Free Astronomy Magazine January-February 2024 ARABIC VERSION

forming regions of disks in the Lob- ster Nebula using the Medium Res- olution Spectrometer on Webb’s Mid-Infrared Instrument (MIRI). This first result focuses on the protoplan- etary disk termed XUE 1, which is lo- cated in the star cluster Pismis 24. “Only the MIRI wavelength range and spectral resolution allow us to probe the molecular inventory and physical conditions of the warm gas and dust where rocky planets form,” added team member Arjan Bik of Stockholm University in Sweden. Due to its location near several mas- sive stars in NGC 6357, scientists ex- pect XUE 1 to have been constantly exposed to high amounts of ultravi- olet radiation throughout its life. However, in this extreme environ- ment the team still detected a range of molecules that are the building blocks for terrestrial planets. “We find that the inner disk around XUE 1 is remarkably similar to those in nearby star-forming regions,” said team member Rens Waters of Rad- boud University in the Netherlands. “We’ve detected water and other molecules like carbon monoxide, carbon dioxide, hydrogen cyanide and acetylene. However, the emis- sion found was weaker than some models predicted. This might imply a small outer disk radius.” “We were surprised and excited because this is the first time that these molecules have been detected under these extreme conditions,” added Lars Cuijpers of Radboud Uni- versity. The team also found small, partially crystalline silicate dust at the disk’s surface. This is considered to be the building blocks of rocky planets. These results are good news for rocky planet formation, as the sci- ence team finds that the conditions in the inner disk resemble those found in the well-studied disks lo- cated in nearby star-forming re- gions, where only low-mass stars form. This suggests that rocky plan- ets can form in a much broader range of environments than previ- ously believed. The team notes that the remaining observations from the XUE program are crucial to establish the common- ality of these conditions. “XUE 1 shows us that the conditions to form rocky planets are there, so the next step is to check how com- mon that is,” says Ramírez-Tannus. “We will observe other disks in the same region to determine the fre- quency with which these conditions can be observed.”    JANUARY-FEBRUARY 2024 ﻣﺠﻠﺔ FreeAstronomy ﺎﻟﻌﺮ ﺔ 43 اﻟﻜﻮاﻛﺐ ﰲ ﺳﺪﻳﻢ ﺟـﺮاد اﻟﺒﺤـﺮ ﺑﺎﺳـﺘﺨﺪام ﻣﻄﻴﺎف اﻟﺪﻗﺔ ا ﺘﻮﺳـﻄﺔ ا ﻮﺟـﻮد ﻋـﲆ أداة اﻷﺷﻌﺔ ﺗﺤﺖ اﻟﺤﻤﺮاء ا ﺘﻮﺳـﻄﺔ ( ﻣـ ي ) اﻟﺨ ﺎﺻﺔ ﺑﺘﻠﺴﻜﻮب .ﺐوﻳ ﺗﺮﻛﺰ ﻫﺬه اﻟﻨﺘﻴﺠﺔ اﻷوﱃ ﻋﲆ اﻟﻘـﺮص اﻟﻜـﻮﻛﺒﻲ اﻷوﱄ ا ﺴـﻤﻰ ﺷﻮي ) 1( واﻟﺬي ﻳﻮﺟﺪ ﰲ اﻟﻌﻨﻘـﻮد اﻟﻨﺠﻤـﻲ ﺑﺴـﻤﻴﺲ .24 إن" ﻧﻄـﺎق اﻟﻄـﻮل ا ـﻮﺟﻲ ـــــ ﻟﻜﺎﻣ ا ( ﻣ ي ) واﻟﺪﻗﺔ اﻟﻄﻴﻔﻴﺔ ﺗﺴﻤﺢ ﻟﻨـﺎ ﺑﻔﺤــﺺ ا ﺨــﺰون اﻟﺠﺰﻳﺌــﻲ واﻟﻈــﺮوف اﻟﻔﻴﺰﻳﺎﺋﻴﺔ ﻟﻠﻐﺎز اﻟﺪاﻓﺊ واﻟﻐﺒﺎر ﺣﻴﺚ ﺗﺘﺸﻜﻞ اﻟﻜ ﻮاﻛﺐ اﻟﺼﺨﺮﻳﺔ ". أﺿﺎف ﻋﻀـﻮ اﻟﻔﺮﻳـﻖ أرﺟـﺎن ﺑﻴــﻚ ﻣــﻦ ﺟﺎﻣﻌــﺔ ﺳ ـﺘﻮﻛﻬﻮﻟﻢ ﰲ اﻟﺴﻮﻳﺪ . اً ﻧﻈﺮ ﻮﻗﻌﻪ ﺑﺎﻟﻘﺮب ﻣﻦ اﻟﻌﺪﻳﺪ ﻣﻦ اﻟﻨﺠـﻮم اﻟﻀـﺨﻤﺔ ﰲ NGC 6357 ، ﻳﺘﻮﻗـﻊ ـــــ اﻟﻌﻠﻤــﺎء أن ) ﺷـﻮي 1( ﺗﻌـﺮض ﺑﺎﺳـﺘﻤﺮار ﻟﻜﻤﻴﺎت ﻋﺎﻟﻴﺔ ﻣﻦ اﻷﺷﻌﺔ ﻓﻮق اﻟﺒﻨﻔﺴـﺠﻴﺔ ﻃـﻮال ﺣﻴﺎﺗ ـﻪ وﻣـﻊ ذﻟ ـﻚ ﰲ ﻫـﺬه اﻟﺒﻴﺌ ـﺔ اﻟﻘ ﺎﺳﻴﺔ، ﻻ ﻳﺰال اﻟﻔﺮﻳﻖ ﻳﻜﺘﺸﻒ ﻣﺠﻤﻮﻋـﺔ ﻣﻦ اﻟﺠﺰﻳﺌﺎت اﻟﺘﻲ ﺗﺸﻜﻞ اﻟﻠ ﺒﻨﺎت اﻷﺳﺎﺳﻴﺔ ﻟﻠﻜﻮاﻛﺐ اﻷرﺿﻴﺔ . ﻗﺎل ﻋﻀﻮ اﻟﻔﺮﻳﻖ رﻳـﻨﺲ ووﺗﺮز ﻣﻦ ﺟﺎﻣﻌﺔ رادﺑـﻮد ﰲ ﻫﻮﻟﻨـﺪا " : ﻟﻘـﺪ وﺟﺪﻧﺎ أن اﻟﻘﺮص اﻟﺪاﺧﲇ ﺣـﻮل ) ﺷـﻮي 1( ﻳﺸﺒﻪ ﺑﺸﻜﻞ ﻣﻠﺤﻮظ ﺗﻠﻚ ا ﻮﺟﻮدة ﰲ ﻣﻨﺎﻃﻖ ﺗﺸﻜﻞ اﻟﻨﺠﻮم اﻟﻘﺮﻳﺒﺔ " ." ﻟﻘﺪ اﻛﺘﺸﻔﻨﺎ ا ـﺎء وﺟﺰﻳﺌﺎت أﺧﺮى ﻣﺜـﻞ أول أﻛﺴـﻴﺪ اﻟﻜﺮﺑـﻮن وﺛﺎﻧﻲ أﻛﺴﻴﺪ اﻟﻜﺮﺑﻮن وﺳﻴﺎﻧﻴﺪ اﻟﻬﻴﺪروﺟ واﻷﺳﻴﺘﻴﻠ . وﻣﻊ ذﻟﻚ، ﻓﺈن اﻻﻧﺒﻌﺎﺛﺎت اﻟﺘـﻲ ﺗﻢ اﻟﻌﺜﻮر ﻋﻠﻴﻬﺎ ﻛﺎﻧﺖ أﺿﻌﻒ ﻣﻤﺎ ﺗﻨﺒﺄت ﺑﻪ ﺑﻌﺾ اﻟﻨﻤﺎذج . ﻗﺪ ﻳﻌﻨﻲ ﻫﺬا وﺟـﻮد ﻧﺼـﻒ ﻗﻄﺮ ﺧﺎرﺟﻲ ﺻﻐ ﻟﻠﻘﺮص . وأﺿﺎف ﻻرس ﻛﻮﻳﺠﱪز ﻣﻦ ﺟﺎﻣﻌﺔ رادﺑـﻮد : ﻟﻘ" ﺪ ﻓﻮﺟﺌﻨﺎ وﺷﻌﺮﻧﺎ ﺑﺎﻹﺛﺎرة ﻷن ﻫﺬه ﻫـﻲ ا ﺮة اﻷوﱃ اﻟﺘـﻲ ﻳـﺘﻢ ﻓﻴﻬـﺎ اﻛﺘﺸـﺎف ﻫـﺬه اﻟﺠﺰﻳﺌﺎت ﰲ ﻇﻞ ﻫﺬه اﻟﻈـﺮ وف اﻟﻘﺎﺳـﻴﺔ ." ﻛﻤﺎ ﻋﺜﺮ اﻟﻔﺮﻳﻖ أﻳﻀ ﺎً ﻋﲆ ﻏﺒـ ﺎر ﺳـﻴﻠﻴﻜﺎت ﺻﻐ ﻣﺘﺒﻠﻮر ﺟﺰﺋﻴ ﺎً ﻋـﲆ ﺳـﻄﺢ اﻟﻘـﺮص . ﻳﻌﺘﱪ ﻫﺬا ﺑﻤﺜﺎﺑﺔ اﻟﻠﺒﻨﺎت اﻷﺳﺎﺳﻴﺔ ﻟﻠﻜﻮاﻛﺐ اﻟﺼﺨﺮﻳﺔ . ﺗﻌﺪ ﻫﺬه اﻟﻨﺘﺎﺋﺞ أﺧﺒﺎر اً ﺟﻴـﺪة ﻓﻴ ﻤـﺎ ﻳﺘﻌﻠـﻖ ﺑﺘﻜـﻮﻳﻦ اﻟﻜﻮاﻛـﺐ اﻟﺼـﺨﺮﻳﺔ ﺣﻴـﺚ وﺟـﺪ اﻟﻔﺮﻳـﻖ اﻟﻌﻠﻤـﻲ أن اﻟﻈـﺮوف ا ﻮﺟـﻮدة ﰲ اﻟﻘـﺮص اﻟـﺪاﺧﲇ ﺗﺸـﺒﻪ ﺗﻠـﻚ ا ﻮﺟـﻮدة ﰲ اﻷﻗﺮاص ا ﺪروﺳﺔ ﺟﻴﺪًا واﻟﻮاﻗﻌ ﺔ ﰲ ﻣﻨﺎﻃﻖ ﺗﻜﻮﻳﻦ اﻟﻨﺠﻮم اﻟﻘﺮﻳﺒﺔ ﻳ ﺣﻴﺚ ﻻ ﻮﺟـﺪ ﺳـﻮى ﻛﺘﻞ ﻣﻨﺨﻔﻀﺔ ﻓﻘﻂ . ﺗﺸﻜﻞ اﻟﻨﺠﻮم . وﻳﺸ ﻫـﺬا إﱃ أن اﻟﻜﻮاﻛ ـﺐ اﻟﺼـﺨﺮﻳ ﺔ ﻳﻤﻜ ـﻦ أن ﺗﺘﺸﻜﻞ ﰲ ﻧﻄﺎق ﺑﻴﺌﺎت أوﺳﻊ ﺑﻜﺜ ﻣﻤﺎ ﻛﺎن ﻳﻌﺘﻘﺪ ﺳﺎﺑﻘﺎ . ﻳﺸ اﻟﻔﺮﻳـﻖ إﱃ أن اﻷرﺻـﺎد ا ﺘﺒﻘﻴـﺔ ﻣـﻦ ﺑﺮﻧﺎﻣﺞ (ﺷﻮي ) ﴐورﻳﺔ ﻟﺘﺤﺪﻳﺪ اﻟﻘﻮاﺳـﻢ ا ﺸﱰﻛﺔ ﺑ ﻫﺬه اﻟﺤﺎﻻت . ﻳﻘﻮل راﻣ ﻳـﺰ - ﺗﺎﻧﻮس " : ﻳُﻈﻬﺮ ﻟﻨﺎ ) ﺷـﻮي 1( أن اﻟﻈـﺮوف اﻟﻼزﻣﺔ ﻟﺘﺸﻜﻞ اﻟﻜﻮاﻛﺐ اﻟﺼﺨﺮﻳﺔ ﻣﻮﺟﻮدة ﻟﺬا ﻓﺈن اﻟﺨﻄﻮة اﻟﺘﺎﻟ ﻴﺔ ﻫﻲ اﻟﺘﺤﻘﻖ ﻣﻦ ﻣﺪى ". ﺷﻴﻮع ذﻟﻚ ﺳﻨﺮاﻗﺐ اﻷﻗﺮاص اﻷﺧﺮى ﰲ ﻧﻔﺲ ا ﻨﻄﻘـﺔ ﻟﺘﺤﺪﻳﺪ اﻟﱰدد اﻟﺬي ﻳﻤﻜﻦ ﻣﻦ ﺧﻼﻟـﻪ رﺻـﺪ ﻫﺬه اﻟﻈﺮوف ." - ﻳﻨﺎﻳﺮ ﻓﺒﺮﺍﻳﺮ 2 0 2 4 رﺳﻢ ﺗﺨ ﻠﻲ ﻈﻬﺮ ﻧ ﻢﺷـﺎب ﻣﺤـﺎط ﻘـﺮص أوﻟﻲ ﺗﺘﺸ ﻞ ﻓ ﮫ اﻟ ﻮاﻛﺐ ﻮﻛ ] . ESO [