Free Astronomy Magazine July-August 2025 ARABIC VERSION

detectedwatericewithWebb,they have opened the door for allre- searchers to study how these processes play out in new ways in many other planetary systems. The star, cataloged HD 181327, is significantly younger than our Sun. It’s estimated to be 23 million years old, compared to the Sun’s more mature 4.6 billion years. The star is slightly more massive than the Sun, and it’s hotter, which led to the for- mation of a slightly larger system around it. Webb’s observations confirm a sig- nificant gap between the star and itsdebrisdisk—awideareathatis freeofdust.Fartherout,itsdebris disk is similar to our solar system’s Kuiper Belt, where dwarf planets, comets, and other bits of ice and rockarefound(andsometimescol- lide with one another). Billions of yearsago,ourKuiperBeltwaslikely similar to this star’s debris disk. “HD181327isaveryactivesystem,” Chensaid. “Thereareregular,ongo- ingcollisionsinitsdebrisdisk.When thoseicybodiescollide,theyrelease tinyparticlesofdustywatericethat areperfectlysizedforWebbtode- tect.” Water ice isn’t spread evenly throughoutthissystem.Themajor- ity is found where it’s coldest and farthest from the star. “The outer area of the debris disk consists of over 20% water ice,” Xie said. Thecloserintheresearcherslooked, the less water ice they found. To- ward the middle of the debris disk, Webb detected about 8% water ice. Here, it’s likely that frozen water particlesareproducedslightlyfaster than they are destroyed. In the area of the debris disk closest to the star, Webb detected almost none.It’slikelythatthestar’sultra- violet light vaporizes the closest specksofwaterice.It’salsopossible that rocks known as planetesimals have “locked up” frozen water in their interiors, which Webb can’t detect. This team and many more re- searchers will continueto search for — and study — water ice in debris disksandactivelyformingplanetary systems throughout our Milky Way galaxy. “The presence of water ice helpsfacilitateplanetformation,” Xiesaid. “Icymaterialsmayalsoul- timatelybe‘delivered’toterrestrial planetsthatmayformoveracouple hundred million years in systems likethis.” Theresearchersobserved HD 181327 with Webb’s NIRSpec (Near-InfraredSpectrograph),which issuper-sensitivetoextremelyfaint dust particles that can only be de- tectedfromspace.                           JULY-AUGUST2025 ﻷول ﻣــــﺮة ـــــﺪ ﻣـــــﺎﺋﻲ ـــــﺎﺣﺜﻮن وﺟـــــﻮد ﺟﻠ أﻛـــــﺪ ﻠـــﻮريﻓـــﻲﻗـــﺮصﺣﻄــــﺎم ـــﺪورﺣــــﻮل ـــﺎري ﻏ ــــــــــﻢﺷـــــــــــﺒ ﮫ ﺎﻟﺸـــــــــــﻤﺲ ﻧ وذﻟـــــــــــﻚ ﺎﺳـــــــــــﺘﺨﺪام ﺗﻠﺴ ﻮب ﺟ ﻤﺲ و ﺐ اﻟﻔﻀـﺎﺋﻲ اﻟﺘـﺎﺑﻊ ﻟ ﻮ ﺎﻟـﺔ ﻧﺎﺳــــﺎ . رﺻـــــﺪﻫﺎ ـــــﺎﻩ اﻟﻤﺘ ﻤــــﺪة اﻟــــ ﻤﻴــــﻊ اﻟﻤ ﺗﻠﺴــــ ﻮب ــــﺎ ــــﺔ ﺑﺠﺰ ﺌــــﺎت ﻏ ــــﺐ ﻣﻘ و ردﻗ ﻘــــﺔ ﻣﻮزﻋـــــﮫ ﻓـــــﻲ أﻧﺤــــــﺎء اﻟﻘـــــﺮص . ﻣﻌﻈـــــﻢ اﻟــــــ ـ ﺠﻠ ﺪ اﻟﻤــــ ﺎﺋﻲ ـــــﺎردة ـــــﺪة اﻟ ﻓـــــﻲ اﻟﻤﻨـــــﺎﻃﻖ اﻟ ﻌ ﻋـــــﻦ اﻟﻨ ﻢ . اﻟ ﺎﺣﺜﻮن ﻣﻦ ﻠﻤﺎ اﻗ اﻟـﻨ ﻢ ﺗﻨـﺎﻗﺺ ـاﻟ ﺠﻠ ﺪ اﻟﻤﺎﺋﻲ ﺸ ﻞ ﻣﻠﺤﻮظ اﺧﺘﻔﻰ ﺣ . [NASA, ESA, CSA, STScI, Ralf Crawford (STScI)] ﺑﻌ واﻵن ﺪ أن اﻛﺘﺸﻒ اﻟﺒﺎﺣﺜﻮن اﻟﺠﻠﻴﺪ ا ـﺎﺋﻲ ﺑﺎﺳﺘﺨﺪام ﺗﻠﺴﻜﻮب وﻳﺐ، ﻓﻘﺪ ﻓﺘﺤﻮا اﻟﺒـﺎب أﻣﺎم ﺟﻤﻴﻊ اﻟﺒﺎﺣﺜ ﻟﺪراﺳﺔ ﻛﻴﻔﻴـﺔ ﺗﻄـﻮر ﻫﺬه اﻟﻌﻤﻠﻴﺎت ﺑﻄﺮق ﺟﺪﻳـﺪة ﰲ اﻟﻌﺪﻳـﺪ ﻣـﻦ اﻷﻧﻈﻤﺔ اﻟﻜﻮﻛﺒﻴﺔ اﻷﺧﺮى . اﻟـﻨﺠﻢ ا ﺼـﻨﻒ HD 181327 أﺻـﻐﺮ ﺳـﻨ ﺎً ﺑﻜﺜ اﻟﺸﻤﺲ ﻣﻦ ﻳ. ﻘﺪر ﻋﻤﺮه ﺑـ 23 ﻣﻠﻴﻮن ﺳﻨﺔ ﻣﻘﺎرﻧﺔً ﺑﻌ ﻤﺮ اﻟﺸـﻤﺲ اﻷﻛﺜـﺮ ﻧﻀـﺠ ﺎً واﻟﺬي ﻳﺒﻠﻎ 4.6 ﻣﻠﻴﺎر . ﺳـﻨﺔ اﻟـﻨﺠﻢ أﺿـﺨﻢ ﻗﻠﻴﻼً ﻣﻦ اﻟﺸﻤﺲ وﻫﻮ أﻛﺜﺮ ﺳﺨﻮﻧﺔ ﻣﻤﺎ أدى إﱃ ﺗﻜﻮﻳﻦ ﻧﻈﺎم أﻛﱪ ﻗﻠﻴﻼً ﺣﻮﻟﻪ . ﺗﺆﻛﺪ أرﺻﺎد ﺗﻠﺴـﻜﻮب وﻳـﺐ وﺟـﻮد ﻓ ﺠـﻮة ﻛﺒ ة ﺑ اﻟﻨﺠﻢ وﻗﺮص ﺣﻄﺎﻣﻪ أي ﻣﺴﺎﺣﺔ واﺳﻌﺔ ﺧﺎﻟﻴﺔ ﻣﻦ اﻟﻐﺒﺎر . أﺑﻌﺪ ﻣﻦ ذﻟﻚ ﻳﺸﺒﻪ ﻗ ـﺮصﺣﻄﺎﻣ ـﻪ ﺣ ـﺰام ﻛ ـ ﺎﻳﱪ ﰲ ﻧﻈﺎﻣﻨ ـﺎ اﻟﺸـ ﻤﴘـ ﺣﻴـﺚ ﺗﻮﺟـﺪ اﻟﻜﻮاﻛـﺐ اﻟﻘﺰﻣـﺔ وا ﺬﻧﺒﺎت وﻗﻄﻊ أﺧﺮى ﻣﻦ اﻟﺠﻠﻴﺪ واﻟﺼﺨﻮر ﺎً وأﺣﻴﺎﻧ ) ﺗﺼﻄﺪم ﺑﺒﻌﻀـﻬﺎ .( ﻣﻨـﺬ ﻣﻠﻴـﺎرات اﻟﺴﻨ ﻛﺎن ﺣﺰام ﻛﺎﻳﱪ اﻟﺨﺎص ﺑﻨﺎ ﻣﺸـﺎﺑﻬ ﺎً ﻋﲆ اﻷرﺟﺢ ﻟﻘﺮصﺣﻄﺎم ﻫﺬا اﻟﻨﺠﻢ . ﻗــﺎل ﺗﺸــ " : HD181327 ﻧﻈــﺎم ﺷــﺪﻳﺪ اﻟﻨﺸﺎط ﺣﻴـﺚ ﺗﺤـﺪث ﺗﺼـﺎدﻣﺎت ﻣﻨﺘﻈﻤـﺔ وﻣﺴﺘﻤﺮة ﰲ ﻗﺮص ﺣﻄﺎﻣﻪ . ﻋﻨﺪﻣﺎ ﺗﺼـﻄﺪم ـــــــــــــــــــــــــــــــــــــ ﻫﺬه اﻷﺟﺴﺎم اﻟﺠﻠﻴﺪﻳﺔ ﺗُﻄﻠﻖ ﺟﺰﻳﺌﺎت دﻗﻴﻘﺔ ﺟﻠﻴﺪ ﻣﻦ ا ﺎء اﻟﻐﺒﺎري ﺑﺤﺠﻢ ﻣﺜﺎﱄ ﻟ ﺻـﺪه ﺗﻠﺴﻜﻮب . وﻳﺐ ﻻ ﻳﻨﺘﴩﺟﻠﻴﺪ ا ﺎء ﺑﺎ ﻟﺘﺴﺎوي ﰲ ﺟﻤﻴﻊ أﻧﺤﺎء ﻫﺬا اﻟﻨﻈﺎم إذ ﺗﻮﺟﺪ ﻏﺎﻟﺒﻴﺘـﻪ ﰲ ا ﻨﺎﻃﻖ اﻷﺑﺮد واﻷﺑﻌﺪ ﻋﻦ اﻟﻨﺠﻢ . ﻗـﺎل ﳾ : " ﺗﺘﻜـﻮن ا ﻨﻄﻘ ـﺔ اﻟﺨﺎرﺟﻴ ـﺔ ﻣ ـﻦ ﻗ ـﺮص اﻟﺤﻄﺎم ﻣﻦ أﻛﺜﺮ ﻣﻦ 20 % ﻣﻦ ﺟﻠﻴـﺪ ا ـﺎء ." ﻛﻠﻤﺎ دﻗﻖ اﻟﺒﺎﺣﺜﻮن اﻟﻨﻈﺮ ﻗﻠّﺖ ﻛﻤﻴـﺔ ﺟﻠﻴـﺪ ا ﺎء ا ﻟﺘﻲ وﺟﺪوﻫﺎ . ﰲ ﻣﻨﺘﺼﻒ ﻗﺮص اﻟﺤﻄﺎم رﺻﺪ ﺗﻠﺴﻜﻮب وﻳﺐ ﺣﻮاﱄ 8 % ﻣﻦ ﺟﻠﻴﺪ ا ﺎء . ﻫﻨﺎ، ﻣﻦ ا ﺮﺟﺢ أن ﺟﺰﻳﺌـﺎت ا ـﺎء ا ﺘﺠﻤـﺪة ﺗُﻨﺘﺞ أﴎع ﻗﻠﻴﻼً ﻣـﻦ ﺗـﺪﻣ ﻫﺎ . ﰲ ﻣﻨ ﻄﻘـﺔ ﻗﺮص اﻟﺤﻄﺎم اﻷﻗﺮب إﱃ اﻟـﻨﺠﻢ ﻟـﻢ ﻳﺮﺻـﺪ ﺗﻠﺴﻜﻮب وﻳﺐ أي ﳾء ﺗﻘﺮﻳﺒ و ﺎً ﻣﻦ ا ـﺮﺟﺢ أن ﺿﻮء اﻟﻨﺠﻢ ﻓﻮق اﻟﺒﻨﻔﺴﺠﻲ ﻳﺒﺨﺮ أﻗـﺮب ﺑﻘﻊ اﻟﺠﻠﻴﺪ ا ﺎﺋﻲ وﻳﺤﺘﻤـﻞ أﻳﻀـ ﺎً أن ﺗﻜـﻮن اﻟﺼﺨﻮر ا ﻌﺮوﻓﺔ ﺑﺎﺳﻢ اﻟﻜﻮاﻛﺐ اﻟﺼﻐ ة ﻗﺪ " ﺣﺒﺴﺖ " ا ﺎء ا ﺘﺠﻤﺪ ﰲ أﺣﺸﺎﺋﻬ ﺎ وﻫﻮ ﻣﺎ ﻻ ﻳﺴﺘﻄﻴﻊ ﺗﻠﺴﻜﻮب وﻳﺐ رﺻﺪه . ﺳﻴﻮاﺻﻞ ﻫﺬا اﻟﻔﺮﻳﻖ واﻟﻌﺪﻳﺪ ﻣـﻦ اﻟﺒـﺎﺣﺜ اﻵﺧﺮﻳﻦ اﻟﺒﺤﺚ ﻋﻦ اﻟﺠﻠﻴﺪ ا ﺎﺋﻲ ودراﺳﺘﻪ ﰲ أﻗﺮاص اﻟﺤﻄﺎ م وﰲ اﻷﻧﻈﻤﺔ اﻟﻜﻮﻛﺒﻴـﺔ اﻟﺘـﻲ ﺗُﺸﻜّﻞ ﺑﻨﺸﺎط ﰲ ﺟﻤﻴﻊ أﻧﺤﺎء ﻣﺠﺮﺗﻨـﺎ درب اﻟﺘﺒﺎﻧﺔ ﻟﻔﻬﻢ أﺻﻮل ا ﻴﺎه ﺑﺸﻜﻞ أﻓﻀﻞ . ﻗﺎل ﺷﻴﺲ " : إن وﺟﻮد اﻟﺠﻠﻴﺪ ا ﺎﺋﻲ ﻳﺴﺎﻋﺪ ﰲ ﺗﺴﻬﻴﻞ ﺗﻜﻮﻳﻦ اﻟ ". ﻜﻮاﻛﺐ ﻗﺪ ﻳﺘﻢ ﺗﻮﺻﻴﻞ ا ﻮاد اﻟﺠﻠﻴﺪﻳـﺔ ﰲ اﻟﻨﻬﺎﻳـﺔ إﱃ اﻟﻜﻮاﻛﺐ اﻷرﺿﻴﺔ اﻟﺘﻲ ﻗﺪ ﺗﺘﺸﻜﻞ ﻋﲆ ﻣـﺪى ﻼﻳ ﻣﺌﺎت ا ﻣﻦ اﻟﺴﻨ ﰲ أﻧﻈﻤﺔ ﻣﺜﻞ ﻫﺬا ." ﻟ ﻘﺪ رﺻﺪ اﻟﺒﺎﺣﺜﻮن HD 181327 ﺑﺎﺳﺘﺨﺪام ﻣﻄﻴــﺎف اﻷﺷـﻌﺔ ﺗﺤــﺖ اﻟﺤﻤـﺮاء اﻟﻘﺮﻳـﺐ ) ﻧ ﺳﺒﻴﻚ ( اﻟﺘﺎﺑﻊ ﻟ ﺘﻠﺴﻜﻮب وﻳﺐ وﻫﻮ ﻓﺎﺋﻖ اﻟﺤﺴﺎﺳﻴﺔ ﻟﺠﺰﻳﺌﺎت اﻟﻐﺒﺎر اﻟﺨﺎﻓﺘﺔ اﻟﺘﻲ ﺟﺪاً ﻻ ﻳﻤﻜﻦ اﻛﺘﺸﺎﻓﻬﺎ إﻻ ﻣـﻦ اﻟﻔﻀـﺎء ﺑﻔﻀـﻞ ﺗﻘﻨﻴﺎﺗﻪ ا ﺘﻘﺪﻣﺔ واﻟﺮاﺋﺪة . ﻳﻮﻟﻴﻮ - ﺃﻏﺴﻄ ﺲ 2 0 2 5