Free Astronomy Magazine May-June 2026 ARABIC VERSION

MAY-JUNE2026 ASTROPUBLISHING 37 stronomershavediscovered one of the most chemically Vprimitivestarseveridentified — an ancient stellar relic that pre- serves the chemical imprint of the veryfirststarsintheUniverse.Thisstar ,namedPicII-503,residesinthe tiny,ultra-faintdwarfgalaxyPictor II.Thediscoverywasenabledbythe U.S. Department of Energy-fabri- cated Dark Energy Camera (DECam), mounted on the U.S. National Sci- enceFoundationVíctorM.Blanco4- meterTelescope,atNSFCerroTololo Inter-American Observatory (CTIO) inChile,aProgramofNSFNOIRLab. PictorIIislocatedintheconstella- tionPictor.Itcontainsseveralthou- sand stars and is more than ten billionyearsold.PicII-503liesonthe outskirts of the galaxy, and it con- tains less iron than any other star evermeasuredoutsideoftheMilky Way, while also having an extreme overabundanceofcarbon.Thesesig- natures unmistakably match those of carbon-enhanced stars found in theouterreachesoftheMilkyWay, whoseoriginshave,untilnow,been a mystery. ThestudywasledbyAnirudhChiti, BrinsonPrizeFellowatStanfordUni- versity,andtheresultsarepresented in a paper appearing in Nature As- tronomy . ThefirststarsintheUniverseformed from gas that contained only the simple elements, hydrogen and he- lium. Within their fiery cores, this first generation of stars created the first elements heavier than helium, such as carbon and iron, which as- tronomers refer to as “metals.” When these stars exploded, they re- leasedtheirheavyelementsintothe interstellar medium to be recycled into the next generation of stars. Second-generation stars are like time capsules, preserving the low amountsofheavyelementsreleased duringtheexplosivedeathsoffirst- generation stars. By searching for these rare, low-metallicity stars and deriving their chemistry, scientists can better understand the mecha- nismsofinitialelementproduction in the Universe. PicII-503isthefirstunambiguousex- ampleofasecond-generationstarin an ultra-faint dwarf galaxy. It was uncoveredindatafromtheDECam MAGIC (Mapping the Ancient Gal- axyinCaHK)survey,a54-nightob- serving program designed to iden- tifytheoldestandmostchemically primitivestarsintheMilkyWayand itsdwarfgalaxycompanions.Using aspecializednarrow-bandfiltersen- sitivetocalciumabsorptionfeatures, astronomerswereabletoestimate the metal content of thousands of stars from imaging data alone. Among the hundreds of stars near PictorII,MAGICdatasingledoutPic- II- 503asanexceptionallymetal-poor ﻣﺠﻠﺔ FreeAstronomy ﺎﻟﻌﺮ ﺔ 37 اﻛﺘﺸـﻒ ﻋﻠﻤ ﺎء اﻟﻔﻠﻚ أﺣﺪ أﻛﺜﺮ اﻟﻨﺠﻮم ﺑﺪاﺋﻴﺔ ﻣﻦ ﺣﻴﺚ اﻟﱰﻛﻴﺐ اﻟﻜﻴﻤﻴـﺎﺋﻲ ﺗـﻢ ﺗﺤﺪﻳـﺪﻫﺎ ﺣﺘﻰ اﻵن وﻫﻮ ﺑﻘﺎﻳﺎ ﻧﺠﻤﻴﺔ ﻗﺪﻳﻤﺔ ﺗﺤـﺘﻔﻆ ﺑﺎﻟﺒﺼﻤﺔ اﻟﻜﻴﻤﻴﺎﺋﻴﺔ ﻟﻠﻨﺠﻮم اﻷوﱃ ﰲ اﻟﻜـﻮن . ﻳﺤﻤﻞ ﻫـﺬا اﻟـﻨﺠﻢ اﺳـﻢ PicII-503 ﻊ وﻳﻘـ داﺧﻞ ا ﺠ ﺮة اﻟﻘﺰﻣﺔ اﻟﺨﺎﻓﺘﺔ ﺟـﺪ ا Pictor II . وﻗﺪ أُﺗـﻴﺢ ﻫـﺬا اﻻﻛﺘﺸـﺎف ﺑﻔﻀـﻞ ﻛـﺎﻣ ا اﻟﻄﺎﻗﺔ ا ﻈﻠﻤﺔ ) دي ﻛﺎم اﻟﺘﻲ ( ﻌﺻـﻨ ﺖ ﻣـﻦ ﻗﺒﻞ وزارة اﻟﻄﺎﻗﺔ اﻷﻣﺮﻳﻜﻴـﺔ وا ﺜﺒﺘـﺔ ﻋـﲆ ﺗﻠﺴﻜﻮب ﻓﻴﻜ ﺘﻮر ﺑﻼﻧﻜﻮ ﺑﻘﻄﺮ 4 أﻣﺘﺎر اﻟﺘﺎﺑﻊ ﺆﺳﺴﺔ اﻟﻌﻠﻮم اﻟﻮﻃﻨﻴﺔ اﻷﻣﺮﻳﻜﻴﺔ ﰲ ﻣﺮﺻﺪ ﺳ و ﺗﻮﻟﻮﻟـﻮ ﰲ ﺗﺸـﻴﲇ وﻫـﻮ أﺣـﺪ ﺑـ ﺮاﻣﺞ ﻣﺨﺘﱪ ﻧﻮﻳﺮﻻب . ﺗﻘـﻊ ﻣﺠـﺮة ﺑﻴﻜﺘـﻮر II ﰲ ﻛﻮﻛﺒﺔ ﺑﻴﻜﺘﻮر اﻟﺮﺳﺎم ) ( وﺗﻀﻢ ﻋﺪة آﻻف ﻣﻦ اﻟﻨﺠﻮم وﻳﺰﻳﺪ ﻋﻤﺮﻫﺎ ﻋـﻦ ﻋﴩـة ﻣﻠﻴـﺎرات . ﺳﻨﺔ ﻳﻘﻊ اﻟﻨﺠﻢ PicII-503 ﰲ أﻃﺮاف ﻫـﺬه ا ﺠﺮة وﻳﺤﺘﻮي ﻋﲆ ﻛﻤﻴﺔ ﻣﻦ اﻟﺤﺪﻳﺪ أﻗﻞ ﻣﻦ أي ﻧﺠﻢ آﺧﺮ ﺗﻢ ﻗﻴﺎﺳـﻪ ﺧـﺎرج ﻣﺠـﺮة درب اﻟﺘﺒﺎﻧﺔ، ﻛﻤﺎ ﻳُﻈﻬﺮ وﻓﺮة ﻣﻔﺮﻃ ﺔ ﻣﻦ اﻟﻜﺮﺑﻮن وﺗﺘﻄﺎﺑﻖ ﻫﺬه اﻟﺴﻤﺎت ﺑﺸـﻜﻞ واﺿـﺢ ﻣـﻊ ﺧﺼﺎﺋﺺ اﻟﻨﺠﻮم ا ﻌﺰزة ﺑﺎﻟﻜﺮﺑﻮن اﻟﺘﻲ ﺗـﻢ رﺻﺪﻫﺎ ﰲ اﻷﻃـﺮاف اﻟﺨﺎرﺟﻴـﺔ ﺠـﺮة درب رﺻﺪﻫﺎ ﰲ اﻷ ﻃـﺮاف اﻟﺨﺎرﺟﻴـﺔ ﺠـﺮة درب اﻟﺘﺒﺎﻧﺔ واﻟﺘﻲ ﻇﻞ أﺻﻠﻬﺎ ﻏ ﻣﻔﻬـﻮم ﺣﺘـﻰ اﻵن . ﻗﺎد ﻫﺬه اﻟﺪراﺳﺔ أﻧ ود ﺗﺸـﻴﺘﻲ زﻣﻴـﻞ ﺟﺎﺋﺰة ﺑﺮﻳﻨﺴﻮن ﰲ ﺟﺎﻣﻌﺔ ﺳـﺘﺎﻧﻔﻮرد وﻗـﺪ ﻧُﴩت اﻟﻨﺘﺎﺋﺞ ﰲ ورﻗﺔ ﻋﻠﻤﻴﺔ ﰲ ﻣﺠﻠﺔ ﻧﻴﺘﴩ اﺳﱰوﻧﻮﻣﻲ . ﺗﻜﻮّﻧﺖ اﻟﻨﺠﻮم اﻷوﱃ ﰲ اﻟﻜـﻮن ﻣﻦ ﻏﺎز ﻳﺤﺘﻮي ﻓﻘﻂ ﻋﲆ اﻟﻌﻨﺎﴏ اﻟﺒﺴﻴﻄﺔ : اﻟﻬﻴﺪروﺟ واﻟﻬﻴﻠﻴﻮم وداﺧﻞ أﻧﻮﻳﺘﻬﺎ ا ﻠ ﺘﻬﺒﺔ أﻧﺘﺠﺖ ﻫﺬه اﻟﻨﺠﻮم اﻟﺠﻴﻞ اﻷول أوﱃ اﻟﻌﻨﺎﴏ اﻷﺛﻘﻞ ﻣ اﻟﻬﻠﻴﻮم ﻦ ﻣﺜـﻞ اﻟﻜﺮﺑـﻮن واﻟﺤﺪﻳـﺪ واﻟ ﺘـﻲ ﻳﻄﻠــﻖ ﻋﻠﻴﻬ ـﺎ ﻋﻠﻤـﺎء اﻟﻔﻠ ـﻚ اﺳـﻢ اﻟﻔﻠﺰات " " وﻋﻨـﺪﻣﺎ اﻧﻔ ﺠـﺮت ﻫـﺬه اﻟﻨﺠـﻮم أﻃﻠﻘﺖ ﻋﻨﺎﴏ ﻫـﺎ اﻟﺜﻘﻴﻠـﺔ إﱃ اﻟﻮﺳـﻂ ﺑـ اﻟﻨﺠﻤﻲ ﻟﻴ ﻌﺎد ﺗﺪوﻳﺮﻫﺎ ﰲ ﺗﻜﻮﻳﻦ اﻟﺠﻴﻞ اﻟﺘﺎﱄ ﻣﻦ اﻟﻨﺠﻮم ﺗ. ﻌﺪ ﻧﺠﻮم اﻟ ﺠﻴ ﻞ اﻟﺜﺎﻧﻲ ﺑﻤﺜﺎﺑـﺔ ﻛﺒﺴــﻮﻻت زﻣﻨﻴــﺔ إذ ﺗﺤــﺘﻔﻆ ﺑﺎﻟﻜﻤﻴــﺎت اﻟﻀﺌﻴﻠﺔ ﻣﻦ اﻟﻌﻨﺎﴏ اﻟﺜﻘﻴﻠﺔ اﻟﺘـﻲ أُﻃﻠﻘـﺖ ﺧﻼل اﻻﻧﻔﺠﺎرات اﻟﻨﺠﻤﻴﺔ ﻟﻠﺠﻴﻞ اﻷول وﻣـﻦ ﺧــﻼل اﻟﺒﺤـﺚ ﻋـﻦ ﻫـﺬه اﻟﻨﺠـﻮم اﻟﻨـﺎدرة ﻣﻨﺨﻔﻀﺔ اﻟ ﻔﻠﺰّﻳﺔ وﺗﺤﻠﻴﻞ ﺗﺮﻛﻴﺒﻬﺎ اﻟﻜﻴﻤﻴﺎﺋﻲ ﻳﻤﻜﻦ ﻟﻠﻌﻠﻤﺎء ﻓﻬـﻢ آﻟﻴـﺎت إﻧﺘـﺎج اﻟﻌﻨـﺎﴏ اﻷوﱃ ﰲ اﻟﻜﻮن ﺑﺸـ ﻜﻞ أﻓﻀـﻞ . ﻳُﻌـﺪ اﻟـﻨﺠﻢ اﻷوﱃ ﰲ اﻟﻜﻮن ﺑﺸـﻜﻞ أﻓﻀـﻞ ﻳ. ﻌـﺪ اﻟـﻨﺠﻢ PicII-503 أول ﻣﺜـﺎل واﺿـﺢ ﻻ ﻟـﺒﺲ ﻓﻴـﻪ ﻟﻨﺠﻢ ﻣﻦ اﻟﺠﻴﻞ اﻟﺜ ﺎﻧﻲ ﰲ ﻣﺠﺮة ﻗﺰﻣﺔ ﻓﺎﺋﻘﺔ اﻟﺨﻔﻮت . وﻗﺪ ﺗـﻢ اﻛﺘﺸـﺎﻓﻪ ﺿـﻤﻦ ﺑﻴﺎﻧـﺎت " ﻣﺴﺢ دي ﻛﺎم ﻣﺎﺟﻴﻚ " وﻫﻮ ﺑﺮﻧﺎﻣﺞ رﺻﺪي اﺳـﺘﻤﺮ 54 ﻟﻴﻠـﺔ وﻳﻬـﺪف إﱃ ﺗﺤﺪﻳــﺪ أﻗـﺪم اﻟﻨﺠﻮم وأﻛﺜﺮﻫﺎ ﺑﺪاﺋﻴـﺔً ﻛﻴﻤﻴﺎﺋﻴـ ﺎً ﰲ ﻣﺠـﺮة درب اﻟﺘﺒﺎﻧ ـﺔ وﻣﺠﺮاﺗﻬ ـﺎ اﻟﻘﺰﻣ ـﺔ اﻟﺘﺎﺑﻌ ـﺔ . وﺑﺎﺳﺘﺨﺪام ﻣﺮﺷﺢ ﺿﻴﻖ اﻟﻨﻄـ ﺎق ﺣﺴـﺎس ﻴﺰات اﻣﺘﺼﺎص اﻟﻜﺎﻟﺴـ ﻴﻮم ﺗﻤﻜـﻦ ﻋﻠﻤـﺎء اﻟﻔﻠـﻚ ﻣـﻦ ﺗﻘـﺪﻳﺮ ﻣﺤ ﺘـﻮى اﻟﻔﻠـﺰات ﻵﻻف اﻟﻨﺠﻮم اﻋﺘﻤﺎد اً ﻋﲆ ﺑﻴﺎﻧﺎت اﻟﺘﺼـﻮﻳﺮ ﻓﻘـﻂ . وﻣﻦ ﺑ ﻣﺌﺎت اﻟﻨﺠﻮم اﻟﻘﺮﻳﺒـﺔ ﻣـﻦ ﻣﺠـﺮة ﺑﻴﻜﺘﻮر II اﻇﻬـﺮت ﺑﻴﺎﻧـﺎت ﻣﺴـﺢ ﻣﺎﺟﻴـﻚ اﻟــﻨﺠﻢ PicII-503 ﻛﻤﺮﺷــﺢ اﺳــﺘﺜﻨﺎﺋﻲ ﻣﻨﺨﻔﺾ اﻟﻔﻠﺰﻳﺔ ﻣﻤﺎ أﺗﺎح ﺗﻮﺟﻴﻪ دراﺳـﺎت ﻣﺘﺎﺑﻌـﺔ ﻧﺤــﻮه . ﻳﻘـﻮل ﺗﺸــﻴﺘﻲ ون ﻣـﻦ د »: ﺑﻴﺎﻧﺎت " ﻣﺴﺢ ﻣﺎﺟﻴﻚ " ﻛﺎن ﻣـﻦ ا ﺴـﺘﺤﻴﻞ ﻋﺰل ﻫﺬا اﻟﻨﺠﻢ ﻣﻦ ﺑ ﻣﺌﺎت اﻟﻨﺠﻮم اﻷﺧﺮى ﰲ ﻣﺤﻴﻂ ا ﺠـﺮة اﻟﻘﺰﻣـﺔ ﻓﺎﺋﻘـﺔ اﻟﺨﻔـﻮت ﺑﻴﻜﺘﻮر II« . وﻣﻦ ﺧﻼل دﻣﺞ ﺑﻴﺎﻧـﺎت ا ﺴـﺢ ﻣ ـﻊ أرﺻـﺎد ﺗﻠﺴـﻜﻮب Magellan/Baade ﺗﻈﻬﺮ ﻫﺬﻩ اﻟﺼﻮرة ﻧﺠﻮﻣﺎً ﻓﻲ اﻟﻤﺠﺮ ة اﻟﻘﺰﻣﺔ اﻟ ـ ﺨﺎﻓﺘﺔ ﻟﻠﻐﺎ ﺔ ﺑ ﻜﺘﻮر II . وﻫﻲﻣﺠﺮة ﺪورﻫﺎ ﻣﺠﺮة ﺗﺎ ﻌﺔ ﻟﺴﺤﺎ ﺔ ﻣﺎﺟﻼن اﻟﻜ ىواﻟ ﺗﺎ ﻌﺔ ﻟﻤﺠﺮة در ـــﺔ ﺑ ﻜﺘــﻮر اﻟﺘ ﺎﻧــﺔ وﺗﻘـــﻊ ﻓــﻲ ﻮﻛ . ـــﺎراتﺳــﻨﺔ ـــﻮن ﻫــﺬا اﻟﻨﻈـــﺎم ﻣــﻦ ﻋـــﺪة آﻻفﻣــﻦ اﻟﻨﺠـــﻮم وﻳ ﻠــﻎ ﻋﻤـــﺮﻩ أﻛــ ﻣـــﻦ ﻋﺸــﺮة ﻣﻠ ﺘ . ﺿـــﻤﻦ ﻫــﺬﻩ اﻟﻤﺠـــﺮة اﻟﺼـــﻐ ة اﻟﻘﺪ ﻤﺔ اﻛﺘﺸﻒﻋﻠﻤ ﺎء اﻟﻔﻠﻚ ﻧ ﻤﺎً، PicII-503 ، ﻳﺤﺘﻮيﻋﻠﻰ أﻗﻞ ﻧﺴ ﺔ ﻣﻦ اﻟ ـ ﺤﺪ ﺪ ﺗﻢﻗ ﺎﺳـﻬﺎ ﻋﻠـﻰ اﻹﻃـﻼقﺧـﺎرج ﻣﺠـﺮة در اﻟﺘ ﺎﻧـﺔ . إذ ﻳﺤﺘـﻮيﻋﻠـﻰ أﻗـﻞ ﻣــﻦ 1/ 40.000 ــﺔ اﻟـــﺤﺪ ﺪ اﻟﻤﻮﺟــﻮدة ﻓــﻲ اﻟﺸــﻤﺲو ﻌــﺪ اﻟــﻨ ﻢ ﻣــﻦ ﻤ PicII-503 ـــﺎﺋﻲ ــﺐ اﻟﻜ ﻤ ــﺪاﺋﻲ ﻳﺤــﺘﻔﻆ ﺎﻟ ﻛ ــﻢﺿــﻤﻦ ﻧﻈــﺎم أوﺿــﺢ ﻣﺜــﺎل ﻋﻠــﻰ ﻧ ـﻮن ﻟﻨﺠﻮم اﻟ اﻷوﻟـﻰ . ﻤـﺎ ﺘﻤـ PicII-503 ﺑـﻮﻓﺮة ﻫﺎﺋﻠـﺔ ﻣـﻦ اﻟﻜﺮـﻮن ﻣﻤـﺎ ﻳـﻮﻓﺮاﻟـ ـ رﺻـﺪت ﻓـﻲ ـﺎﻟﻜﺮﻮن اﻟـ ـﺔ اﻟﻨﺠـﻮم اﻟﻐﻨ ﺗـﺮﻂ ﺑـ ﺤﻠﻘﺔ اﻟﻤﻔﻘـﻮدة اﻟـ ﻫﺎﻟﺔ ﻣﺠﺮة در اﻟﺘ ﺎﻧﺔ وأﺻﻠﻬﺎ ﻓﻲ اﻟﻤﺠﺮات اﻟﻘﺰﻣﺔ اﻟﻘﺪ ﻤﺔ . [CTIO/NOIRLab/DOE/NSF/AURA. Imageprocessing: Image Processing: T.A. Rector (University of Alaska Anchorage/NSF NOIRLab), M. Zamani & D. de Martin (NSFOIRLab). Acknowledgment: PI: Anirudh Chiti, Alex Drlica-Wagner] - ﻣﺎﻳﻮ ﻳﻮﻧﻴﻮ 2 0 2 6