺔ ﰲ ﻗﺪراﺗﻨﺎ ﻟﻔﻬـﻢ ﻣـﺎ ﻛﻨﺎ ﻧﺮﺻﺪه ﻣـﻦ ﺧـﻼل ﻫﺎﺑـﻞ ." وﻳﻀﻴﻒ ﻋـﺎﻟﻢ اﻟﻔﻠـﻚ ﻣﺎﺳـﻴﻤﻮ ﻳﻀﻴﻒ ﻋﺎﻟﻢ اﻟﻔﻠﻚ اﻟﻘﺪﻳﺮ ﻣﺎﺳﻴﻤﻮ روﺑﺮﺗ ﻣﻦ ﻣﻌﻬﺪ ﻋﻠﻮم ﺗﻠﺴﻜﻮب اﻟﻔﻀﺎء " : ﻳﻔـﺘﺢ ﺗﻠﺴﻜﻮب وﻳﺐ آﻓﺎﻗ ﺎً ﺟﺪﻳـﺪة ﺗﻤﺎﻣـ ﺎً وﻏـ ﻣﺴــﺒﻮﻗﺔ ﻻﺳﺘﻜﺸــﺎف ﻫــﺬه اﻷﺟــﺮ ام اﻟﺴﻤﺎوﻳﺔ اﻟﻐﺎﻣﻀﺔ وا ﻌﻘﺪة ." ﻳﻮاﺻﻞ ﻫﺬا اﻟﻔﺮﻳﻖ دراﺳﺔ ﺳـﺪﻳﻢ اﻟﺸـﻌﻠﺔ ﺑﺸﻜﻞ ﻣﺴﺘﻤﺮ ﺑﺎﺳﺘﺨﺪام أدوات ﺗﻠﺴـﻜﻮب وﻳﺐ اﻟﻄﻴﻔﻴ ﺔ ا ﺘﻄـﻮرة واﻟﺪﻗﻴﻘـﺔ ﻹﺟـﺮاء ﺗﻮﺻـﻴﻔﺎت ﺗﻔﺼـﻴﻠﻴﺔ ﻟﻸﺟـﺮام ا ﺨﺘﻠﻔ ـﺔ ا ﺘﻮارﻳ ﺔ داﺧﻞ ﴍﻧﻘﺘـﻪ ا ﻐـﱪة اﻟﻜﺜﻴﻔـﺔ . ﻳﺸ ﻣﺎﻳﺮ ﺑﺈﺳﻬﺎب ﻣﻮﺿﺤً : "ﺎ ﻫﻨﺎك ﺗﺪاﺧﻞ ﻛﺒ ﺑـ اﻷﺟـﺮام اﻟﺘـﻲ ﻳﻤﻜـﻦ أن ﺗﻜـﻮن ﻛﻮاﻛﺐ ﻋﻤﻼﻗﺔ واﻷﺟﺮام اﻟﺘـﻲ ﻫـﻲ أﻗـﺰام ﺑﻨﻴﺔ ذات ﻛﺘﻠﺔ ﻣﻨﺨﻔﻀﺔ ﻟﻠﻐﺎﻳﺔ وﻫﺬه ﻫـﻲ ﻣﻬﻤﺘﻨ ـﺎ اﻟﺮﺋﻴﺴـ ﻴﺔ ﰲ اﻟﺴـﻨﻮات اﻟﺨﻤ ـﺲ ا ﻘﺒﻠﺔ : ﺗﺤﺪﻳﺪ ﻃﺒﻴﻌﺔ ﻫﺬه اﻷﺟﺮام وأﺳﺒﺎب اﺧﺘﻼﻓ ﺎﺗ ﻬﺎ اﻟﺠﻮﻫﺮﻳﺔ ". ﻈﻬـــــﺮ رﺻـــــﺪ ﺗﻠﺴــــــ ﻮبﻫﺎﺑـــــﻞ اﻟﻔﻀـــــﺎﺋﻲورﺻــــــﺪ ــــــﺪﻳﻮ ﻣﻘﺎر ـــــﺔً ﺑـــــ ﻫـــــﺬا اﻟﻔ ﺗﻠﺴــ ــﺐ اﻟﻔﻀـــﺎﺋﻲ ﻟﺴــﺪ ﻢ ﻮبﺟــ ﻤﺲو اﻟﺸــﻌﻠﺔ وﻫـــﻮ ﺳــﺪ ﻢ ﻧ ﻤــﻲﺣـــﺪ ﺚ ا ﻟﺘ ﻮﻳﻦ ﻻ ﺘﺠﺎوز ﻋﻤﺮﻩ ﻣﻠﻴﻮن ﻋﺎم وﺗُﺮﻛﺰﻫﺬﻩ اﻟﻤﻘﺎرﺔ ﻋﻠﻰ إﺑﺮازﺛﻼﺛﺔ أﺟ ﺮام ﻣﻨﺨﻔﻀـﺔ اﻟﻜﺘﻠــﺔ . ﻓﻔــﻲ رﺻــﺪ ﻫﺎﺑـﻞ ــﺎر واﻟﻐــﺎزاﻟﻜﺜ ﻔــﺎن اﻟﻤﻮﺟــﻮد ﻳﺤﺠـﺐ اﻟﻐ ان ﻓﻲ اﻟﻤﻨﻄﻘﺔ رؤ ﺔ ﻫﺬﻩ اﻷﺟﺮام اﻟﺼـﻐ ة . ﺑ ﻨﻤـﺎ ﺗﻈﻬـﺮﻫـﺬﻩ اﻷﺟـﺮام ﺑﻮﺿـﻮح ــــﺐ ﻧﻈــــﺮًا ﻟــــ ﻓــــﻲ رﺻــــﺪ و ـ ــــﺔ ﻟﻠﻀــــﻮء ﺗﺤــــﺖ اﻷ ﻤــــﺮ ــــﺐ اﻟﻌﺎﻟ ﺤﺴﺎﺳ ﺔ ﺗﻠﺴــــ ﻮب و ـاﻟ ﺨﺎﻓﺖ اﻟﻤﻨ ﻌﺚ ﻣﻨﻬﺎ . [(NASA,ESA,CSA,AlyssaPagan(STScI)] ﻣﺎﻳﻮ - ﻳﻮﻧﻴﻮ 2 0 2 5