Free Astronomy Magazine May-June 2024 ARABIC VERSION

thedust-andgas-richdiscsthaten- velopyoungstars—theverycradles ofplanetformation.Thesearebest foundinhugegascloudswherethe starsthemselvesareforming.Much like mature planetary systems, the newimagesshowcasetheextraordi- narydiversityofplanet-formingdiscs. “Someofthesediscsshowhugespi- ral arms, presumably driven by the intricateballetoforbitingplanets,” says Ginski. “Others show rings and large cavities carved out by form- ing planets, while yet others seem smooth and almost dormant among all this bustle of activity,” adds An- tonio Garufi, an astronomer at the ArcetriAstrophysicalObservatory, ItalianNationalInstitute for Astrophysics (INAF), and lead author of one of the papers. Theteamstudiedatotal of 86 stars across three different star-forming regions of our galaxy: TaurusandChamaeleon I,botharound600light- years from Earth, and Orion, a gas-rich cloud about 1600 light-years from us that is knownto be the birthplace of severalstarsmoremas- sive than the Sun. The observations were gathered by a large in- ternational team, com- prising scientists from morethan10countries. The team was able to glean several key in- sightsfromthedataset. For example, in Orion theyfoundthatstarsin groups of two or more were less likely to have large planet-forming discs.Thisisasignificant resultgiventhat,unlike our Sun, most stars in our galaxy have com- panions.Aswellasthis, the uneven appearance of the discs in this re- gion suggests the possi- bilityofmassiveplanets embeddedwithinthem, which could be causing the discs to warp and become misaligned. While planet-forming discs can ex- tendfordistanceshundredsof times greater than the distance be- tween Earth and the Sun, their loca- tion several hundreds of light-years from us makes them appear as tiny pinpricks in the night sky. To observe the discs, the team em- ployedthesophisticatedSpectro- 44 ﻣﺠﻠﺔ FreeAstronomy ﺎﻟﻌﺮ ﺔ اﻷﻗـــﺮاص اﻟﻤ ﻮﻧـــﺔ ﻟﻠ ﻮاﻛـــﺐﺣـــﻮل اﻟﻨﺠـــﻮم اﻟﺸـــﺎ ﺔ وﻣﻮﻗﻌﻬـــﺎ داﺧـــﻞﺳـــﺤﺎ ﺔ ﺗـــﺎو ﺑـــﺮوس ـــﺔ ﺎﻟﻐـــﺎز اﻟﻐﻨ ﻋﻠـــﻰ ﻣﺴـــﺎﻓﺔ ﺣﻮاﻟﻲ 600 ﺳﻨﺔ ﺿﻮﺋ ﺔ ﻣـﻦ اﻷرض . ﺗـﻢ اﻟﺘﻘـﺎط اﻟﺼـﻮراﻟﻤﺬﻫﻠـﺔ ﻟﻸﻗـﺮاص ﺎﺳـﺘﺨﺪام أداة أﺑﺤـﺎث اﻟ ﻮاﻛـﺐ ـﺔ اﻟﻨ ﻤ ـﺔ ﻋﺎﻟ اﻟﺘ ﺎﻳﻦ اﻟﻄ ﻔﻲ واﻻﺳﺘﻘﻄﺎﺑﻲ ) SPHERE ( اﻟﻤﺜ ﺘﺔ ﻋﻠﻰ اﻟﺘﻠﺴـ ﻮب اﻟﻜﺒـ ﺟـﺪ اً اﻟﺘـﺎﺑﻊ ﻟﻠﻤﺮﺻـﺪ اﻷوروﺑـﻲ اﻟـ ـ ﺠﻨﻮﺑﻲ وﻓـﻲ اﻟﻤ ﻤﻞ رﺻﺪ اﻟﻔﺮﻖ 43 ﺎً ﻧ ﻤ ﻓﻲﻣﻨﻄﻘﺔ ﺑﺮج اﻟﺜﻮر ، و ﻠﻬﺎ ﻣﺼﻮرة ﻫﻨﺎ ) رﻏﻢ أﻧﮫ ﺗﻢ اﻛﺘﺸﺎف اﻷﻗﺮاصاﻟﻤ ﻮﻧﺔ ﻟﻠ ﻮاﻛﺐ ﻓﻲ 39 ﻣﻦ ﻫﺬﻩ اﻷﻫﺪافﻓﻘﻂ ( ] ESO/A.Garufietal.;IRAS [. واﻷﻗــﺮاص اﻟﻐﻨﻴــﺔ ﺑﺎﻟﻐﺒ ـﺎر واﻟﻐﺎز اﻟﺘﻲ ﺗﺤﻴﻂ ﺑـﺎﻟﻨﺠﻮم اﻟﺸـﺎ ﺑﺔ، ﻫـﻲ ﻣﻬـﺪ ﺗﻜـﻮﻳﻦ اﻟﻜﻮاﻛﺐ و ﻣﻦ اﻷﻓﻀﻞ اﻟﻌﺜﻮر ﻋﻠﻴﻬـﺎ ﰲ اﻟﺴـﺤﺐ اﻟﻐﺎزﻳــ ﺔ اﻟﻀــﺨﻤﺔ ﺣﻴــﺚ ﺗﺘﺸــﻜﻞ اﻟﻨﺠﻮم ﻧﻔﺴـﻬﺎ وﻛﻤـﺎ ﻫـﻮ اﻟﺤﺎل ﻣﻊ أﻧﻈﻤـﺔ اﻟﻜﻮاﻛـﺐ اﻟﻨﺎﺿــﺠﺔ ﺗُﻈﻬــﺮ اﻟﺼــﻮر اﻟﺠﺪﻳﺪة اﻟﺘﻨـﻮع اﻻﺳـﺘﺜﻨﺎﺋﻲ ﻟﻸﻗﺮاص ا ﻜﻮﻧﺔ ﻟﻠﻜﻮاﻛﺐ . ﻳﻘ ـﻮل ﺟﻴﻨﺴـﻜﻲ " : ﺗﻈﻬــﺮ ﺑﻌﺾ ﻫﺬه اﻷﻗـﺮاص أذرﻋًـﺎ ﺣﻠﺰوﻧﻴﺔ ﺿـﺨﻤﺔ، ﻳُ ﻔـﱰض أﻧﻬﺎ ﻣﺪﻓﻮﻋﺔ ﺑﺎﻟﺒﺎﻟﻴﻪ ا ﻌﻘﺪة ﻨﻊ اﻟﻜﻮاﻛﺐ ". ﻳﻀﻴﻒ أﻧﻄﻮﻧﻴﻮ ﺟﺎروﰲ ﻋﺎﻟِﻢ اﻟﻔﻠـﻚ ﰲ ﻣﺮﺻـﺪ أرﺳــﻴﱰي ﻟﻠﻔﻴﺰﻳ ـﺎء اﻟﻔﻠﻜﻴ ـﺔ، اﻟﺘــﺎﺑﻊ ﻟﻠﻤﻌﻬ ـﺪ اﻟــﻮﻃﻨﻲ اﻹﻳﻄــﺎﱄ ﻟﻠﻔﻴﺰﻳــﺎء اﻟﻔﻠﻜﻴـﺔ وا ﺆﻟـﻒ اﻟﺮﺋﻴﴘ ﻟﻮاﺣﺪة ﻣـﻦ اﻷوراق ": ﺗُﻈﻬِﺮ ﺻﻮر أﺧﺮى ﺣﻠﻘﺎت وﺗﺠﻮﻳﻔﺎت ﻛﺒ ة ﺗﻢ ﻧﺤﺘﻬـﺎ ﻧﺘﻴﺠـﺔ ﺗﺸــﻜﻞ اﻟﻜﻮاﻛــﺐ ﰲ ﺣــ ﺗﺒــﺪو ﺻــﻮر أﺧ ـﺮى ﺳﻠﺴﺔ وﺧﺎﻣﻠﺔ ﺗﻘﺮﻳﺒ ﺎً وﺳﻂ ﻛﻞ ﻫﺬا اﻟﻨﺸﺎط اﻟﺼﺎﺧﺐ «.. ﻗ ـﺎم اﻟﻔﺮﻳــﻖ ﺑﺪراﺳــﺔ ﻣــﺎ ﻣﺠﻤﻮﻋﻪ 86 ﺎً ﻧﺠﻤ ﻋﱪ ﺛﻼث ﻣﻨ ـﺎﻃﻖ ﻣﺨﺘﻠﻔ ـﺔ ﻟﺘﺸــﻜﻞ اﻟﻨﺠﻮم ﰲ ﻣﺠﺮﺗﻨﺎ : ﺑﺮج اﻟﺜﻮر واﻟﺤﺮﺑﺎء I وﻛﻼﻫﻤﺎ ﻳﻘﻊ ﻋﲆ ﺑﻌﺪ ﺣﻮاﱄ ٦٠٠ ﻣﺴﺎﻓﺔ ﺳﻨﺔ ﺿﻮﺋﻴﺔ ﺣﻮاﱄ 600 ﺳﻨﺔ ﺿـﻮﺋﻴﺔ ﻣـﻦ اﻷرض وأورﻳﻮن، وﻫﻲ ﺳـﺤﺎﺑﺔ ﻏﻨﻴـﺔ ﺑﺎﻟﻐـﺎز ﺗﺒﻌـﺪ ﺣﻮاﱄ 1600 ﺳﻨﺔ ﺿﻮﺋﻴﺔ ﻋﻨﺎ وا ﻌﺮ وﻓﺔ ﺑﺄﻧﻬﺎ ﻣﺴـﻘﻂ رأس ﻋـﺪة ﻧﺠـﻮم أﻛـﱪ ﻣـﻦ ﻛﺘﻠـﺔ اﻟﺸﻤ ﻟ. ﺲ ﻘﺪ ﻗﺎم ﺑﺠﻤ رﺻﺎد ﻊ اﻷ ﻓﺮﻳـﻖ دوﱄ ﻛﺒـ ﻳﻀـﻢ ﻋﻠﻤـﺎء ﻣـﻦ أﻛﺜـﺮ ﻣـﻦ 10 دول و ﺗﻤﻜﻦ اﻟﻔﺮﻳﻖ ﻣﻦ اﺳـﺘﺨﻼص اﻟﻌﺪﻳـﺪ ﻣـﻦ اﻷﻓﻜﺎر اﻟﺮﺋﻴﺴﻴﺔ ﻣﻦ ﻣﺠﻤﻮﻋﺔ اﻟﺒﻴﺎﻧﺎت . اﻷﻓﻜﺎر اﻟﺮﺋﻴﺴﻴﺔ ﻣﻦ ﻣﺠﻤﻮﻋﺔ اﻟﺒﻴﺎﻧﺎت . ﻋﲆ ﺳﺒﻴﻞ ا ﺜﺎل، وﺟـﺪوا ﰲ ﺳـﺤﺎﺑﻰ أورﻳـﻮن أن اﻟﻨﺠﻮم ا ﻮﺟﻮدة ﰲ ﻣﺠﻤﻮﻋـﺎت ﻣﻜﻮﻧـﺔ ﻣـﻦ ﻧﺠﻤ أو أﻛﺜﺮ ﻛﺎﻧﺖ أﻗـﻞ اﺣﺘﻤـﺎﻻ ﻻﻣـ ﺘﻼك أﻗﺮاص ﻛﺒ ة ﻟﺘﻜﻮﻳﻦ اﻟﻜﻮاﻛﺐ وﻫﺬه ﻧﺘﻴﺠـﺔ ﻣﻬﻤﺔ ﻧﻈﺮا ﻷن ﻣﻌﻈﻢ اﻟﻨﺠﻮم ﰲ ﻣﺠﺮﺗﻨﺎ ﻋﲆ ﻋﻜﺲ اﻟﺸﻤﺲ ﻟﻬﺎ . ﻣﺮاﻓﻖ اﻹﺿﺎﻓﺔ ان ا ﻈﻬﺮ ﻓﺈن ا ﻈﻬﺮ ﻏ ا ﺘﺴﺎوي ﻟﻸﻗـﺮاص ﰲ ﻫـﺬه ﻏ ا ﺘﺴـﺎوي ﻟﻸﻗـﺮاص ﻳﺸـ إﱃ إﻣﻜﺎﻧﻴـﺔ وﺟــﻮد ﻛﻮاﻛــﺐ ﺿــﺨﻤﺔ ﻓﻴﻬــﺎ ﺗﺘﺴ ـﺒﺐ ﰲ اﻋﻮﺟﺎج اﻷﻗﺮاص واﻧﺤﺮاﻓﻬـﺎ . إن اﻷﻗـﺮاص ا ﻜﻮﻧﺔ ﻟﻠﻜﻮاﻛﺐ ﻗﺪ ﺗﻤﺘﺪ ﺴﺎﻓﺔ أﻛﱪ ﺑﻤﺌـﺎت ا ـ ﺮات ﻣـﻦ ا ﺴـﺎﻓﺔ ﺑـ اﻷرض واﻟﺸـﻤﺲ وﺑﻌﺪﻫﺎ ﻋﻨﺎ ﻋﺪة ﻣﺌﺎت ﻣﻦ اﻟﺴﻨ اﻟﻀـﻮﺋﻴﺔ ﻳﺠﻌﻠﻬﺎ ﻣﺜﻞ ـﺻ وﻣﻀﺎت . ﻤﺎء اﻟﻠﻴﻞ ﺳ ﻐ ة ﰲ - ﻣﺎﻳﻮ ﻳﻮﻧﻴﻮ 2 0 2 4