Free Astronomy Magazine September-October 2025 ARABIC VERSION

with conventional methods. No- tably,thesedistinctivesubstructures werefoundforasignificantnumber of stars in their early formation stages, approximately several hun- dred thousand years after the star birth.Thissuggeststhepossibleco- evolution of stars and planets in a gasanddustrichenvironment,pro- viding an important clue to under- standing the process of planet formation. Identifying the formation period of planetarysystems,suchasourSolar System, could be the beginning of thejourneytodiscovertheoriginof life. The key to this is the unique substructures found in protoplane- tary disks – the sites of planet for- mation. A protoplanetary disk is composed of low-temperature mo- lecular gas and dust, surrounding a protostar.Ifaplanetexistsinthe disk, its gravity will gather or eject materials within the disk, forming characteristic substructures such as rings or spirals. In other words, var- ious disk substructures can be inter- preted as “messages” from the forming planets. To study these sub- structures in detail, high-resolution radio observations with ALMA are required. Numerous ALMA observations of protoplanetarydisks(orcircumstel- lar disks) have been conducted so far. In particular, two ALMA large programs, DSHARP and eDisk, have revealed the detailed distribution of dust in protoplanetary disks through high-resolution observa- tions. The DSHARP project discov- eredthatdistinctivestructuresare common in circumstellar disks around 20 young stars, each exceed- ing one millionyears sincethe onset of star formation. On the other hand, fewer distinctive structures were found by the eDisk project that investigated disks around 19 protostars in the accretion phase (the stage where mass accretion ontothestarandthediskisactive). This phase occurs approximately 10,000 to 100,000 years after star birth. This suggests that disks have diverse characteristics depending on the age of the star. Here, the question is when do sub- structures, the signs of planet for- mation, appear in disks. To find the answer, it is necessary to observe disks of a wide range of intermedi- ate ages that have yet to be ex- plored. However, limitations on the number of disks observable at high resolution, due to distance and ob- servational time, make it challeng- ingtoconductastatisticallysig- ﻣﺠﻠﺔ FreeAstronomy ﺎﻟﻌﺮ ﺔ 32 اﻟﺠﺪﻳﺮ ﺑﺎﻟﺬﻛﺮ أن ﻫﺬه ا ﻟ ﻬﻴﺎﻛﻞ ا ﻤﻴـﺰة ﻋ ﺜـﺮ ﻋﻠﻴﻬـ ﺎ ﻟﻌـﺪد ﻛﺒـ ﻣـﻦ اﻟﻨﺠـﻮم ﰲ ﻣﺮاﺣـﻞ ﺗﻜﻮﻳﻨﻬﺎ ا ﺒﻜـﺮة أي ﺑﻌـﺪ ﻣﺌـﺎت اﻵﻻف ﻣـ ﻦ اﻟﺴﻨ ﺗﻘﺮﻳﺒﺎً ﻣﻦ وﻻدة اﻟﻨﺠﻢ وﻳﺸ ﻫﺬا إﱃ اﻟﺘﻄﻮر ا ﺸﱰك ا ﺤﺘﻤﻞ ﻟﻠﻨﺠﻮم واﻟﻜﻮاﻛﺐ ﰲ ﺑﻴﺌﺔ ﻏﺎزﻳﺔ وﻏﺒﺎرﻳﺔ ﻣﻤﺎ ﻳـﻮﻓﺮ دﻟـﻴﻼً ﻣﻬﻤـﺎً ﻟﻔﻬﻢ ﻋﻤﻠﻴﺔ ﺗﻜﻮﻳﻦ اﻟﻜﻮاﻛﺐ . ﻗــﺪ ﻳﻜـﻮن ﺗﺤﺪﻳـﺪ ﻓـﱰة ﺗﻜـﻮﻳﻦ اﻷﻧ ﻈﻤـﺔ اﻟﻜﻮﻛﺒﻴﺔ ﻣﺜﻞ ﻧﻈﺎﻣﻨﺎ اﻟﺸﻤﴘ ﺑﺪاﻳـﺔ رﺣﻠـﺔ اﻛﺘﺸﺎف أﺻﻞ اﻟﺤﻴﺎة . ﻳﻜﻤﻦ ﻣﻔﺘـﺎح ذﻟـﻚ ﰲ اﻟﺒﻨﻰ اﻟﺘﺤﺘﻴﺔ اﻟﻔﺮﻳﺪة ا ﻮﺟﻮ دة ﰲ اﻷﻗـﺮاص اﻟﻜﻮﻛﺒﻴﺔ اﻷوﻟﻴﺔ ﻣﻮاﻗﻊ ﺗﻜﻮﻳﻦ اﻟﻜﻮاﻛﺐ . ﻳﺘﻜﻮن اﻟﻘﺮص اﻟﻜﻮﻛﺒﻲ اﻷوﱄ ﻣ ﻦ ﻏﺎز وﻏﺒﺎر ﺟﺰﻳﺌﻲ ﻣﻨﺨﻔﺾ اﻟﺤﺮارة ﻳﺤﻴﻂ ﺑﺎﻟﻨﺠﻢ اﻷوﱄ وإذا وﺟﺪ ﻛﻮﻛﺐ ﰲ اﻟﻘـ ﺮص ﻓـﺈن ﺟﺎذﺑﻴﺘـﻪ ﺳﺘﺠﻤﻊ أو ﺗﻘﺬف ا ﻮاد داﺧﻞ اﻟﻘﺮص ﻣﻜﻮﻧﺔً ﺑﻨــﻰ ﻓﺮﻋﻴــﺔ ﻣﻤﻴــﺰة ﻣﺜــﻞ اﻟﺤﻠﻘــﺎت أو اﻟﺤﻠﺰوﻧﺎت . ﺑﻤﻌﻨﻰ آﺧﺮ ﻳﻤﻜﻦ ﺗﻔﺴ ﻣﺨﺘﻠﻒ اﻟﺒﻨﻰ اﻟﻔﺮﻋﻴﺔ ﻟﻠﻘﺮص ﻋـﲆ اﻧﻬـﺎ رﺳـﺎﺋﻞ " " أﻧﻬﺎ رﺳﺎﺋﻞ " " ﻣﻦ اﻟﻜﻮاﻛﺐ ا ﺘﺸﻜﻠﺔ . ﻟﺪراﺳﺔ ﻣﻦ اﻟﻜﻮاﻛﺐ ا ﺘﺸﻜﻠﺔ ﻟﺪ. راﺳﺔ ﻫـﺬه اﻟﺒﻨـﻰ اﻟﻔﺮﻋﻴﺔ ﺑﺎﻟﺘﻔﺼﻴﻞ ﻳﻠﺰم إﺟﺮاء ﻋﻤﻠﻴﺎت رﺻﺪ رادﻳﻮﻳﺔ ﻋﺎﻟﻴﺔ اﻟﺪﻗﺔ ﺑﺎﺳﺘﺨﺪام ﺗﻠﺴﻜﻮب أ ـﺎ وﻗﺪ أُﺟﺮﻳﺖ ﺣﺘ ﻰ اﻵن اﻟﻌﺪﻳـﺪ ﻣـﻦ ﻋﻤﻠﻴـﺎت اﻟ ﺮﺻــﺪ ﻟﻸﻗــﺮاص اﻟﻜﻮﻛﺒﻴــﺔ اﻷوﻟ أو ) ﻴــﺔ اﻷﻗـﺮاص ا ﺤﻴﻄـﺔ ﺑـﺎﻟﻨﺠﻮم ( وﻋـﲆ وﺟـﻪ اﻟﺨﺼﻮص ﻛﺸﻒ ﺑﺮﻧﺎ ﻣﺠﺎن ﻛﺒ ان ﺗﺎﺑﻌـﺎن ﻟﺘﻠﺴــﻜﻮب أ ــﺎ ) ﻫﻤــﺎ دي ﺷــﺎرب إي )و ( دﻳﺴـﻚ ( ﻋـﻦ اﻟﺘﻮزﻳـﻊ اﻟﺘﻔﺼـﻴﲇ ﻟﻠﻐﺒـﺎر ﰲ اﻷﻗﺮاص اﻟﻜﻮﻛﺒﻴﺔ اﻷوﻟﻴﺔ ﻣﻦ ﺧﻼل ﻋﻤﻠﻴـﺎت رﺻ ﺪ ﻋﺎﻟﻴﺔ اﻟﺪﻗـﺔ . اﻛﺘﺸـﻒ ﻣـ دي )ﴩوع ـ ﺑﺄ( ﺷﺎرب ن اﻟﺒﻨﻰ ا ﻤﻴﺰة ﺷﺎﺋﻌﺔ ﰲ اﻷﻗﺮاص ا ﺤﻴﻄـﺔ ﺑـﺎﻟﻨﺠﻮم ﺣــﻮل 20 ﺎً ﻧﺠﻤـ ﺎً ﺷـﺎﺑ ﻳﺘﺠﺎوز ﻋﻤﺮ ﻛﻞ ﻣﻨﻬﺎ ﻣﻠﻴﻮن ﺳﻨﺔ ﻣﻨﺬ ﺑﺪ اﻳـﺔ ﺗﻜـﻮﻳﻦ اﻟﻨﺠـﻮم . ﻣــﻦ ﻧﺎﺣﻴـﺔ أﺧـﺮى ﻋﺜـﺮ ـﻣ )ﴩوع إي دﻳﺴـﻚ ( ﻋـﲆ ﻋـﺪد أﻗـﻞ ﻣـﻦ اﻟﻬﻴﺎﻛﻞ ا ﻤﻴﺰة ﺣﻴﺚ درس اﻷﻗﺮاصﺣﻮل 19 أوﻟﻴ ﺎً ﻧﺠﻤ ﺎً ﰲ ﻣﺮﺣﻠﺔ اﻟﱰاﻛﻢ ﻣﺮﺣﻠﺔ ) ﻳﻜـﻮن ﻓﻴﻬﺎ ﺗـﺮاﻛﻢ اﻟﻜﺘﻠـﺔ ﻋـﲆ اﻟـﻨﺠﻢ واﻟﻘـﺮص ﻧﺸﻄًﺎ .( ﺗﺤـﺪث ﻫـﺬه ا ﺮﺣﻠـﺔ ﺑﻌـﺪ ﺣـﻮاﱄ ﺗﺒﺪأ (. ﺎً ﻧﺸﻄ ﻫﺬه ا ﺮﺣﻠﺔ ﺑﻌﺪ ﺣﻮاﱄ 10,000 إﱃ 100,000 ﺳﻨﺔ ﻣـﻦ وﻻدة اﻟـﻨﺠﻢ وﻫـﺬا ﻳﺸ ـ إﱃ أن اﻷﻗ ـﺮاص ﺗﺘﻤﻴ ـﺰ ﺑﺨﺼ ـﺎﺋﺺ ﻣﺘﻨﻮﻋﺔ ﺗﻌﺘﻤﺪ ﻋﲆ ﻋﻤﺮ اﻟﻨﺠﻢ ا ﻀﻴﻒ . ﻟﻜﻦ اﻟﺴﺆال ا ﺤﻮري ﻫﻮ ﻣﺘﻰ ﺗﺒـﺪأ اﻟﻬﻴﺎﻛـﻞ اﻟﻔﺮﻋﻴ ﺔ اﻟﺘﻲ ﺗﻌﺪ ﻣﺆﴍات ﻣﺒﻜﺮة ﻋﲆ ﺗﺸﻜﻞ اﻟﻜﻮاﻛﺐ داﺧﻞ ﻫﺬه اﻷﻗﺮاص؟ ﻟﻠﻮﺻﻮل إﱃ إﺟﺎﺑﺔ ﻳﺠﺐ رﺻﺪ أﻗﺮاص ﻛﻮﻛﺒﻴﺔ ﻣ ﻦ ﻣﺠﻤﻮﻋﺔ واﺳـﻌﺔ ﻣـﻦ ﻣﺮاﺣـﻞ ﻋﻤﺮﻳـﺔ ﻣﺘﻮﺳﻄﺔ وﻫﻲ ﻓﺌﺔ ﻻ ﺗـﺰال ﻏـ ﻣﻜﺘﺸـﻔﺔ ﻏ أن ﻫﻨـﺎك ﺗﺤـﺪﻳﺎت ﻛﺒـ ة ﺗﻮاﺟـﻪ ﻫـﺬا ا ﺴﻌﻰ أﺑﺮزﻫﺎ اﻟﻘﻴﻮد ا ﺮﺗﺒﻄﺔ ﺑ ﻌﺪد اﻷﻗﺮاص اﻟﻘﺎﺑﻠﺔ ﻟﻠﺮﺻﺪ ﺑﺪﻗﺔ ﻋﺎﻟﻴﺔ وذﻟﻚ ﺑﺴﺒﺐ اﻟ ﺒﻌﺪ اﻟﻜﺒ ﻗﻴﻮد و وﻗـﺖ اﻟﺮﺻـﺪ ﻣـﺎ ﻳ ﺠﻌـﻞ ﻣـﻦ اﻟﺼﻌﺐ ﺗﻨﻔﻴـﺬ ﻣﺴـﺢ إﺣﺼـﺎﺋﻲ ذي دﻻﻟـﺔ ﻋﻠﻤﻴﺔ وﻋﻴﻨﺔ ﻛﺒ ة . ﻣﻦ ﺧﻼل ﺗﺤﻠﻴﻞ ﺑﻴﺎﻧﺎت اﻟﺘﻠﺴـﻜﻮﺑﺎت ﻳﻤﻜـﻦ ﺗﺘﺒـﻊ ﺗﻄـﻮ ر اﻟﻬﻴﺎﻛـﻞ اﻟﻔﺮﻋﻴــﺔ ﺑﺸـﻜﻞ أﻓﻀـﻞ وﺗﺤﺪﻳـﺪ اﻷوﻗـﺎت اﻟﺤﺮﺟﺔ اﻟﺘﻲ ﺗﺒﺪأ ﻓﻴﻬﺎ اﻟﻜﻮاﻛﺐ ﺑﺎﻟﺘﺸﻜﻞ . ﺗــﻮﻓﺮ وﺣــﺪة ﻣﺮﻛــﺰأﻟﻤــ ﺎ اﻹﻗﻠ ﻤــﻲ ﻟـﺪول اﻟﺸــﻤﺎل اﻷوروﺑـــــــــــــﻲ اﻟﻤﻮﺟـــــــــــــﻮدة ﻓـــــــــــــﻲﻣﺮﺻـــــــــــــﺪ أوﻧﺴـــــــــــــﺎﻻ اﻟﻔﻀﺎﺋﻲ دﻋﻤًﺎ ﺎﻣﻼً ﻟﻤﺴﺘﺨﺪﻣﻲ ﻣﺮﺻﺪ أﻟﻤﺎ ﻓـﻲ دول اﻟﺸــــــــــــــﻤﺎل اﻷوروﺑـــــــــــــــﻲ اﻟـــــــــــــــﺪﻧﻤﺎرك و ﻓﻨﻠﻨـــــــــــــــﺪا و أ ﺴـــــــــــﻠﻨﺪا اﻟـــــــــــ وﻳـﺞ و و اﻟﺴـــــــــــﻮ ﺪ ودول اﻟ ﻠﻄﻴـــــــــــﻖ ﻟ ﺘﻮاﻧ ﺎ ﻻﺗﻔ ﺎ إﺳﺘﻮﻧ ﺎ و . [ESO/S.Guisard]