Free Astronomy Magazine November-December 2025 ARABIC VERSION

ancient debris disk of unevenbrightness. Thediskisclosertothestar inthesouth,wherethediskis wider and fainter, and further from the star in the north, where the disk isnarrowerandbrighter.Thedotted ring shows the possible orbit of a planet implied by Lovell et al. As- tronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) have made the highest res- olution image to date, revealingnewinsightsintotheunusuala nd mys- terious architecture ofthedebrisdisk encircling Fomalhaut, oneofthebrightestandmost well-studied stars in our cosmic neighborhood.Debrisdisksarevast beltsofdustandrockybodies,simi- lar to our Solar System’s asteroid belt—but much larger. The lopsidedness (or eccentricity) of Fomalhaut’s disk has fascinated as- tronomers for nearly two decades. An international research team, led by astronomers at the Center for As- trophysics | Harvard & Smithsonian and Johns Hopkins University, pub- lished two papers analyzing these new observations in The Astrophysi- cal Journal/The Astrophysical Jour- nal Letters . They have now found thatFomalhaut’sdiskisnotjustec- c e n - tric—its eccentricity changes with distancefromthe star.Unlikeprevious models assumingauniform or “fixed” eccentricity, their new data-driven model shows that thedisk’sshapegrowslessstretched (or less eccentric) the farther a seg- ment is from Fomalhaut. This mor- phology is known as a negative eccentricity gradient. You can imag- ine the offsets between the star and the ring’s center, much like Saturn’s rings, if Saturn wasn’t sitting neatly in the middle. “Our observations show, for thefirsttime,thatthedisk’seccentricit y isn’t constant,” said lead author of one of the papers, Joshua Bennett Lovell, a Submillimeter Array Fel- low with the Harvard-Smithsonian Center for Astrophysics. “It steadily drops off with distance, a finding that has never before been conclu- sively demonstrated in any debris disk.” Lovell is also an ALMA Ambas- sador with the U.S. National Science Foundation National Radio Astron- omy Observatory’s North American ALMAScienceCenter.Usinghigh- NOVEMBER-DECEMBER2025 ﻣﺠﻠﺔ FreeAstronomy ﺎﻟﻌﺮ ﺔ 45 اﻟﻘﺮص ـأﻗ ﺮب إﱃ اﻟﻨﺠﻢ ﰲ اﻟ ﺠﻨﻮب ﺣﻴﺚ ﻳﻜـﻮن اﻟﻘـﺮص أﻋـﺮض وأﺧﻔﺖ وأﺑﻌﺪ ﻋﻦ اﻟـﻨﺠﻢ ﰲ اﻟﺸـﻤﺎل ﺣﻴـﺚ ﻳﻜﻮن اﻟﻘﺮص أﺿﻴﻖ وأﻛﺜﺮ ﺳـﻄﻮﻋ ﺗ. ﺎُ ﻈﻬـﺮ اﻟﺤﻠ ﻘﺔ ا ﻨﻘﻄﺔ ا ﺪار ا ﺤﺘﻤﻞ ﻟ ﻠﻜﻮﻛﺐ اﻟـﺬي اﻓﱰﺿﻪ ﻟﻮﻓﻴﻞ وآﺧﺮون وﻗـﺪ اﻟـﺘﻘﻂ ﻋﻠﻤـﺎء اﻟﻔﻠﻚ ﺑﺎﺳﺘﺨﺪام ﻣﺼﻔﻮﻓﺔ أﺗﺎﻛﺎﻣـﺎ ا ﻟﻜﺒـ ة ا ﻠﻴﻤﱰﻳﺔ وﺗﺤﺖ ا ﻠﻴﻤﱰي أ ﺎ) ( أﻋﲆ ﺻـ ﻮرة دﻗﺔ ﺣﺘﻰ اﻵن ﻛﺎﺷﻔ ﻋﻦ رؤى ﺟﺪﻳﺪة ﺣﻮل اﻟﺒﻨﻴﺔ ﻏ اﻟﻌﺎدﻳﺔ واﻟﻐﺎﻣﻀ ﺔ ﻟﻘﺮص اﻟﺤﻄﺎم ا ﺤﻴﻂ ﺑﻔﻢ اﻟﺤﻮت أﺣﺪ أ ﻊ اﻟﻨ وأﺳﻄﻊ ﺠـﻮم وأﻛﺜﺮﻫﺎ دراﺳﺔً ﰲ ﺟﻮارﻧﺎ اﻟﻜـﻮﻧﻲ . أﻗـﺮاص وأﻛﺜﺮﻫﺎ ﺔً ـ دراﺳ ﻮارﻧﺎ ـﰲ ﺟ اﻟﻜﻮﻧﻲ . أﻗﺮاص اﻟﺤﻄﺎم ﻫﻲ أﺣﺰﻣﺔ ﺿﺨﻤﺔ ﻣﻦ اﻟﻐﺒﺎر واﻷﺟﺴﺎم اﻟﺼﺨﺮﻳﺔ ﺗﺸﺒﻪ ﺣﺰام اﻟﻜﻮﻳﻜﺒﺎت ﰲ ﻧﻈﺎﻣﻨﺎ اﻟﺸﻤﴘ وﻟﻜﻨﻬـﺎ أﻛﱪ ﺑ ﻜﺜ وﻗـﺪ أﺛـﺎر اﺧـﺘﻼل ) أو اﻧﺤـﺮا ( ف ﻗﺮص ﻓﻢ اﻟﺤﻮت ﻓﻀـﻮل ﻋﻠﻤـﺎء اﻟﻔﻠـﻚ ـﺎ ﻳﻘﺮب ﻣﻦ ﻋﻘﺪﻳﻦ ﻣﻦ اﻟـﺰﻣﻦ ـﻧـ. ﴩ ﻓﺮﻳـﻖ ﺑﺤﺜﻲ دوﱄ ﺑﻘﻴﺎدة ﻋﻠﻤـﺎء ﻓﻠـﻚ ﻣـﻦ ﻣﺮﻛـﺰ اﻟﻔﻴﺰﻳﺎء اﻟﻔﻠﻜﻴﺔ | ﻫﺎرﻓـﺎرد وﺳﻤﻴﺜﺴـﻮﻧﻴﺎن وﺟﺎﻣﻌﺔ ﺟـﻮﻧﺰ ﻫـﻮﺑﻜﻨﺰ ورﻗﺘـ ﺑﺤﺜﻴﺘـ ﺗ ﺤﻠﻼن ﻫـﺬه ا ﻼﺣﻈـﺎت اﻟﺠﺪﻳـﺪة ﰲ ﻣﺠﻠـﺔ اﻟﻔﻴﺰﻳﺎء اﻟﻔﻠﻜﻴـﺔ / رﺳـﺎﺋﻞ ﻣﺠﻠـﺔ اﻟﻔﻴﺰﻳـﺎء ﻟﻔا ﻠﻜﻴﺔ وﻗﺪ وﺟﺪوا اﻵن أن ﻗﺮص ﻓ ﻮت ﺤاﻟ ﻢ ﻟﻴﺲ ﻣﺮﻛﺰﻳ ﺎً ﺑﺸﻜﻞ ﻣﺘﻤﺎﺛﻞ إذ ﻳﺘ ﻐ اﻧﺤﺮاﻓﻪ ﻣﻊ ا ﺴﺎﻓﺔ ﻣﻦ اﻟﻨﺠﻢ وﻋﲆ ﻋﻜـﺲ اﻟ ﻨﻤـﺎذج اﻟﺴﺎﺑﻘﺔ اﻟﺘـﻲ ﺗﻔـﱰض اﻧﺤﺮاﻓـ ﺎً أو اً ﻣﻮﺣـﺪ ﻳ" ﺎً ﺛﺎﺑﺘ " ﻈﻬﺮ ﻧﻤﻮذﺟﻬﻢ اﻟﺠﺪﻳﺪ اﻟﻘـﺎﺋﻢ ﻋـﲆ " ﺎً ﺛﺎﺑﺘ " ﻬﺮ ـﻈﻳ ﻧﻤﻮذﺟﻬﻢ اﻟﺠﺪﻳﺪ اﻟﻘﺎﺋﻢ ﻋﲆ ﺒﻴـاﻟ ﺎﻧﺎت أن ﺷ ﻜﻞ ـ ا ﻟﻘﺮص ﻳﺼﺒﺢ أﻗﻞ ﺗﻤﺪد اً أﻗﻞ أو) اﻧﺤﺮاﻓ ( ﺎً ﻛﻠﻤﺎ اﺑﺘﻌﺪت اﻟﻘﻄﻌـﺔ ﻋﻦ ﻓﻢ اﻟﺤﻮت . ﻳُﻌﺮف ﻫﺬا اﻟﺸﻜﻞ ﺑﺎﺳﻢ ﺗﺪرج اﻻﻧﺤﺮاف اﻟﺴﺎﻟﺐ . ﻳﻤﻜﻨﻚ ﺗﺨﻴﻞ اﻹزاﺣﺎت ﺑ اﻟﻨﺠﻢ وﻣﺮﻛﺰ اﻟﺤﻠﻘﺔ ﻣﺜﻞ ﺣﻠﻘﺎت زﺣﻞ ﻟﻮ ﻟﻢ ﻳﻜﻦ زﺣﻞ ﻳﻘﻊ ﰲ ا ﻨﺘﺼﻒ . ﻗﺎل ﺟﻮﺷﻮا ﺑﻴﻨﻴﺖ ﻟﻮﻓﻴﻞ اﻟﺒﺎﺣﺚ اﻟﺮﺋﻴ ﴘﰲ ـ إﺣﺪى اﻟﺪراﺳﺎت وﻫﻮ زﻣﻴﻞ ﰲ ﻣﺼﻔﻮﻓﺔ دون ا ﻠﻴﻤــﱰ ﺑﻤﺮﻛــﺰ ﻫﺎرﻓــﺎرد ﺳﻤﻴﺜﺴــﻮﻧﻴﺎن ﻟﻠﻔﻴﺰﻳﺎء اﻟﻔﻠﻜﻴﺔ ﻈﻬﺮ ﺗ : " أرﺻﺎدﻧﺎ ل ﻣﺮة وﻷو أن اﻧﺤﺮاف اﻟﻘﺮص ﻟـﻴﺲ ﺛﺎﺑﺘًـﺎ ." وأﺿـﺎف : " إﻧـﻪ ﻳﺘﻨــﺎﻗﺺ ﺑﺜ ﺒـﺎت ﻣـﻊ ا ﺴـﺎﻓﺔ وﻫـﻮ اﻛﺘﺸﺎف ﻟﻢ ﻳ ﺜﺒﺖ ﻗـﻂ ﺑﺸـﻜﻞ ﻗـﺎﻃﻊ ﰲ أي ﻗﺮص ﺣﻄﺎم ." ﻟﻮﻓﻴﻞ ﻫﻮ أﻳﻀ ﺳﻔ ﺎً ﺮﺻﺪ ا ﻟﺪى أ ﺎ ﺮﺻﺪ اﻟﻮ ﻃﻨﻲ ﻟﻌﻠﻢ اﻟﻔﻠﻚ اﻟﺮادﻳـﻮي اﻟﺘﺎﺑﻊ ﻠﻟ ﻤﺆﺳﺴﺔ اﻟﻮﻃﻨﻴﺔ ﻟﻠﻌﻠﻮم اﻷﻣﺮﻳﻜﻴﺔ ﰲ ﻣﺮﻛﺰ أ ﺎ اﻟﻌﻠﻤﻲ ﻷﻣﺮﻳﻜﺎ اﻟﺸﻤﺎﻟﻴﺔ . ﺑﺎﺳﺘﺨﺪام ﺻـﻮر ﻣﺮﺻـﺪ أ ـﺎ ﻋﺎﻟﻴـﺔ اﻟﺪﻗـﺔ ﺑﺄﻃﻮال ﻣﻮﺟﻴﺔ ﺗﺒﻠـﻎ 1.3 ﻣـﻢ ﻗـﺎم اﻟ ﻔﺮﻳـﻖ ﺑﺘﻄﻮﻳﺮ ﻧﻤﻮذج ﺟﺪﻳﺪ ﻟﻠﺒﻴﺎﻧﺎت وﻫـﻮ ﻧﻤـﻮذج ﻳﺄﺧﺬ ﰲ اﻻﻋﺘﺒﺎر ﻧﺼﻒ ﻗﻄ ﺮ اﻟﻘﺮص وﻋﺮ ﺿﻪ وﻋﺪم ﺗﻤﺎﺛﻠﻪ ﻣﻊ ﻧﻤـﻮذج ﺣﻠﻘـﻲ ﻻ ﻣﺮﻛـﺰي ﻳﻤﻜﻨﻪ ﺗﻐﻴ اﻧﺤﺮاﻓﻪ ﻣﻊ ا ﺴﺎﻓﺔ ﻣﻦ اﻟﻨﺠﻢ . ﻧﻮﻓﻤﺒﺮ - ﺮ ﺩﻳﺴﻤﺒ 2 0 2 5