Free Astronomy Magazine May-June 2025 ARABIC VERSION

observed withnofearoflightcon tamina- tionorvariability causedbyahoststar. Anditsshortrotationpe- riodofjust2.4hoursmakesit possible to survey very efficiently. PriortotheWebbobservations,SIMP 0136 had been studied exten- sively using ground-based observa- toriesandNASA’sHubbleandSpitzer space telescopes. “We already knew that it varies in brightness, and we were confident that there are patchy cloud layers that rotate in and out of view and evolve over time,” explained Allison McCarthy, doctoral student atBostonUniversityandleadauthor on a study published in The Astro- physical Journal Letters . “We also thought there could be temperature variations, chemical reactions, and possibly some effects of auroral ac- tivity affecting the brightness, but we weren’t sure.” To figure it out, the team needed Webb’sabilitytomeasureverypre- cise changes in brightness over a broad range of wavelengths. Using NIRSpec (Near-Infrared Spec- trograph), Webb captured thou- sands of individual 0.6- to 5.3- micronspectra—oneevery1.8sec- ondsovermorethanthreehoursas theobjectcompletedonefullrota- tion.Thiswasimmediatelyfollowed by an observation with MIRI (Mid- Infrared Instrument), which col- lected hundreds of spectroscopic measurements of 5- to 14-micron light—oneevery19.2seconds,over another rotation. The result was hundreds of detailed light curves, each showing the change in brightness of a very pre- cise wavelength (color) as different sidesoftheobjectrotatedintoview. “Toseethefullspectrumofthisob- ject change over the course of min- utes was incredible,” said principal investigator Johanna Vos, from Trin- ity College Dublin. “Until now, we onlyhadalittlesliceofthenear-in- frared spectrum from Hubble, and a few brightness measurements from Spitzer.” The team noticed almost immediately that there were several distinct light-curve shapes. At any given time, some wavelengths were growing brighter, while others were becoming dimmer or not changing much at all. A number of different factorsmustbeaffectingthebright- MAY-JUNE2025 ﻣﺠﻠﺔ FreeAstronomy ﺎﻟﻌﺮ ﺔ 41 ﻟﻠﺪراﺳﺔ ا ﻨﺸﻮرة ﰲ رﺳﺎﺋﻞ دورﻳﺔ اﻟﻔﻴﺰﻳﺎء اﻟﻔﻠﻜﻴﺔ، واﻟﺘﻲ ﺳﻠﻄﺖ اﻟﻀﻮء ﻋﲆ ا ﻟﻄﺒﻴﻌﺔ اﻟﺪﻳﻨﺎﻣﻴﻜﻴﺔ ﻟﻐـﻼف SIMP 0136 اﻟﺠـﻮي : " ﻋﻠﻤﻨﺎ ﺑﺘﻘﻠﺒﺎت ﺳﻄﻮﻋﻪ ورﺟﺤﻨـﺎ وﺟـﻮد ﺳﺤﺐ ﻣﺘﻘﻄﻌﺔ ﺗـﺪور وﺗﺘﻄـﻮر ﰲ ﻣﺠـﺎل . رؤﻳﺘﻨﺎ ﺗﻮﻗﻌﻨـﺎ أﻳﻀًـﺎ اﺧﺘﻼﻓـﺎت ﺣﺮارﻳـﺔ وﻛﻴﻤﻴﺎﺋﻴﺔ ورﺑﻤﺎ ﺗﺄ ﺛ ات ﺷﻔﻘﻴﺔ ﺗﺆﺛﺮ ﻋﲆ ﻫﺬا اﻟﺴـﻄﻮع ﻟﻜﻨﻨـﺎ ﻛﻨـﺎ ﺑﺤﺎﺟـﺔ ﻟﻘـﺪرة ﺗﻠﺴﻜﻮب ﺟـﻴﻤﺲ وﻳـﺐ ﻋـﲆ ﻗﻴـﺎس أدق ﺗﻐـ ات ا ﻟﺴـﻄﻮ ع ﻋـﱪ ﻃﻴ ـﻒ واﺳـﻊ ." ﻟﺘﺤﻘﻴـﻖ ذﻟـﻚ اﺳـﺘﺨﺪم اﻟﻔﺮﻳـﻖ ﻣﻄﻴـﺎف اﻷﺷﻌﺔ ﺗﺤﺖ اﻟﺤﻤﺮاء اﻟﻘﺮﻳﺒﺔ ﻧ ﻛﺎم ) ( ﻋﲆ ﻣﺘﻦ ﺗﻠﺴﻜﻮب ﺟﻴﻤﺲ وﻳﺐ اﻟﻔﻀﺎﺋﻲ وﻫﻲ أداة ﺑﺎﻟﻐﺔ اﻟﺤﺴﺎﺳﻴﺔ ﻗـﺎدرة ﻋـﲆ ﺗﺤﻠﻴـﻞ اﻟﻀﻮء ا ﻨﺒﻌﺚ ﺑﺪﻗﺔ ﻏ ﻣﺴﺒﻮﻗﺔ . اﻟﺘﻘﻂ ﻫﺬا ا ﻄﻴﺎف آﻻف اﻷﻃﻴﺎف اﻟﻔﺮدﻳـﺔ )0.6-5.3 ﻣﻴﻜ ـﺮون ( ﺑﻤﻌ ـﺪل ﻃﻴ ـﻒ ﻛ ـﻞ 1.8 ﺛﺎﻧﻴﺔ ﻷﻛﺜﺮ ﻣـﻦ ﺛـﻼث ﺳـﺎﻋﺎت ﺧـﻼل دوراﻧﻪ اﻟﻜﺎﻣﻞ . وﺗﻼه رﺻﺪ ﻓﻮري ﺑﺎﺳـﺘﺨﺪام أداة اﻷﺷـﻌﺔ ﺗﺤﺖ اﻟﺤﻤﺮاء ا ﺘﻮﺳﻄﺔ MIR اﻟﺘﻲ ﺟﻤﻌﺖ ﻣﺌﺎت اﻟﻘﻴﺎﺳﺎت اﻟﻄﻴﻔﻴﺔ )5-14 ( ﻣﻴﻜﺮون ﺑﻤﻌﺪل ﻗﻴﺎس ﻛﻞ 19.2 ﺛﺎﻧﻴﺔ ﻟﺪورة أﺧـﺮى . أﺳﻔﺮ ذﻟـﻚ ﻋـﻦ ﻣﺌـﺎت ﻣﻨﺤﻨﻴـﺎت اﻟﻀـﻮء اﻟﺘﻔﺼﻴﻠﻴﺔ، ﻳﻮﺿﺢ ﻛﻞ ﻣﻨﻬﺎ ﺗﻐـ ﺳـﻄﻮع ﻃـﻮل ﻣـﻮﺟﻲ ﻣﺤـﺪد ﻟﻠﻐﺎﻳـﺔ ﻣـﻊ دوران ﺟﻮاﻧﺐ اﻟﺠﺴﻢ ا ﺨﺘﻠﻔﺔ . ﻋﻠﻘﺖ اﻟﺒﺎﺣﺜﺔ اﻟﺮﺋﻴﺴﻴﺔ ﺟﻮاﻧﺎ ﻓـﻮس ﻣـﻦ ﻛﻠﻴﺔ ﺗﺮﻳﻨﻴﺘﻲ ﰲ دﺑﻠﻦ ﻛ: " ﺎﻧـﺖ رؤﻳـﺔ ﺗﻐـ اﻟﻄﻴﻒ اﻟﻜﺎﻣﻞ ﻟﻬﺬا اﻟﺠ ﺮم ﺧﻼل دﻗﺎﺋﻖ أﻣﺮ اً ﻣﺬﻫﻼً وﻛﺸﻒ ﻋﻦ ﺗﻔﺎﺻﻴﻞ ﻟﻢ ﻧﻜﻦ ﻗﺎدرﻳﻦ ﻋﲆ رؤﻳﺘﻬﺎ ﻣﻦ ﻗﺒﻞ . ﻣﺎ اﻣﺘﻠﻜﻨﺎه ﺳـﺎﺑ ﺎً ﻘ ﻣـﻦ ﺗﻠﺴـﻜﻮﺑ ﻫﺎﺑـﻞ ﻲ وﺳﺒﻴﺘﺰر ﻟﻢ ﻳﻜﻦ ﺳـﻮى ﺟـﺰء ﺿـﺌﻴﻞ ﻣـﻦ ﻃﻴﻒ اﻷﺷﻌﺔ ﺗﺤﺖ اﻟﺤﻤ ﺮاء اﻟﻘﺮﻳﺒﺔ وﺑﻌﺾ ﻗﻴﺎﺳﺎت اﻟﺴﻄﻮع وﴎﻋﺎن ﻣ ﺎ رﺻﺪ اﻟﻔﺮﻳﻖ أﺷـﻜﺎ ﻻً ﻣﻤﻴـﺰة ﻨﺤﻨﻴـﺎت اﻟﻀـﻮء ﺣﻴ ـﺚ ﺳﻄﻌﺖ ﺑﻌﺾ اﻷﻃﻮال ا ﻮﺟﻴﺔ ﺑﻴﻨﻤﺎ ﺧﻔﺘﺖ أﺧﺮى أو ﺑﻘﻴﺖ ﺛﺎﺑﺘﺔ ﻧﺴﺒﻴﺎً ﻣﻤـﺎ ﻳﺸـ إﱃ ﺗﻔﺎﻋﻞ ﻋﻮاﻣﻞ ﻣﺘﻌﺪدة ﰲ ﺗﻐ ات اﻟﺴﻄﻮع . ﺑﻔﻀﻞ ﻓﱰة دوراﻧﻪ اﻟﻘﺼ ة اﻟﺘﻲ ﻻ ﺗﺘﺠﺎوز أرﺑﻊ ﻳﺘﻴﺢ ﺳﺎﻋﺎت ﻫﺬا اﻟـﺠﺮم اﻟﺴﻤﺎ وي SIMP 0136 ﻣﺴـﺤﺎً ﻋﺎﱄ اﻟﻜﻔﺎءة وﻗﺪ ﺳﺒﻖ أن دُرِس ﻫﺬا اﻟ ﺠﺮم اﻟﻜﻮﻛﺒﻲ اﻟﻌﺎﺋﻢ ﺑﺤﺮﻳﺔ ﻋـﲆ ﻧﻄـﺎق واﺳـﻊ ﺑﻮاﺳﻄﺔ ﻣﺮاﺻﺪ أرﺿﻴﺔ وﺗﻠﺴﻜﻮﺑﻲ ﻫﺎﺑـﻞ وﺳﺒﻴﺘﺰر اﻟﻔﻀﺎﺋﻴ اﻟﺘﺎﺑﻌ ﻟ ـﻮﻛﺎﻟﺔ . ﻧﺎﺳﺎ ﺗﻘﻮل أﻟﻴﺴﻮن ﻣﻜـﺎرﺛﻲ ﻃﺎﻟﺒـﺔ اﻟـﺪﻛﺘﻮراه ﺑﺠﺎﻣﻌــﺔ ﺑﻮﺳــﻄﻦ وا ﺆﻟﻔــﺔ اﻟﺮﺋﻴﺴــﻴﺔ ﻣﺎﻳﻮ - ﻳﻮﻧﻴﻮ 2 0 2 5