Free Astronomy Magazine May-June 2025 ARABIC VERSION

rtist’sconceptofastellarflarefromProxima Centauri.[NSF/AUI/NSFNRAO/S.Dagnello] multi-wavelength study using mil- limeter observations to uncover a new look at the physics of flares. Combining 50 hours of ALMA ob- servations using both the full 12- meter array as well as the 7-meter Atacama Compact Array (ACA), a total of 463 flare events were re- portedatenergiesrangingfrom 10 24 to 10 27 erg, and with a brief du- ration ranging from 3 to 16 sec-onds. “When we see the flares with ALMA, we see the electromagnetic radiation–the light in various wave- lengths. But looking deeper, this radio wavelength flaring is also giv- ing us a way to trace the properties of those particles and get a handle on what is being released from the star,” says MacGregor. To do so, the team characterized the star’s so- called flare frequency distributiontomapoutthenumberoffla resas afunctionoftheirenergy.Typically, the slope of this distribution tendsto follow a power law function: smaller (less energetic) flares occur more frequently, while larger, more energetic flares occur less regularly. Proxima Centauri experiences so many flares that the team detected many flares within each energy range. Furthermore, the team was able to quantify the asymmetry of the star’s highest energy flares, de- scribing how the flares’ decay phase was much longer than the initial burst phase. to study the millimeter-wavelength flare activity of Proxima Centauri. Proxima Centauri’s small size and strong magnetic field indicate that itsentireinternalstructureisconvec- tive (unlike the Sun, which has both convective and non-convective lay- ers), making the star much more ac- tive. Its magnetic fields become twisted, develop tension, and even- tually snap, sending streams of en- ergy and particles outward in whatisobservedasflares. “OurSun’sac- tivitydoesn’tremoveEarth’satmos- phereandinsteadcausesbeautiful aurorasbecausewehaveathickat- mosphere and a strongmagnetic field to protect our planet. But ProximaCentauri’sflaresaremuch morepowerful,andweknowithas rocky planets in the habitable zone. What are these flares doing to their atmospheres? Is there such a large fluxofradiationandparticlesthat the atmosphere is getting chemi- cally modified, or perhaps com- pletely eroded?” said MacGregor. Thisresearchrepresentsthefirst Radio and millimeter-wavelength observationshelpconstraintheen- ergies associated with these flares and their associated particles. MacGregor highlighted ALMA’s key role: “The millimeter flaring seems muchmorefrequent.It’sadifferent power law than we see at the opti- cal wavelengths. If we only look at optical wavelengths, we’re missing critical information. ALMA is theonly millimeter interferometer sen- sitive enough for these measure- ments.”     A رﺳــــــﻢ ﺗﺨ ﻠـــــــﻲ ﻟﻠﺘــــــﻮﻫﺞ اﻟﻨ ﻤــــــﻲ اﻟﺴـــــــﺮﻊ ﻣــــــﻦ ﺑﺮوﻛﺴـــــــ ﻤﺎ ﻗﻨﻄﻮروس [NSF/AUI/NSFNRAO/S.Dagnello] 27 ﺑﻘﻴﺎدة ﻛﻴﺎﻧﺎ ﺑ ﺗﻮن ﻣﻦ ﺟﺎﻣﻌﺔ ﻛﻮﻟـﻮرادو وﻣ ﻳﺪﻳﺚ ﻣﺎﻛﺠﺮﻳﺠﻮر ﻣﻦ ﺟﺎﻣﻌﺔ ﺟـﻮﻧﺰ ﻫﻮﺑﻜﻨﺰ ﺑﻴﺎﻧﺎت اﻷرﺷﻴﻒ وأرﺻﺎد ﻣﺮﺻﺪ أ ﺎ اﻟﺠﺪﻳﺪة ﻟﺪ راﺳـﺔ ﻧﺸـﺎط اﻟﺘـﻮﻫﺞ ﺑﻄـﻮل ا ﻮﺟﺔ ا ﻠﻴﻤﱰﻳﺔ ﰲ ﺑﺮوﻛﺴﻴﻤﺎ ﻗﻨﻄﻮروس . ﻳﺸ ﺻﻐﺮ ﺣﺠﻢ ﺑﺮوﻛﺴـﻴﻤﺎ ﻗﻨﻄـﻮروس وﻣﺠﺎﻟﻪ ا ﻐـ ـ ﻨﺎﻃﻴﴘ اﻟﻘـﻮي إﱃ أن ﺑﻨﻴﺘـﻪ اﻟﺪاﺧﻠﻴﺔ ﺑﺄﻛﻤﻠﻬﺎ ذات ﺣﻤﻞ ﺣـﺮاري ﻋـﲆ ) ﻋﻜﺲ اﻟﺸﻤﺲ، اﻟﺘﻲ ﺗﺘﻜﻮن ﻣـﻦ ﻃﺒﻘـﺎت ﺣﻤﻞ ﺣﺮاري وﻏ ﺣﻤﻞ ﺣﺮاري ﻣ ( ﻤﺎ ﻳﺠﻌﻞ اﻟﻨﺠﻢ أﻛﺜﺮ ﻧﺸﺎﻃًﺎ ﺑﻜﺜ ﺗ ﺼـﺒﺢ ﻣﺠﺎﻻﺗـﻪ ا ﻐﻨﺎﻃﻴﺴﻴﺔ ﻣﻠﺘﻮﻳﺔ وﺗﺘﻄﻮر إﱃ ﺗـﻮﺗﺮ ﺛـﻢ ـ ﺗﻨﻜـ ﴪﰲ اﻟﻨﻬﺎﻳـﺔ ﻣﺮﺳـﻠﺔ ﺗﻴـﺎرات ﻣـﻦ اﻟﻄﺎﻗﺔ واﻟﺠﺴﻴﻤﺎت إﱃ اﻟﺨﺎ رج ﻓﻴﻤﺎ ﻳُﻼﺣﻆ ﻋﲆ ﺷﻜﻞ ﺗﻮﻫﺠﺎت إن . ﻧﺸﺎط اﻟﺸـﻤﺲ ﻻ ﻳﺰﻳﻞ اﻟﻐﻼف اﻟﺠﻮي ﻟﻸرض ﺑﻞ ﻳﺴﺒﺐ ﺑـﺪﻻً ﻣﻦ ذﻟﻚ ﺷﻔﻘًﺎ ﺟﻤﻴﻼً ﻷن ﻟﺪﻳﻨﺎ ﻏﻼﻓًﺎً ﺎً ﺟﻮﻳـ ﺎ ًﺳﻤﻴﻜ وﻣﺠﺎﻻً ﻣﻐﻨﺎﻃﻴﺴﻴﺎً ﻗﻮﻳـﺎً ﻟﺤﻤﺎﻳـﺔ ﻛﻮﻛﺒﻨـــﺎ ﻟﻜ ــﻦ ﺗﻮ ﻫﺠــﺎت ﺑﺮوﻛﺴ ــﻴﻤﺎ ﻗﻨﻄﻮروس أﻗﻮى ﺑﻜﺜ وﻧﺤﻦ ﻧﻌﻠﻢ أ ن ﻟﺪﻳﻪ ﻛﻮاﻛــ ﺐ ﺻــﺨﺮﻳﺔ ﰲ ا ﻨﻄﻘــﺔ اﻟﺼــﺎﻟﺤﺔ . ﺤﻴﺎة ﻟﻠ ﻣﺎذا ﺗﻔﻌﻞ ﻫﺬه اﻟﺘﻮﻫﺠﺎت ﺑﻐﻼﻓﻬﺎ اﻟﺠﻮي؟ ﻫﻞ ﻳﻮﺟﺪ ﺗﺪﻓﻖ ﻛﺒ ﻣﻦ اﻹﺷـﻌﺎع واﻟﺠﺴـﻴﻤﺎت ﻟﺪرﺟـﺔ أن اﻟﻐـﻼف اﻟﺠــﻮي ﻳﺘﻌﺮض ﻛﻴﻤﻴﺎﺋﻲ أو رﺑﻤﺎ ﻳﺘﺂﻛﻞ ﺗﻤﺎﻣ "ﺎ؟ ﻗﺎل ﻣﺎﻛﺠﺮﻳﺠﻮر ﻳﻤﺜـﻞ ﻫـﺬا اﻟﺒﺤـﺚ أول دراﺳﺔ ﻣﺘﻌﺪدة اﻷﻃﻮال ا ﻮﺟﻴﺔ ﺑﺎﺳـﺘﺨﺪام أرﺻﺎد ا ﻠﻴﻤﱰ ﻟﻠﻜﺸﻒ ﻋـﻦ ﻧﻈـﺮة ﺟﺪﻳـﺪة ﻋﲆ ﻓﻴﺰﻳﺎء اﻟﺘﻮﻫﺠﺎت . ﺑﺪﻣﺞ 50 ﺳﺎﻋﺔ ﻣﻦ ﻋﻤﻠﻴـﺎت ﻣﺮﺻـﺪ أ ـﺎ ﺑﺎﺳﺘﺨﺪام ﻛﻞﱟ ﻣﻦ ا ﺼﻔﻮﻓﺔ اﻟﻜﺎﻣﻠﺔ اﻟﺘـﻲ ﻳﺒﻠﻎ ﻗﻄﺮﻫﺎ 12 اً ﻣـﱰ وﻣﺼـﻔﻮﻓﺔ أﺗﺎﻛﺎﻣـﺎ ا ﺪﻣﺠﺔ ا ﻟﺘﻲ ﻳﺒﻠﻎ ﻗﻄﺮﻫﺎ 7 أﻣﺘﺎر ﺗﻢ رﺻـﺪ 463 ﺣﺪﺛًﺎ ﻣﻦ اﻟﺘﻮﻫﺠﺎت ﻃﺎﻗـﺎت ﺗـﱰاوح ﻣ ـﻦ 1024 إﱃ 1027 إرج وﺑﻤ ـﺪة ﻗﺼـ ة ﺗﱰاوح ﻣﻦ 3 إﱃ 16 . ﺛﺎﻧﻴﺔ ﻳﻘﻮل ﻣﺎﻛﺠﺮﻳﺠﻮر " : ﻋﻨﺪﻣﺎ ﻧﺮى اﻟﺘﻮﻫﺠﺎت ﺑﺎﺳ ـﺘﺨﺪام ﻣﺮﺻ ـﺪ أ ـﺎ ﻧ ـﺮى اﻹﺷ ـﻌﺎع اﻟﻜﻬﺮوﻣﻐﻨﺎﻃ - ﻴﴘ اﻟﻀﻮء ﺑﺄﻃﻮال ﻣﻮﺟﻴﺔ - ﻣﺨﺘﻠﻔﺔ وﻟﻜﻦ ﺑﺎﻟﻨﻈ ﺮ ﺑﺸﻜﻞ أﻋﻤﻖ ﻓـﺈن ﻫﺬا اﻟﺘﻮﻫﺞ ﺑ ﻄﻮل ا ﻮﺟﺔ اﻟﺮادﻳﻮﻳﺔ ﻳﻤﻨﺤﻨﺎ أﻳﻀــ ﺎً ﻃﺮﻳﻘــﺔ ﻟﺘﺘﺒــﻊ ﺧﺼــﺎﺋﺺ ﺗﻠــﻚ اﻟﺠﺴﻴﻤﺎت وﻣﻌﺮﻓﺔ ﻣـﺎ ﻳـ ﺘﻢ إﻃﻼﻗـﻪ ﻣـﻦ اﻟﻨﺠﻢ ." ﻟﺘﺤﻘﻴﻖ ذﻟـﻚ وﺻـﻒ اﻟﻔﺮﻳـﻖ ﻣـﺎ ﻳُﺴﻤﻰ ﺑﺘﻮزﻳﻊ ﺗﺮددات اﻟﺘﻮﻫﺠﺎت اﻟﻨﺠﻤﻴﺔ ﻟﺮﺳـﻢ ﺧﺮﻳﻄـﺔ ﻟﻌـﺪ د اﻟﺘﻮﻫﺠـﺎت ﻛﺪاﻟـﺔ ﻟﻄﺎﻗﺘﻬﺎ . ﻳﺘﺠﻪ ﻋﺎدةً ﻣﻴﻞ ﻫـﺬا اﻟﺘﻮزﻳـﻊ إﱃ إﺗﺒﺎع داﻟﺔ ﻗﺎﻧﻮن اﻟﻘﻮة : ﺗﺤﺪث اﻟﺘﻮﻫﺠـﺎت اﻷﺻﻐﺮ ) اﻷﻗﻞ ﻃﺎﻗﺔ ( ﺑﺸـﻜﻞ أﻛﺜـﺮ ﺗـﻮاﺗﺮاً ﺑﻴﻨﻤﺎ ﺗﺤﺪث اﻟﺘﻮﻫﺠﺎت اﻷﻛﱪ واﻷﻛﺜﺮ ﻃﺎﻗﺔ ﺑﺸـﻜﻞ أﻗـﻞ اﻧﺘﻈﺎﻣًـﺎ . ﻳﺸـﻬﺪ ﺑﺮوﻛﺴـﻴﻤﺎ ﺳﻨﺘﻮري ﻋﺪدًا ﻛﺒ ًا ﻣﻦ اﻟﺘﻮﻫﺠﺎت ﻟﺪرﺟـﺔ أن اﻟﻔﺮﻳﻖ رﺻﺪ اﻟﻌﺪﻳـﺪ ﻣﻨﻬـﺎ ﺿـﻤﻦ ﻛـﻞ ﻧﻄﺎق ﻃﺎﻗﺔ ﻋﻼوة ﻋﲆ ذﻟﻚ ﺗﻤﻜـﻦ اﻟﻔﺮﻳـ ﻖ ﻣﻦ ﺗﺤﺪﻳﺪ ﻋﺪم ﺗ ﻨﺎﺳﻖ اﻟﺘﻮﻫﺠـﺎت اﻷﻋـﲆ ﻃﺎﻗﺔ ﻟﻠﻨﺠﻢ واﺻﻔ ﺎً ﻛﻴـﻒ ﻛﺎﻧـﺖ ﻣﺮﺣﻠـﺔ اﺿـﻤﺤﻼل اﻟﺘﻮﻫﺠـﺎت أﻃـﻮل ﺑﻜﺜـ ﻣـﻦ ﻣﺮﺣﻠـﺔ اﻻﻧﻔﺠـﺎر اﻷوﱄ . ﺗﺴـﺎﻋﺪ ﻋﻤﻠﻴـﺎت اﻟﺮﺻﺪ اﻟﺮادﻳﻮي وﻣﻮﺟﺎت اﻟﻄـﻮل ا ـﻮﺟﻲ ا ﻠﻴﻤﱰﻳﺔ ﰲ ﺗﺤﺪﻳﺪ اﻟﻄﺎﻗﺎت ا ﺮﺗﺒﻄﺔ ﺑﻬﺬه اﻟﺘﻮﻫﺠﺎت واﻟﺠﺴﻴﻤﺎت ا ﺮﺗﺒﻄﺔ ﺑﻬﺎ . ﻳﻘـﻮل ﻣـ ﺎﻛﺠﺮﻳﺠﻮر " : ﻳﺒـﺪو أن اﻟﺘـﻮﻫﺞ ا ﻠﻴﻤـﱰي أﻛﺜـﺮ ﺗـﻮاﺗﺮ ،اً إﻧـﻪ ﻗـﺎﻧﻮن ﻗـﻮة ﻣﺨﺘﻠﻒ ﻋﻤـﺎ ﻧـ ﺮاه ﻋﻨـﺪ اﻷﻃـﻮال ا ﻮﺟﻴـﺔ اﻟﻀـﻮﺋﻴﺔ و إذا ﻧﻈﺮﻧــﺎ ﻓﻘــﻂ إﱃ اﻷﻃـﻮال ا ﻮﺟﻴﺔ اﻟﻀﻮﺋﻴﺔ ﻓﺴﻨﻔﻘﺪ ﻣﻌﻠﻮﻣﺎت ﺑﺎﻟﻐـﺔ اﻷﻫﻤﻴﺔ . ﻣﻘﻴﺎس أ ﺎ ﻫﻮ ﻣﻘﻴـﺎس اﻟﺘـﺪاﺧﻞ ا ﻠﻴﻤﱰي اﻟﻮﺣﻴﺪ اﻟـﺬي ﻳﺘﻤﺘـﻊ ﺑﺤﺴﺎﺳـﻴﺔ ﻛﺎﻓﻴﺔ ﻹﺟﺮاء ﻫﺬه اﻟﻘﻴﺎﺳﺎت ". ﻣﺎﻳﻮ - ﻳﻮﻧﻴﻮ 2 0 2 5