Free Astronomy Magazine September-October 2025 ARABIC VERSION

34 The dawn of a new solar system byESO BárbaraFerreira or the first time, we have identifiedtheearliestmo- mentwhenplanetforma- tionisinitiatedaroundastarother than our Sun,” says Melissa McClure, a professor at Leiden University in theNetherlandsandleadauthorof thenewstudy,publishedin Nature . Co-authorMerelvan‘tHoff,apro- fessor at Purdue University, USA, comparestheirfindingsto “apicture of the baby Solar System” , saying that “we’re seeing a system that looks like what our Solar System lookedlikewhenitwasjustbegin- ning to form.” This newborn planetary system is emerging around HOPS-315, a‘proto’ or baby star that sits some 1300 light-years away from us and is an analogue of the nascent Sun. Around such baby stars, astronomers often see discs of gas and dustknown as ‘protoplanetary discs’, which are the birthplaces of new planets. While astronomers have previouslyseenyoungdiscsthat con- tain newborn, massive, Jupiter-like planets,McCluresays, “we’vealways known that the first solid parts of planets, or ‘planetesimals’, must formfurtherbackintime,atearlier stages.” In our Solar System, the very first solid material to condense near Earth’spresentlocationaroundthe Sunisfoundtrappedwithinancient meteorites. Astronomers age-date theseprimordialrockstodetermine whentheclockstartedonourSolar System’s formation. Such meteorites arepackedfullofcrystallineminer- als that contain silicon monoxide (SiO) and can condense at the ex- tremely high temperatures present inyoungplanetarydiscs.Overtime, these newly condensed solids bind together, sowing the seeds for planet formation as they gain both size and mass. The first kilometre- sizedplanetesimalsintheSolarSys- tem,whichgrewtobecomeplanets such as Earth or Jupiter’s core, formedjustafterthecondensation SEPTEMBER-OCTOBER2025 ﺗﻮﺛﻴﻖ ﻓﺠﺮﻧﻈﺎم ﺷﻤﺴﻲﺟﺪ ﺪ ﻗﺎﻟـﺖ ﻣﻴﻠﻴﺴﺎ ﻣﺎﻛﻠﻮر اﻷﺳـﺘﺎذة ﰲ ﺟﺎﻣﻌـﺔ ﻻﻳﺪن ﺑﻬﻮﻟﻨﺪا وا ﺆﻟﻔـﺔ اﻟﺮﺋﻴﺴـﻴﺔ ﻟﻠﺪراﺳـﺔ ا ﻟﺠﺪﻳﺪة ا ﻨﺸﻮرة ﰲ ﻣﺠﻠﺔ ﻧﻴﺘﴩ :" إﻧﻬﺎ ا ﺮة اﻷوﱃ اﻟﺘﻲ ﻧﺤﺪد ﻓﻴﻬﺎ أﻗـﺪم ﻟﺤﻈـﺔ ﻟﺘﺸـﻜﻞ اﻟﻜﻮاﻛﺐ ﺣﻮل ﻧﺠﻢ ﻏ اﻟ ". ﺸﻤﺲ ﺗﻘﺎ و رن ﻣ ﻳﻠﻔﺎن ﻫﻮف ا ﺆﻟﻔﺔ ا ﺸـﺎرﻛﺔ ﰲ اﻟﺪراﺳﺔ واﻷﺳﺘﺎذة ﰲ ﺟﺎﻣﻌﺔ ﺑ دو ﺑﺎﻟﻮﻻﻳﺎت ا ﺘﺤﺪة اﻷﻣﺮﻳﻜﻴﺔ ﻧﺘﺎﺋﺠﻬﻢ ﺑـ " ﺻﻮرة ﻟﻠﻨﻈﺎم اﻟﺸﻤﴘ ﰲ ﺑﺪاﻳﺎﺗ ﻪ : " ﻗﺎﺋﻠﺔً إﻧﻨﺎ ﻧـﺮى ﻧﻈﺎﻣـ ﺎً ﻳﺸﺒﻪ ﻣﺎ ﻛﺎن ﻋﻠﻴﻪ ﻧﻈﺎﻣﻨﺎ اﻟﺸ ـ ﻤﴘ ﻋﻨـﺪﻣﺎ ﻛﺎن ﰲ ﺑﺪاﻳﺔ ﺗﺸﻜﻠﻪ ." ﻳﻨﺸﺄ ﻫﺬا اﻟﻨﻈﺎم اﻟﻜـﻮﻛﺒﻲ ﺣـﺪﻳﺚ ا ﻟـﻮﻻدة ﺣﻮل اﻟﻨﺠﻢ HOPS-315 وﻫﻮ ﻧﺠﻢ ﺑـﺪاﺋﻲ أو ﻧﺠﻢ وﻟﻴﺪ ﻳﺒﻌﺪ ﻋﻨﺎ ﺣﻮاﱄ 1300 ﺳﻨﺔ ﺿﻮﺋﻴﺔ وﻫﻮ ﺷﺒﻴﻪ ﺑﺎﻟﺸﻤﺲ ﺣﺪﻳﺜﺔ اﻟﺘﻜﻮﻳﻦ . ﺣﻮل ﻫﺬه اﻟﻨﺠﻮم اﻟﻮﻟﻴـﺪة ﻏﺎﻟﺒـﺎً ﻣـﺎ ﻳﺮﺻـﺪ ﻋﻠﻤﺎء اﻟﻔﻠﻚ أﻗﺮاﺻ ﺎً ﻣﻦ اﻟﻐﺎز واﻟﻐﺒﺎر ﺗُﻌﺮف ﺎﺳﻢ ﺑ " اﻷﻗﺮاص اﻟﻜﻮﻛﺒﻴـﺔ اﻟﺒﺪاﺋﻴـﺔ " وﻫـﻲ ﻣﻬﺪ اﻟﻜﻮاﻛﺐ اﻟﺠﺪﻳﺪة ﻤﺎ وﺑﻴﻨ . ﺳﺒﻖ ﻟﻌﻠﻤـﺎء اﻟﻔﻠﻚ أن رﺻﺪوا أﻗﺮاﺻ ﺎً وﻟﻴﺪة ﺗﺤﺘـﻮ ي ﻋـﲆ ﻛﻮاﻛﺐ ﺣﺪﻳﺜﺔ اﻟﻮﻻدة، ﺿﺨﻤﺔ ﺗﺸﺒﻪ ﻛﻮﻛـﺐ ا ﺸﱰي . ﻳﻘﻮل ﻣـﺎﻛﻠﻮر " : ﻟﻄﺎ ـﺎ ﻋﺮﻓﻨـﺎ أن اﻷ ﺟــﺰاء اﻟﺼــﻠﺒﺔ اﻷوﱃ ﻣــﻦ اﻟﻜﻮاﻛــﺐ أو " اﻟﻜﻮاﻛـﺐ ا ﺼـﻐﺮة " ﻳﺠـﺐ أن ﺗﺘﺸـﻜﻞ ﰲ ﻣﺮاﺣﻞ ﺳﺎﺑﻘﺔ ﻣﻦ اﻟﺰﻣﻦ ." ﻟﻘﺪ و ﺟﺪت أول ﻣﺎدة ﺻﻠﺒﺔ ﺗﻜﺜﻔﺖ ﰲ ﻧﻈﺎﻣﻨﺎ اﻟﺸﻤﴘ ﺑﺎﻟﻘﺮب ﻣـﻦ ﻣﻮﻗـﻊ اﻷرض اﻟﺤـﺎﱄ ﺣـﻮل اﻟﺸـﻤﺲ ﻣﺤﺼـﻮرة داﺧـﻞ اﻟﻨﻴـﺎزك اﻟﻘﺪﻳﻤﺔ . ﻫﺬه اﻻﻛﺘﺸﺎﻓﺎت ﺗﻘﺪم أدﻟﺔ ﺣﺎﺳﻤﺔ ﺣﻮل ﻇـﺮوف ﻧ ﺸـﺄة ﻣﺠﻤﻮﻋﺘﻨـﺎ اﻟﺸﻤﺴـﻴﺔ وﺗﺆﻛﺪ أن اﻟﻌﻨﺎﴏ اﻷﺳﺎﺳﻴﺔ ﻟﺒﻨﺎء اﻟﻜﻮاﻛـﺐ ﻛﺎﻧﺖ ﻣﻮﺟﻮدة ﻣﻨﺬ اﻟﺒﺪاﻳﺔ . ﻳ ﺤـﺪد ﻋﻠﻤـﺎء اﻟﻔﻠـﻚ ﻋﻤـﺮ ﻫـﺬه اﻟﺼـﺨﻮر اﻟﺒﺪاﺋﻴﺔ ﻟﺘﺤﺪﻳﺪ ﻣﺘﻰ ﺑﺪأت اﻟﺴﺎﻋﺔ ﰲ ﺗﻜـﻮﻳﻦ ﻧﻈﺎﻣﻨ ـﺎ اﻟﺸـــﻤﴘ . ﻫ ـﺬه اﻟﻨﻴ ـﺎزك ﻣﻠﻴﺌ ـﺔ ﺑﺎ ﻌﺎدن اﻟﺒﻠﻮرﻳﺔ اﻟﺘﻲ ﺗﺤﺘﻮي ﻋﲆ أول أﻛﺴﻴﺪ اﻟﺴﻴﻠﻴﻜﻮن وﻳﻤﻜﻦ أن ﺗﺘﻜﺜﻒ ﻋﻨـﺪ درﺟـﺎت اﻟﺤﺮارة اﻟﻌﺎﻟﻴﺔ اً ﺟـﺪ ا ﻮﺟـﻮدة ﰲ اﻷﻗـﺮاص اﻟﻜﻮﻛﺒﻴﺔ اﻟﺤﺪﻳﺜﺔ . ﺑﻤﺮور اﻟﻮﻗـﺖ ﺗـﱰاﺑﻂ ﻫـ ﺬه ا ـﻮاد اﻟﺼـﻠﺒﺔ ا ﻜﺜﻔﺔ ﺣﺪﻳﺜﺎً ﻣﻤﺎ ﻳﻤﻬـﺪ اﻟﻄﺮﻳـﻖ ﻟﺘﻜـﻮﻳﻦ اﻟﻜﻮاﻛـﺐ ﻣـﻊ اﻛﺘﺴـﺎﺑﻬﺎ اﻟﺤﺠـﻢ واﻟﻜﺘﻠـﺔ . ﺗﺸﻜﻞ أول ﻛﻮاﻛﺐ ﻣﺼﻐﺮة ﺑﺤﺠﻢ ﻛﻴﻠﻮﻣﱰ ﰲ اﻟﻨﻈﺎم اﻟﺸ ﻤﴘـ واﻟﺘﻲ ﻧﻤﺖ ﻟﺘﺼﺒﺢ ﻛﺐ ﻛﻮا ﻣﺜﻞ اﻷرض أو ﻧـﻮاة ا ﺸـﱰي ﻣﺒـﺎﴍة ﺑﻌـﺪ ﺗﻜﺜﻒ ﻫﺬه ا ﻌﺎدن اﻟﺒﻠﻮرﻳﺔ . ﻣﺠﻠﺔ FreeAstronomy ﺎﻟﻌﺮ ﺔ : ﻠﻢ ﻘ ﺎر ﺮا ﻓ ﺮا اﻟﻤﺮﺻﺪ اﻷورو ﺑﻲ اﻟـﺠﻨﻮﺑﻲ 34 ﺳﺒﺘﻤﺒﺮ - ﺃﻛﺘﻮﺑﺮ 2 0 2 5