Free Astronomy Magazine May-June 2026 ARABIC VERSION

I T ofastar.AteamofastronomersusedtheGeminiHigh-resolutionOpticalSpectrograph(GHOST)ontheGeminiSouthtel- hisartist’sillustrationshowsalargediskofplanetarydebris,surroundedbyathickcloudofdustandgas,passinginfront escope,onehalfoftheInternationalGeminiObservatory,partlyfundedbytheU.S.NationalScienceFoundationandoperated byNSFNOIRLab,tomeasurethemotionofthegaswithinthecloud.Thisisthefirsttimeastronomershavemeasuredthein- ternalgasmotionsofadiskorbitingasecondaryobjectsuchasaplanetorlow-massstar.Thefindingoffersarareglimpse intothechaoticanddynamicprocessesstillshapingplanetarysystemslongaftertheirformation.[InternationalGeminiOb- servatory/NOIRLab/NSF/AURA/P. Marenfeld & M. Zamani] nSeptember2024,astar3000 light- years away suddenly became40 times dimmer than usual, and remainedsountilMay2025.Thestar, J0705+0612, is similar to our Sun, so its stark dip in brightness caught the attentionofNadiaZakamska,profes- sor of astrophysics at Johns Hopkins University. “Stars like the Sun don’t just stop shining for no reason,” she says, “sodramaticdimmingevents likethisareveryrare.” Recognizing the opportunity to study such an eventovermanymonths,Zakamska andherteaminitiatedobservations withtheGeminiSouthtelescope,lo- cated on Cerro Pachón in Chile, as well as the Apache Point Observa- tory3.5-metertelescopeandthe 6.5 meter Magellan Telescopes. The findings are published in a paper ap- pearingin The AstronomicalJournal . Bycombiningtheirobservationswith archival data on J0705+0612, the teamdeterminedthestarhadbeen occulted, or temporarily obscured by,avast,slow-moving,cloudofgas anddust.Theyestimatethecloudis abouttwobillionkilometers(1.2bil- lion miles) from its host star and roughly200millionkilometers(120 millionmiles)indiameter.Thedata indicatethatthiscloudisgravita- MAY-JUNE2026 ﻣﺠﻠﺔ FreeAstronomy ﺎﻟﻌﺮ ﺔ 17 ﺷـﻬﺪ ﻧﺠـﻢ ﰲ ﺳـﺒﺘﻤﱪ 2024 ﻳﺒﻌـﺪ ﺣـﻮاﱄ 3000 ﺳـﻨﺔ ﺿــﻮﺋﻴﺔ اﻧﺨﻔﺎﺿـ ﺎً ﰲ ﺎً ﻣﻔﺎﺟﺌـ ﺳﻄﻮﻋﻪ ﺑﻤﻘﺪار 40 ﻣﺮة ﻋﻦ ا ﻌﺘﺎد واﺳﺘﻤﺮ ﻫﺬا اﻻﻧﺨﻔـﺎض ﺣﺘـﻰ ﻣـﺎﻳﻮ 2025 . اﻟـﻨﺠﻢ J0705+0612 ﻣﺸﺎﺑﻪ ﻟﻠﺸـﻤﺲ ﻣﻤـﺎ ﺟﻌـﻞ ﻫﺬا اﻻﻧﺨﻔﺎض اﻟﺤﺎد ﰲ اﻟﺴﻄﻮع ﻳﻠﻔﺖ اﻧﺘﺒﺎه ﻧﺎدﻳﺎ زاﻛﺎﻣﺴﻜﺎ أﺳﺘﺎذة اﻟﻔﻴﺰﻳﺎء اﻟﻔﻠﻜﻴـﺔ ﰲ ﺟﺎﻣﻌـﺔ ﺟـﻮن ﻫـﻮﺑﻜﻨﺰ . ﺗﻘــﻮل : » اﻟﻨﺠـﻮم اﻟﺸﺒﻴﻬﺔ ﺑﺎﻟﺸ ﻤﺲ ﻻ ﺗﺘﻮﻗـﻒ ﻋـﻦ اﻹﺷـﻌﺎع ﺑﺪون ﺳﺒﺐ ﻟﺬا ﻓﺈن ﻣﺜﻞ ﻫـﺬه اﻻﻧﺨﻔﺎﺿـﺎت ـــــــــــــــــــــــــــــــــــــ اﻟﺪراﻣﺎﺗﻴﻜﻴﺔ ﻧﺎدرة ﺟﺪ . «اً اﺳﺘﻐﻠّﺖ زﻛﺎﻣﺴﻜﺎ وﻓﺮﻳﻘﻬﺎ اﻟﻔﺮﺻﺔ ﻟﺪراﺳﺔ ﻫﺬا اﻟﺤـﺪث ﻋـﲆ ﻣﺪار ﻋﺪة أﺷﻬﺮ، وأﺟﺮوا اﻟﺮﺻـﺪ ﺑﺎﺳـﺘﺨﺪام ﺗﻠﺴﻜﻮب ﺟﻴﻤﻴﻨﻲ اﻟﺠﻨﻮﺑﻲ ﰲ ﺳ و ﺑﺎﺷـﻮن ﺑﺘﺸـﻴﲇ، إﺿــﺎﻓﺔ إﱃ ﺗﻠﺴــﻜﻮب 3.5 ﻣـﱰ ﰲ ﻣﺮﺻﺪ أﺑﺎﳾ ﺑﻮﻳﻨـﺖ وﺗﻠﺴـﻜﻮﺑﺎت ﻣـﺎﺟﻼن ﺑﻘﻴﺎس 6.5 ﻧ وﻗﺪ ﻣﱰ ﴩت اﻟﻨﺘﺎﺋﺞ ﰲ ﻣﺠﻠـﺔ اﻟﺮﺳﺎﺋﻞ اﻟﻔﻠﻜﻴﺔ . ﻟﻘﺪ ﺗﻮﺻـﻞ اﻟﻔﺮﻳـﻖ ﻣـﻦ ﺧﻼل دﻣﺞ ﻫﺬه اﻷرﺻﺎد اﻟﺠﺪﻳﺪة ﻣﻊ اﻟﺒﻴﺎﻧﺎت اﻷرﺷـــﻴﻔﻴﺔ ﻟﻠـــﻨﺠﻢ J0705+0612 إﱃ أن ـــــــــــــــــــــ ــــــــــــــــ اﻟﻨﺠﻢ ﺗﻌـﺮض ﻟﻼﺣﺘﺠـﺎب ﻣﺆﻗﺘًـﺎ ﺑﻮاﺳـﻄﺔ ﺳﺤﺎﺑﺔ ﺿﺨﻤﺔ ﺑﻄﻴﺌـﺔ اﻟﺤﺮﻛـﺔ ﻣـﻦ اﻟﻐـﺎز . واﻟﻐﺒﺎر ﺗﻘﺪّر ا ﺴﺎﻓﺔ ﺑ اﻟﺴﺤﺎﺑﺔ واﻟـﻨﺠﻢ ﺑﺤﻮاﱄ ﻣﻠﻴﺎري ﻛﻴﻠـﻮﻣﱰ )1.2 ﻣﻠﻴـﺎ ( ر ﻣﻴـﻞ وﺑﻘﻄﺮ ﻳﻘﺎرب 200 ﻣﻠﻴـﻮن ﻛﻴﻠـﻮﻣﱰ ) 120 ﻣﻠﻴﻮن ﻣﻴﻞ .( ﺗﺸ اﻟﺒﻴﺎﻧﺎت إﱃ أن اﻟﺴـﺤﺎﺑﺔ ﻣﺮﺗﺒﻄﺔ ﺟﺎذﺑﻴﺎً ﺑﺠﺴﻢ ﺛـﺎﻧﻮي ﻳـﺪور ﺣـﻮل اﻟــﻨﺠﻢ ﰲ اﻷﻃــﺮاف اﻟﺨﺎرﺟﻴــﺔ ﻟﻨﻈﺎﻣــﻪ اﻟﻜـﻮﻛﺒﻲ . ﺑﻴﻨﻤـﺎ ﻻ ﺗـ ﺰال ﻃﺒﻴﻌـﺔ اﻟﺠﺴـﻢ اﻟﺜـﺎﻧﻮي ﻣﺠﻬﻮﻟـﺔ وﻟﻜﻨـﻪ ﻳﺠـﺐ أن ﻳﻜـﻮن ـــــــــــــــــــــــــــــــــــــ - ﺎﻳﻮﻣ ﻳﻮﻧﻴﻮ 2 0 2 6 ﻈﻬﺮ ﻫﺬا اﻟﺮﺳﻢ اﻟﺘﺨ ﻠﻲ ﺎً ﻗﺮﺻ اً ﻛﺒ ـ ﻣﻦ اﻟ ﻣﺤﺎﻃ ﺤﻄﺎم اﻟ ﻮﻛ ﺎً ﺴﺤﺎ ﺔ ﻛﺜ ﻔﺔ ﻣﻦ اﻟﻐ ﺎر واﻟﻐﺎز ﻤﺮأﻣﺎم ﻧ ﻢ . ـﺎف اﺳﺘﺨﺪم ﻓﺮﻖ ﻣﻦ ﻋﻠﻤﺎء اﻟﻔﻠﻚ ﻣﻄ اﻟ ﺼــﺮيﻋــﺎﻟﻲ اﻟﺪﻗــﺔ ـ ﺟ ﻤ ) ( ﻏﻮﺳــﺖ ــ ﻋﻠــﻰ ﺗﻠﺴــ ﻮبﺟ ﻤ و ﺳــﺎوث ــ اﻟــﺪوﻟﻲ اﻟﻤﻤــﻮل ﺟﺰ ــ ﻫــﻮ أﺣـﺪ أﺟــﺰاء ﻣﺮﺻــﺪ ﺟ ﻤ ﺎً ﻣــﻦ ﻗِﺒــﻞ ا ــﺔ ﻟﻤﺆﺳﺴــﺔ اﻷﻣﺮ ﻜ ﻟﻠﻌﻠﻮم ﺸﻐ واﻟﺬ ﻠﮫ ﻣﺨﺘ ﻧﻮﻳﺮﻻب ﻟﻘ ﺎسﺣﺮﻛﺔ اﻟﻐﺎزداﺧﻞ اﻟﺴﺤﺎ ﺔ . ﻘ ﺲﻓﻴﻬﺎ ﻋﻠﻤﺎء اﻟﻔﻠﻚﺣﺮ ﺎت اﻟﻐﺎزاﻟﺪاﺧﻠ ﺔ ﻟﻘﺮص ﻫﺬﻩ ﻫﻲ اﻟﻤﺮة اﻷوﻟﻰ اﻟ ــﺪورﺣـــﻮل ﺟﺴـــﻢ ﺛـــﺎﻧﻮي ـــﻢ ﻣـــﻨﺨﻔﺾ اﻟﻜﺘﻠــﺔ ﻣﺜــﻞ ﻮﻛـــﺐ أو ﻧ ﻘـــﺪ . ـــﺎت اﻟﻔﻮﺿــ مﻫـــﺬا اﻻﻛﺘﺸـــﺎف ﻟﻤﺤــﺔ ﻧـــﺎدرة ﻋـــﻦ اﻟﻌﻤﻠ ﻻ ﺗـــﺰال ﺗﺸـــ ـــﺔ اﻟـــ ﻮ ﺔ واﻟﺪ ﻨﺎﻣ ﻜ ﻞ اﻷﻧﻈﻤﺔ اﻟ ﻮﻛﺒ ﺔ ﻌﺪ ﻓ ة ﻃﻮ ﻠﺔ ﻣﻦ ﺗ ﻮ ﻨﻬﺎ . [International Gemini Observatory/NOIRLab/NSF/AURA/P. Marenfeld & M. Zamani]