Free Astronomy Magazine November-December 2025 ARABIC VERSION

resolution ALMA images at 1.3mm wavelengths, the team fitted a new model setup to the data, one that accountsforthedisk’sradius,width, and asymmetries, with an eccentric ring model that can alter its eccen- tricity with distance from the star. The best-fitting model pointed to a steep decline in eccentricity with distance, as predicted by dynamical theoriesofhowplanetscanshape debris disks, but as-yet seen any- where in the universe. This negative gradient offers clues abouthiddenplanets,currentlyun- seen by astronomers, orbiting Fo- malhaut.Thenewmodelsuggestsa massiveplanetorbitinginsideofFo- malhaut’sdiskmayhavesculptedits eccentricityprofileearlyintheex- trasolar system’s history. The un- usual shape of the debris disk may haveformedinthesystem’syouth, during the protoplanetary disk phase, and has remained this way for more than 400 million years, thanks to the continued push, and pull of this planet. In the second paper, led by Gradu- ate Student Jay Chittidi at Johns Hopkins University, the team ex- hausted the possibility that thering’s eccentricity is fixed with the distance from the star. “Although the shift in brightness fromthepericentersideofthedisk, nearesttothestar,totheapocenter side, furthest from the star, be- tweentheJWSTandALMAdata wasexpected,thepreciseshiftsthat we measured in the disk brightness and the ring’s width could not be explained by the old models,” said Jay. “Simply put: we couldn’t find a modelwithafixedeccentricitythat could explain these peculiar fea- tures in Fomalhaut’s disk. Compar- ing the old and new models, we are now able to better interpret this disk,andreconstructthehistoryand present state of this dynamic sys- tem.” Researchers hope this new model will be further tested with more ALMA observations, whichwere recently approved, “And hopefully we’ll find new clues that will help us uncover that planet!” adds Lovell. The team has sharedthe eccentricity model code devel- oped for this research to enable other astronomers to apply it to similarsystems.    NOVEMBER-DECEMBER2025 ﻌــﺮض ﻫــﺬا اﻟﻤﺸــﻬﺪ ــﺪة ﻟــ ﺻــﻮرة ﺟﺪ ـ ــﺎرﺣــﻮل اﻟــﻨ ﻢ اﻟﺴــﺎﻃﻊ ﻓــﻢ ﺤﻠﻘﺔ اﻟﻐ ـﺤ اﻟــ ﻮت اﻟﺘﻘﻄــﺖ ﺑﻮاﺳــﻄﺔ ــﺔ ﻣﺼــﻔﻮﻓﺔ أﺗﺎ ﺎﻣــﺎ اﻟﻤﻠ ﻤ وﺗﺤــﺖ ــﺔ اﻟﻤﻠ ﻤ اﻟﻜﺒــ ة أﻟﻤــﺎ ) .( ﺑ ﻨﻤــﺎ ﺗﻈﻬــﺮ اﻟﺼــﻮرة اﻟﺰرﻗــﺎء ﻓــﻲ اﻷﺳــﻔﻞ ﺻﻮرة ﺳﺎ ﻘﺔ اﻟﺘﻘﻄﻬﺎ ﺗﻠﺴ ﻮب ﻫﺎﺑﻞ اﻟﻔﻀﺎﺋﻲ اﻟﺘﺎﺑﻊ ﻟ ﻧ ﻮ ﺎﻟﺔ ﺎﺳﺎ وو ﺎﻟﺔ اﻟﻔﻀﺎء اﻷوروﺑ .ﺔ [ALMA (ESO/NAOJ/NRAO). Visible ligh image: the NASA/ESA Hubble Space Telescope ; Acknowledgement: A.C. Boley (University of Florida, Sagan Fellow), M.J. Payne, E.B. Ford, M. Shabran (University of Florida), S. Corder (North American ALMA Science Center, National Radio Astronomy Observatory), and W. Den (ALMA, Chile), P. Kalas, J. Gr ham, E. Chiang, E. Kite (University of California, Berkeley), M. Clampin (NASA Goddard Space Flight Center), M. Fitzgerald (Lawrence Livermore National Laboratory), and K. Stapelfeldt and J. Krist (NASA Jet Propulsion Laboratory)] أﺷﺎر اﻟﻨﻤﻮذج اﻷﻧﺴﺐ إﱃ اﻧﺨﻔـﺎض ﺣـﺎد ﰲ اﻻﻧﺤﺮاف ا ﺪاري ﻣﻊ ا ﺴﺎﻓﺔ ﻛﻤﺎ ﺗﻨﺒﺄت ﺑـﻪ اﻟﻨﻈﺮﻳــﺎت اﻟﺪﻳﻨﺎﻣﻴﻜﻴــﺔ ﻟﻜﻴ ﻔﻴــﺔ ﺗﺸــﻜﻴﻞ اﻟﻜﻮاﻛﺐ ﻷﻗﺮاص اﻟﺤﻄﺎم وﻟﻜﻨﻪ ﻟـﻢ ﻳ ﺮﺻـﺪ ﺣﺘﻰ اﻵن ﰲ أي ﻣﻜﺎن . ﰲ اﻟﻜﻮن ﻳ ﻘﺪم ﻫﺬا اﻟﺘ ﺪرج اﻟﺴﻠﺒﻲ أدﻟﺔً ﺣـﻮل ﻛﻮاﻛـﺐ ﺧﻔﻴﺔ ﻟﻢ ﻳﺮﺻﺪﻫﺎ اﻟﻔﻠﻜﻴﻮن ﺣﺎﻟﻴ ﺎً ﺗﺪور ﺣﻮل اﻟﻨﺠﻢ ﻮتﺤاﻟ ﻢﻓ وﻳﺸ اﻟﻨﻤﻮذج اﻟﺠﺪﻳـﺪ إﱃ أن ﻛﻮﻛﺒﺎً ﺎً ﺿﺨﻤ ﻳﺪور داﺧﻞ ﻗﺮصﻓ ﻮت ﺤاﻟ ﻢ رﺑﻤـﺎ ﻳﻜـﻮن ﻗـﺪ ﺳـﺎﻫﻢ ﰲ ﺗﻌـﺪﻳﻞ ﻣﻼﻣـﺢ اﻻﻧﺤﺮاف ا ﺪاري ﰲ وﻗﺖ ﻣﺒﻜـﺮ ﻣـﻦ ﺗـﺎرﻳﺦ اﻟﻨﻈﺎم ﺧﺎرج ا ﺠ ﻤﻮﻋـﺔ اﻟﺸﻤﺴـﻴ ﺔ ورﺑﻤـﺎ ﻳﻜﻮن اﻟﺸﻜﻞ ﻏ ا ﻌﺘﺎد ﻟﻘﺮص اﻟﺤﻄﺎم ﻗـﺪ ﺗﺸﻜﻞ ﰲ ﺑﺪاﻳﺔ اﻟﻨﻈﺎم ﺧﻼل ﻣﺮﺣﻠﺔ اﻟﻘـﺮص اﻟﻜﻮﻛﺒﻲ اﻷوﱄ وﻇﻞ ﻋﲆ ﻫﺬا اﻟﻨﺤﻮ ﻷﻛﺜﺮ ﻣﻦ 400 ﻣﻠﻴـﻮن ﺳـﻨﺔ ﺑﻔﻀـﻞ اﻟـﺪﻓﻊ واﻟﺠـﺬب ا ﺴﺘﻤﺮﻳﻦ ﻟﻬﺬا اﻟﻜﻮﻛﺐ . ﰲ اﻟﻮرﻗﺔ اﻟﺒﺤﺜﻴﺔ اﻟﺜﺎﻧﻴﺔ اﻟﺘﻲ ﻗﺎدﻫـﺎ ﻃﺎﻟـﺐ اﻟﺪراﺳﺎت اﻟﻌﻠﻴﺎ ﺟﺎي ﺗ ﺸﻴﺘﻴﺪي ﻣﻦ ﺟﺎﻣﻌـﺔ ﺟﻮﻧﺰ ﻫﻮﺑﻜﻨﺰ اﺳﺘﺒﻌﺪ اﻟﻔﺮﻳـﻖ اﺣﺘﻤ ﺎﻟﻴـﺔ أن ﻳﻜﻮن اﻧﺤﺮاف اﻟﺤﻠﻘﺔ ﺛﺎﺑﺘ ﺎً ﻣﻊ ا ﺴﺎﻓﺔ ﻣـﻦ اﻟﻨﺠﻢ . ﻋﲆ اﻟﺮﻏﻢ ﻣﻦ أن ا ﻧﺰﻳﺎح اﻟﺴﻄﻮع ﻣﻦ ﺟﺎﻧﺐ ﻣﺮﻛـﺰ اﻟﻘـﺮص اﻷﻗـﺮب إﱃ اﻟـﻨﺠﻢ إﱃ ﺟﺎﻧﺐ ﻣﺮﻛﺰه، اﻷﺑﻌﺪ ﻋﻦ اﻟﻨﺠﻢ، ﺑ ﺑﻴﺎﻧـﺎت ﺟﺎﻧﺐ ﻣﺮﻛﺰه اﻷﺑﻌﺪ ﻋﻦ اﻟـﻨﺠﻢ ﺑـ ﺑﻴﺎﻧـﺎت ﺗﻠﺴﻜﻮب ﺟـﻴﻤﺲ وﻳـﺐ وﻣﺮﺻـﺪ أ ـﺎ ﻛـﺎن ﺎ ﻣﺘﻮﻗﻌــ إﻻ أن اﻻﻧﺰﻳﺎﺣ ـﺎت اﻟﺪﻗﻴﻘــﺔ اﻟﺘــﻲ ﻗﺴﻨﺎ ﻫﺎ ﰲ ﺳﻄﻮع اﻟﻘﺮصوﻋﺮض اﻟﺤﻠﻘﺔ ﻟﻢ ﺗﺘﻤﻜﻦ اﻟﻨﻤـﺎذج اﻟﻘﺪﻳﻤـﺔ ﻣـﻦ ﺗﻔﺴـ ﻫﺎ ." " ﺑﺒﺴﺎﻃﺔ : ﻟﻢ ﻧﺘﻤﻜﻦ ﻣﻦ إﻳﺠـﺎد ﻧﻤـﻮذج ذي اﻧﺤﺮاف ﺛﺎﺑﺖ ﻳﻤﻜﻨﻪ ﺗﻔ ﺴ ﻫـﺬه اﻟﺴـﻤﺎت اﻟﻐﺮﻳﺒﺔ ﰲ ﻗﺮصﻓ . ﻮتﺤاﻟ ﻢ ﺑﻤﻘﺎرﻧﺔ اﻟﻨﻤﺎذج اﻟﻘﺪﻳﻤﺔ واﻟﺠ ﺪﻳﺪة أﺻﺒﺤﻨﺎ اﻵن ﻗﺎدرﻳ ﻦ ﻋـﲆ ﺗﻔﺴ وﻓﻬﻢ ﻫـﺬا اﻟﻘـﺮص ﺑﺸـﻜﻞ أﻓﻀـﻞ وإﻋـﺎدة ﺑﻨــﺎء ﺗـﺎرﻳﺦ وﺣﺎﻟـﺔ ﻫـﺬا اﻟﻨﻈـﺎم اﻟـﺪﻳﻨﺎﻣﻴ ﻜﻲ اﻟﺤﺎﻟﻴــﺔ ." ﻳﺄﻣـﻞ اﻟﺒـﺎﺣﺜﻮن أن ﻳ ﺨﺘﱪ ﻫﺬا اﻟﻨﻤﻮذج اﻟﺠﺪﻳﺪ ﺑﺸﻜﻞ أﻛـﱪ ﻣـﻦ ﺧﻼل ا ﺰﻳﺪ ﻣﻦ ﻋﻤﻠﻴـﺎت رﺻـﺪ ﻣﺮﺻـﺪ أ ـﺎ واﻟﺘﻲ ﺗﻤﺖ ـــــ واﻟﺘﻲ ﺗﻤﺖ ا ﻮاﻓﻘﺔ ﻋﻠﻴﻬﺎ ﻣـﺆﺧﺮًا . وﻳﻀـﻴﻒ ﻟﻮﻓﻴﻞ " : ﻧﺄﻣﻞ أن ﻧﺠﺪ أدﻟﺔ ﺟﺪﻳﺪة ﺗﺴﺎﻋﺪﻧﺎ ﰲ اﻛﺘﺸﺎف ﻫﺬا اﻟﻜﻮﻛﺐ ."! وﻗﺪ ﺷﺎرك اﻟﻔﺮﻳـﻖ ﺷﻴﻔﺮة ﻧﻤﻮذج اﻻﻧﺤﺮاف ا ﺪاري اﻟـﺬي ﻃُـﻮّر ﻟﻬﺬا اﻟﺒﺤﺚ ﻟﺘﻤﻜ ﻋﻠﻤﺎء اﻟﻔﻠﻚ اﻵﺧﺮﻳﻦ ﻣﻦ ﺗﻄﺒﻴﻘﻪ ﻋﲆ أﻧﻈﻤﺔ ﻣﻤﺎﺛﻠﺔ ﻳ . ﻌﺪ ﻫﺬا اﻟﺘﻘـﺪم ﺧﻄﻮة ﻣﻬﻤﺔ ﻧﺤﻮ ﻓﻬﻢ أﻋﻤﻖ ﻟﻜﻴﻔﻴﺔ ﺗﻄـﻮر أﻧﻈﻤ ﺔ اﻟﻜﻮاﻛﺐ ﺧﺎرج ا ﺠﻤﻮﻋﺔ اﻟﺸﻤﺴـﻴﺔ وﺧﺎﺻﺔ اﻷﻧﻈﻤﺔ اﻟﺘﻲ ﺗﺤﺘﻮي ﻋـﲆ أﻗـﺮاص ﺣﻄﺎم ﻏ اﻋﺘﻴﺎدﻳﺔ ﻣﺜﻞ ﻓ ﻳﺄﻣـﻞ و ﻮتﺤـ اﻟ ﻢ اﻟﻔﺮﻳ ـﻖ أن ﻳﺴـﻬﻢ ﻫـﺬا اﻟﻌﻤ ـﻞ ﰲ ﺗﺤﻔﻴ ـﺰ دراﺳﺎت ﻣﺴﺘﻘﺒﻠﻴﺔ ﺣـﻮل ﺗﻄـ ﻮر اﻷﻗـﺮاص اﻟﻜﻮﻛﺒﻴﺔ وﺗﻮﺳﻴﻊ ﻓﻬﻤﻨﺎ ﻟﻄﺒﻴﻌـﺔ اﻷﻧﻈﻤـﺔ اﻟﻨﺠﻤﻴﺔ اﻟﺸﺎﺑ ﺔ وا ﻌﻘﺪة ﰲ ﻣﺠﺮﺗﻨﺎ . ﻧﻮﻓﻤﺒﺮ - ﺩﻳﺴﻤﺒﺮ 2 0 2 5