Free Astronomy Magazine May-June 2024 ARABIC VERSION

“Taking part in such an important discovery in the iconic HL Tauri disc was beyond what I had ever expected for my first research experience in as- tronomy,” addsMathieuVanderDoncktfromthe University of Liège, Belgium, who was a master’s student when he participated in the research. Asignificantamountofwaterwasfoundinthere- gionwhereaknowngapintheHLTauridiscexists. Ring- shapedgapsarecarvedoutingas-anddust- rich discs by orbiting young planet-like bodies as theygatherupmaterialandgrow. “Ourrecentim- ages reveal a substantial quantity of water vapour atarangeofdistancesfromthestarthatinclude agapwhereaplanetcouldpotentiallybeforming atthepresenttime,” saysFacchini.Thissuggests that this water vapour could affect the chemical composition of planets forming in those regions. Observingwaterwithaground-basedtelescopeis no mean feat as the abundant water vapour in Earth’s atmosphere degrades the astronomical sig- nals.ALMA,operatedbyESOtogetherwithitsin- ternational partners, is an array of telescopes in theChileanAtacamaDesertatabout5000metres elevationthatwasbuiltinahighanddryenviron- ment specifically to minimise this degradation, providing exceptional observing conditions. “Todate,ALMAistheonlyfacilityabletospatially resolve water in a cool planet-forming disc,” says co-author Wouter Vlemmings, a professor at the Chalmers University of Technology in Sweden. “Itistrulyexcitingtodirectlywitness,inapicture, watermoleculesbeingreleasedfromicydustpar- ticles,” saysElizabethHumphreys,anastronomer atESOwhoalsoparticipatedinthestudy.Thedust grainsthatmakeupadiscaretheseedsofplanet formation,collidingandclumpingintoeverlarger bodiesorbitingthestar.Astronomersbelievethat where it is cold enough for water to freeze onto dust particles, things stick together more effi- ciently—anidealspotforplanetformation. “Our results show how the presence of water may influ- encethedevelopmentofaplanetarysystem,just like it did some 4.5 billion years ago in our own Solar System,” Facchini adds. With upgrades happening at ALMA and ESO’s Extremely Large Telescope (ELT) coming online withinthedecade,planetformationandtherole waterplaysinitwillbecomeclearerthanever.In particularMETIS,theMid-infraredELTImagerand Spectrograph, will give astronomers unrivalled viewsoftheinnerregionsofplanet-formingdiscs, whereplanetslikeEarthform .     MAY-JUNE2024 إن ا ﺸﺎرﻛﺔ ﰲ ﻣﺜﻞ ﻫﺬا اﻻﻛﺘﺸﺎف ﰲ ﻗﺮص اﻟـﻨﺠﻢ HL Tauri اﻟﺸﻬ ﻛﺎن ﻳﻔﻮق ﻣﺎ ﻛﻨﺖ أﺗﻮﻗﻌﻪ ﰲ ﺗﺠﺮﺑ ﺘﻲ اﻟﺒﺤﺜﻴـﺔ اﻷوﱃ ﰲ " ﻋﻠﻢ اﻟﻔﻠﻚ ﻳﻀﻴﻒ ﻣـﺎﺗﻴﻮ ﻓﺎﻧـﺪردوﻧﻜﺖ ﻣـﻦ ﺟﺎﻣﻌـﺔ ﻟﻴـﻴﺞ ﺑﺒﻠﺠﻴﻜﺎ، واﻟﺬي ﻛﺎن ﻃﺎﻟﺐ ﻣﺎﺟﺴﺘ ﻋﻨﺪﻣﺎ ﺷﺎرك ﰲ اﻟﺒﺤـﺚ . ﻟﻘﺪ ﻋﺜﺮ ﻋﲆ ﻛﻤﻴﺔ ﻛﺒ ة ﻣﻦ ا ﻴﺎه ﰲ ا ﻨﻄﻘﺔ ﺣﻴﺚ ﺗﻮﺟﺪ ﻓﺠﻮة ﻣﻌﺮوﻓﺔ ﰲ اﻟﻨﺠﻢ .HL Tauri ﻳﺘﻢ ﻧﺤﺖ ﻓﺠﻮات ﻋﲆ ﺷﻜﻞ ﺣﻠﻘﺔ ﰲ ﺷﻜﻞ أﻗﺮاصﻏﻨﻴﺔ ﺑﺎﻟﻐﺒﺎر ﻋﻦ ﻃﺮﻳﻖ اﻟﺪوران ﺣﻮل أﺟﺴﺎم ﺷﺎﺑﺔ ﺗﺸـﺒﻪ اﻟﻜﻮاﻛـﺐ أﺛﻨـﺎء ﺟﻤﻌﻬﺎ ﻟﻠﻤﻮاد وﻧﻤﻮﻫﺎ . ﻳﻘﻮل ﻓﺎﺗﺸﻴﻨﻲ " : ﺗﻜﺸﻒ اﻟﺼﻮر اﻟﺤﺪ ﻳﺜﺔ ﻋﻦ ﻛﻤﻴﺔ ﻛﺒ ة ﻣـﻦ ﺑﺨﺎر ا ﺎء ﻋﲆ ﻣﺴﺎﻓﺎت ﺑﻌﻴﺪة ﻋﻦ اﻟﻨﺠﻢ، ﺑﻤـﺎ ﰲ ذﻟـﻚ ﻓﺠـﻮة ﻳﻤﻜﻦ أن ﻳﺘﺸﻜﻞ ﻓﻴﻬﺎ ﻛﻮﻛﺐ ﰲ اﻟﻮﻗﺖ اﻟﺤﺎﴐ ". ﻳﺸ ﻫﺬا إﱃ أن ﺑﺨﺎر ا ﺎء ﻫـﺬا ﻳﻤﻜـﻦ أن ﻳـﺆﺛﺮ ﻋـﲆ اﻟﱰﻛﻴـﺐ اﻟﻜﻴﻤﻴـﺎﺋﻲ ﻟﻠﻜﻮاﻛﺐ اﻟﺘﻲ ﺗﺘﺸﻜﻞ ﰲ ﺗﻠﻚ ا ﻨﺎﻃ .ﻖ إن رﺻﺪ ا ﻴﺎه ﺑﺎﺳﺘﺨﺪام ا ﻟﺘﻠﺴﻜﻮب اﻷرﴈ ﻟﻴﺲ ﺑﺎﻷﻣﺮ اﻟﻬـ ﺣﻴﺚ أن ﺑﺨﺎر ا ﺎء اﻟﻐﺰﻳﺮ ﰲ اﻟﻐﻼف اﻟﺠﻮي ﻟـﻸرض ﻳـﺆدي إﱃ ﺗﺪﻫﻮر اﻹﺷﺎرات اﻟﻔﻠﻜﻴﺔ . إن ﻣﺮﺻﺪ أ ﺎ ﺪﻳﺮه ﻳ ﺬياﻟ ا ﺮﺻﺪ اﻷوروﺑﻲ اﻟﺠﻨـﻮﺑﻲ ﺑﺎﻟﺘﻌـﺎون اﻟ ﻣﻊ ءﴩﻛﺎ اﻟﺪوﻟﻴ ﻋﺒﺎرة ﻋﻦ ﻣﺠﻤﻮﻋـﺔ ﻣـﻦ اﻟﺘﻠﺴـﻜﻮﺑﺎت ا ﻮﺟﻮدة ﰲ ﺻﺤﺮاء أﺗﺎﻛﺎﻣﺎ اﻟﺘﺸﻴﻠﻴﺔ ﻋﲆ ارﺗﻔﺎع ﺣـﻮاﱄ 5000 ﻣﱰ وﻗﺪ ﺗﻢ ﺑﻨﺎؤﻫﺎ ﰲ ﺑﻴﺌﺔ ﻋﺎﻟﻴﺔ وﺟﺎﻓﺔ ﺧﺼﻴﺼﺎً ﻟﺘﻘﻠﻴﻞ ﻫـﺬا اﻟﺘﺪﻫﻮر وﺗﻮﻓ ﻇﺮوف رﺻﺪ اﺳﺘﺜﻨﺎﺋﻴﺔ . ﻳ ﻘﻮل ا ﺆﻟﻒ ا ﺸﺎرك ﻓﻮﺗﺮ ﻓﻠﻴﻤﻨﺠﺰ واﻷﺳﺘﺎذ ﺑﺠﺎﻣﻌﺔ ﺗﺸﺎ ﺮز ﻟ ﻠﺘﻜﻨﻮﻟﻮﺟﻴﺎ ﰲ اﻟﺴﻮﻳﺪ " : ﺣﺘـﻰ اﻵن ﻳﻌـﺪ ﻣﺮﺻـﺪ أ ـﺎ اﻟﻮﺣ ﻴـﺪ اﻟﻘﺎدر ﻋﲆ ﺗﺤﻠﻴﻞ ا ﺎء ﰲ ﻗﺮص ﺑﺎرد ﻣﻜﻮ ن ﻟﻠﻜﻮﻛﺐ ." ﺗﻘﻮل إﻟﻴﺰاﺑﻴـﺚ ﻫﻤﻔﺮﻳـﺰ ﻋﺎ ـﺔ اﻟﻔﻠـﻚ ﰲ ا ﺮﺻـﺪ اﻻوروﺑـﻲ اﻟﺠﻨﻮﺑﻲ واﻟﺘﻲ ﺷﺎرﻛﺖ أﻳﻀ ﺎً ﰲ اﻟﺪراﺳﺔ " : اﻟﺮاﺋﻊ ﻣﻦ أن ﻧﺸﺎﻫﺪ ﻣﺒﺎﴍة ﰲ اﻟﺼﻮرة ﺟﺰﻳﺌﺎت ا ﺎء ﺗﻨﻄﻠﻖ ﻣـﻦ ﺟﺰﻳﺌـﺎت اﻟﻐﺒـﺎر اﻟﺠﻠﻴﺪي ." ﺗﻌﻤﻞ ﺣﺒﻴﺒﺎت اﻟﻐﺒﺎر اﻟﺘﻲ ﺗﺸﻜﻞ اﻟﻜﻮﻛﺐ ﻋـﲆ اﻟـﺘﺨﻠﺺ ﻣـﻦ ﺑﺬور ﺗﺸﻜﻞ اﻟﻜﻮﻛﺐ ﺘﻓﺘ ﺼﺎدم وﺗﺘﻜﺘﻞ ﻟﺘﺸﻜﻞ أﺟﺴـﺎﻣﺎ أﻛـﱪ ﺣﺠﻤ ﺎ ﺗﺪور ﺣﻮل اﻟﻨﺠﻢ . ً ﻳ ﻌﺘﻘﺪ أﻧﻪ ﻋﻨﺪﻣﺎ ﻳﻜﻮن اﻟﺠﻮ ﺑﺎردا ﺑﻤﺎ ﻓﻴﻪ اﻟﻜﻔﺎﻳﺔ ﻟﻴﺘﺠ ﻤﺪ ا ﺎء ﻋﲆ ﺷﻜﻞ ذرات ﻣﻦ اﻟﻐﺒﺎر ﻓﺈن اﻷ ﺷﻴﺎء ﺗﻠﺘﺼﻖ ﺑﺒﻌﻀﻬﺎ ﺑﻜﻔﺎءة أﻛﱪ وﻫﻮ ﻣﻜﺎن ﻣﺜﺎﱄ ﻟﺘﻜﻮﻳﻦ اﻟﻜﻮاﻛﺐ . ﻳﻀﻴﻒ ﻓﺎﺗﺸﻴﻨﻲ " : ﺗﻈﻬﺮ ﻧﺘﺎﺋﺠﻨﺎ ﺗﺄﺛ وﺟﻮد ا ﺎء ﻋﲆ ﺗﻄـ ﻮر اﻟﻨﻈﺎم اﻟﻜﻮﻛﺒﻲ ﻛﻤﺎ ﺣﺪث ﻗﺒﻞ ﺣﻮاﱄ 4.5 ﻣﻠﻴﺎر ﺳﻨﺔ ﰲ ﻧﻈﺎﻣﻨﺎ اﻟﺸﻤﴘ ." ﻣﻊ اﻟﺘﺤﺪﻳﺜﺎت اﻟﺘﻲ ﺳﺘﺤﺪث ﰲ ﻣﺮﺻﺪ أ ﺎ واﻟﺘﻠﺴﻜﻮب اﻟﻌﻤﻼق اﻟﺘﺎﺑﻊ ﻟﻠﻤﺮﺻﺪ اﻷوروﺑﻲ اﻟﺠﻨﻮﺑﻲ واﻟﺬي ﺳﻴﺒﺪأ اﻟﻌﻤﻞ ﺑﻪ ﰲ ﻫﺬا اﻟﻌﻘﺪ ﺳﻴﺼﺒﺢ ﺗﻜﻮﻳﻦ اﻟﻜﻮاﻛﺐ واﻟﺘﺪﻓﻘﺎت ا ﺎﺋﻴـﺔ ﻓﻴـﻪ أﻛﺜـﺮ وﺿﻮﺣًﺎ ﻣﺎ ﺳﻴﻮﻓﺮ ﺟﺪﻳﺪة ﻇﺮ ﻣﻨﺎ ﻟﻠﻤﻨﺎﻃﻖ اﻟﺪاﺧﻠﻴـﺔ ﻷﻗـﺮاص ﺗﻜﻮﻳﻦ اﻟﻜﻮ اﻛﺐ، ﺣﻴﺚ ﺗﺸﺒﻪ اﻟﻜﻮاﻛﺐ ﺷﻜﻞ اﻷرض . ﻣﺠﻠﺔ FreeAstronomy ﺎﻟﻌﺮ ﺔ ﻟﻘــﺪ ـــﮫ ﻤﻜــﻦ أن ﺗﺘﺸـــ ﻞ ﻓ ـــﺎن اﻟـــﺬ ــﻢﺷـــﺎب وﻫــﻮ اﻟﻤ وﺟـــﺪ ﻋﻠﻤـــﺎء اﻟﻔﻠــﻚ ﺑﺨـــﺎر ﻣــﺎء ﻣﺨﺘﺒﺌًـــﺎ ﺣـــﻮل ﻧ اﻟ ﻮاﻛﺐ ﺎﻟﻀ ﻂ . ﻓﻲ ﻫﺬﻩ اﻟﺼﻮرة، ﺗُﻈﻬﺮ اﻷرﺻﺎد ـاﻟ ـﺔ ﺠﺪ ﺪة ﻣﻦ ﻣﺼـﻔﻮﻓﺔ أﺗﺎ ﺎﻣـﺎ اﻟﻜﺒـ ة اﻟﻤﻠ ﻤ ﺗ/ ــﺔ ﺤــﺖ اﻟﻤﻠ ﻤ أﻟﻤـــﺎ ) ( ﻌـــﺪ ، واﻟــ اﻟﻤﺮﺻــﺪ اﻷوروﺑـــﻲ اﻟـــﺠﻨﻮﺑﻲ ﺎً ﺷــﺮ ﻓﻴﻬـــﺎ ﺑﺨــﺎراﻟﻤـــﺎء ﻈــﻼل ﻣـــﻦ اﻟﻠﻮن اﻷزرق . و ﺎﻟﻘﺮ ﻣﻦ ﻣﺮﻛﺰ اﻟﻘﺮصﺣ ﺚ ﻳﻮﺟﺪ اﻟﻨ ﻢ اﻟﺸﺎب ﺗ ﻮن اﻟﺒﻴﺌﺔ أﻛ ﺳـﺨﻮﻧﺔ واﻟﻐـﺎز أﻛـ ـاﻟ. ﺳﻄﻮﻋﺎً ﺤﻠﻘﺎت ذات اﻟﻠﻮن اﻷ ﻤﺮﻫﻲ أرﺻﺎد ﻣﺮﺻﺪ أﻟﻤﺎ اﻟ ﺴﺎ ﻘﺔ ﺗﻮﺿﺢ ﺗﻮز ﻊ اﻟﻐ ﺎرﺣﻮل اﻟﻨ .ﻢ ﻫﺬﻩ اﻟﺘﻘﻄﺘﻬﺎ ﻫﻲ اﻟﺼﻮرة اﻷﻛ وﺿﻮﺣًﺎ اﻟ ﻣﺮﺻﺪ أﻟﻤﺎ ﻋﻠﻰ اﻹﻃﻼق - وﻫﻲ أﻛـ وﺿـﻮﺣ ﺎ ﻣﻤـﺎ ﻓﻲ اﻟﻀﻮء اﻟﻤﺮﻲ ﺎﺳﺘﺨﺪام ﺗﻠﺴ ﻮبﻫﺎﺑﻞ اﻟﻔﻀﺎﺋﻲ اﻟﺘﺎﺑﻊ ﻟﻨﺎﺳﺎ وو ﺎﻟـﺔ ﺘﻢ ﺗﺤﻘ ﻘﮫ ﺸ ﻞ روﺗ اﻟﻔﻀﺎء اﻷوروﺑ ﺔ . ـﺎﻟﻨ ﻢ اﻷوﻟـﻲ اﻟﻤﺤـ ﻂ ـﻮﻛ ُﻈﻬﺮ اﻟﻘﺮص اﻟ اﻟﺸـﺎب HL Tauri . ـﺎت ﺗﻜﺸـﻒﻋﻤﻠ رﺻــﺪ ﻣﺮﺻــﺪ أﻟﻤـﺎ ـ اﻟــ ــﺔ د ﺗﺤﺘ ــ ﺠﺪ ﺪة ﻋــﻦ اﺧــﻞ اﻟﻘــﺮص ﻟـﻢ ﺴـﺒﻖ رؤ ﺘﻬـﺎ ﻣــﻦ ﻗﺒـﻞ ﻤـﺎ ﺗُﻈﻬــﺮاﻟﻤﻮاﻗــﻊ ﺗﺘﺸ ﻞ ﻓﻲ اﻟ ﻘﻊ اﻟﻤﻈﻠﻤﺔ داﺧﻞ اﻟﻨﻈﺎم اﻟﻤﺤﺘﻤﻠﺔ ﻟﻠ ﻮاﻛﺐ اﻟ . - ﻣﺎﻳﻮ ﻳﻮﻧﻴﻮ 2 0 2 4