Free Astronomy Magazine July-August 2023 ARABIC VERSION

The simplest explanation is that the misaligned discs are likely caused by the gravitational pull of two planets in slightly different orbital planes. Hubble is piecing together a holistic view of the architecture of the sys- tem. The discs may be proxies for planets that are lapping each other as they whirl around the star. It’s sort of like spinning two vinyl records at slightly different speeds. Sometimes the labels will match up but then one gets ahead of the other. “It does suggest that the two planets have to be fairly close to each other. If one was moving much faster than the other, this would have been no- ticed in earlier observations. It’s like two racing cars that are close to each other, but one slowly overtakes and laps the other,” said Debes. The sus- pected planets are located in a re- gion roughly the distance of Jupiter from our Sun. And the shadows com- plete one rotation around the star about every 15 years — the orbital period that would be expected at that distance from the star. Also, these two inner discs are in- clined by about five to seven degrees relative to the plane of the outer disc. This is comparable to the range of orbital inclinations inside our So- lar System. “This is right in line with typical Solar System-style architec- ture,” said Debes. The outer disc that the shadows are falling on may extend as far as sev- eral times the radius of our Solar Sys- tem’s Kuiper belt. This larger disc has a curious gap at twice Pluto’s aver- age distance from the Sun. This might be evidence for a third planet in the system. Any inner planets would be difficult to detect because their light would be lost in the glare of the star. Also, dust in the system would dim their reflected light. ESA’s Gaia space ob- servatory may be able to measure a wobble in the star if Jupiter-mass planets are tugging on it, but this would take years given the long or- bital periods. The TW Hydrae data are from Hub- ble’s Space Telescope Imaging Spec- trograph. The NASA/ESA/CSA James Webb Space Telescope’s infrared vi- sion may also be able to show the shadows in more detail.     ﻣﺠﻠﺔ FreeAstronomy ﺎﻟﻌﺮ ﺔ 24 أﺑﺴﻂ ﺗﻔﺴ ﻫﻮ أن اﻷﻗﺮاص ا ﺎﺋﻠﺔ ﻧﺎﺗﺠـﺔ ﻋﲆ اﻷرﺟﺢ ﻋﻦ ﻗـﻮة اﻟﺠﺎذﺑﻴـﺔ ﻟﻜـﻮﻛﺒ ﰲ ﻣﺴﺘﻮﻳﺎت ﻣﺪارﻳـﺔ ﻣﺨﺘﻠﻔـﺔ ﻗﻠـﻴﻼً . ﻳﻌﻤـﻞ ﺗﻠﺴﻜﻮب ﻫﺎﺑﻞ ﻋﲆ ﺗﺠ ﻤﻴـﻊ رؤﻳـﺔ ﺷـﺎﻣﻠﺔ ﻟﻬﻴﻜﻠﻴﺔ اﻟﻨﻈﺎم . ﻗﺪ ﺗﻜﻮن اﻷﻗـﺮاص ﺑﻤﺜﺎﺑـﺔ وﺳﻄﺎء ﻟﻠﻜﻮاﻛﺐ اﻟﺘﻲ ﺗﻠﺘﻒ ﺑﻌﻀﻬﺎ ﺑـﺒﻌﺾ أﺛﻨﺎء دوراﻧﻬﺎ ﺣﻮل اﻟﻨﺠﻢ . ان ذﻟـﻚ ﻳﺸـﺒﻪ إﱃ ﺣﺪ ﻣﺎ ﺗﺪوﻳﺮ أﺳﻄﻮاﻧﺔ ﻣﻦ اﻟﻔﻴﻨﻴﻞ ﺑ ـ ﴪﻋﺎت ﻣﺨﺘﻠﻔﺔ ﻗﻠﻴﻼً ﻓ ﻔﻲ ﺑﻌﺾ اﻷﺣﻴـﺎن ﺗﺘﻄـﺎﺑﻖ ا ﻠﺼﻘﺎت وﻟﻜﻦ ﺑﻌﺪ ذﻟﻚ ﻳﺘﻘﺪم أﺣﺪﻫﻤﺎ ﻋﲆ اﻵﺧــﺮ ، ﻳﻘـﻮل دﻳـﺒﺲ ": ذﻟـﻚ ﻳﺸـ إﱃ أن اﻟﻜﻮﻛﺒ ﻳﺠﺐ أن ﻳﻜﻮﻧﺎ ﻗﺮﻳﺒ إﱃ ﺣـﺪ ﻣـﺎ ﻣﻦ ﺑﻌﻀﻬﻤﺎ اﻟﺒﻌﺾ ﻟﻮ. ﻛﺎن أﺣ ﺪﻫﻤﺎ ﻳﺘﺤﺮك أﴎع ﺑﻜﺜ ﻣﻦ اﻵﺧﺮ ﻟﻜﺎن ﻗﺪ ﻟﻮ ﺣﻆ ﻫﺬا ﰲ اﻷرﺻـﺎد اﻟﺴـﺎﺑﻘﺔ إن. ذﻟـﻚ ﻣﺜـﻞ ﺳـﻴﺎرﺗﻲ ــــــ ﺳﺒﺎق ﻗﺮﻳﺒﺘ ﻣﻦ ﺑﻌﻀﻬﻤﺎ اﻟـﺒﻌﺾ ، ﻟﻜـﻦ إﺣـﺪاﻫﻤﺎ ﺗﺘﺨﻄـﻰ اﻷﺧـﺮى ﺑـﺒﻂء وﺗـﺪور . ﺣﻮﻟﻬﺎ ﺗﻮﺟﺪ اﻟﻜﻮاﻛﺐ ا ﺤﺘﻤﻠـﺔ ﰲ ﻣﻨﻄﻘـﺔ ﻋﲆ ﻣﺴﺎﻓﺔ ﻗﺮﻳﺒﺔ ﻣﻦ ا ﺴﺎﻓﺔ اﻟﺘﻲ ﺗﻔﺼـﻞ ﻛﻮﻛﺐ ا ﺸﱰي ﻣﻦ اﻟﺸﻤﺲ . وﺗﻜﻤﻞ اﻟﻈﻼل دورة واﺣ ﺪة ﺣﻮل اﻟﻨﺠﻢ ﻛﻞ 15 ﻋﺎﻣًـﺎ وﻫـﻲ اﻟﻔﱰة ا ﺪارﻳﺔ ا ﺘﻮﻗﻌﺔ ﻋﲆ ﺗﻠﻚ ا ﺴﺎﻓﺔ ﻣـﻦ اﻟﻨﺠﻢ . ﻳﻘـﻮل دﻳـﺒﺲ ": أﻳﻀًـﺎ ﻳﻤﻴـﻞ ﻫـﺬان اﻟﻘﺮﺻﺎن اﻟﺪاﺧﻠﻴﺎن ﺑﺤـﻮاﱄ 5 إﱃ 7 درﺟـ ﺎت ﺑﺎﻟﻨﺴﺒﺔ ﺴﺘﻮى اﻟﻘـﺮص اﻟﺨـﺎرﺟﻲ ﻫـﺬا و ﺪى ﻣﺸﺎﺑﻪ ا ﻴـﻮل ا ﺪارﻳـﺔ داﺧـﻞ ﻧﻈﺎﻣﻨـﺎ اﻟﺸﻤﴘ " . ﻫﺬا ﻳﺘﻤﺎﳽ ﺗﻤﺎﻣًﺎ ﻣﻊ اﻟﻬﻨﺪﺳـ ﺔ ا ﻌﻤﺎرﻳـﺔ اﻟ ﻨﻤﻮذﺟﻴـﺔ ﻋـﲆ ﻏـﺮار اﻟﻨﻈـﺎم اﻟﺸﻤﴘ ." ﻗﺪ ﻳﻤﺘﺪ اﻟﻘﺮص اﻟﺨﺎرﺟﻲ اﻟـﺬي ﺗﺴﻘﻂ ﻋﻠﻴﻪ اﻟﻈﻼل ﺑﻘﺪر ﻣﺎ ﻳﺼﻞ إﱃ ﻋ ﺪة أﺿﻌﺎف ﻧﺼﻒ ﻗﻄﺮ ﺣـﺰام ﻛـﺎﻳﱪ ﻟﻨﻈﺎﻣﻨـﺎ اﻟﺸﻤﴘ . ﻳﺤﺘﻮي ﻫﺬا اﻟﻘـﺮص اﻷﻛـﱪ ﻋـﲆ ﻓﺠﻮة ﻏﺮﻳﺒﺔ ﺗﺒﻠﻎ ﺿﻌﻒ ﻣﺘﻮﺳـﻂ ا ﺴـﺎﻓﺔ ﺑ ﺑﻠﻮﺗـﻮ واﻟﺸـﻤﺲ وﻫـﺬا ﻳـﺮﺟﺢ وﺟـﻮد ﻛﻮﻛﺐ ﺛﺎﻟ ، ﺚ ﺳﻴﻜﻮن ﻣﻦ اﻟﺼﻌﺐ اﻛﺘﺸـﺎف ﻛﻮاﻛﺐ داﺧﻠ ﻴﺔ ﻷن ﺿﻮءﻫﺎ ﺳﻴﻀﻴﻊ ﰲ وﻫﺞ اﻟﻨﺠﻢ ، ﻛﻤﺎ أن اﻟﻐﺒﺎر ﰲ اﻟﻨﻈﺎم ﻳﺨﻔﺖ اﻟﻀﻮء ا ﻨﻌﻜﺲ . ﻗﺪ ﻳﻜﻮن ﻣﺮﺻـﺪ ﻏ ﺎﻳـﺎ اﻟﻔﻀـﺎﺋﻲ ﻗﺎدراً ﻋﲆ ﻗﻴﺎس اﻟﺘﺬﺑﺬب ﰲ اﻟﻨﺠﻢ ﻟـﻮ ﻛـﺎن ﻠﻟ ﻜﻮاﻛﺐ ﻛﺘﻠﺔ ا ﺸـﱰي ﺗﺴـﺤﺒﻪ ﻟﻜـﻦ ﻫـﺬا ﺳ ﻴﺴـﺘﻐﺮق ﺳـﻨﻮات ﺑﺴـﺒﺐ ﻃــﻮل اﻟﻔـﱰة ا ﺪارﻳﺔ . إن ﺑﻴﺎﻧﺎت اﻟﻨﺠﻢ ﺗـﻲ دﺑﻠﻴـﻮ ﻫﻴـﺪرا ﺑﻮاﺳﻄﺔ ﻣﻄﻴﺎف ﺗﻠﺴﻜﻮب ﻫﺎﺑﻞ ﻣـﻊ رؤﻳـﺔ ﺗﻠﺴﻜﻮب ﺟﻴﻤﺲ وﻳـﺐ ﺗﺤـﺖ اﻟﺤﻤـﺮاء ﻗـﺪ ﺗﻈﻬﺮ اﻟﻈﻼل ﺑﻤﺰﻳﺪ ﻣﻦ اﻟﺘﻔﺎﺻﻴﻞ . ﻳﻮﻟﻴﻮ - ﺃﻏﺴﻄﺲ 2 0 2 3 ﻛﺸـﻔﺖ اﻟﺼـﻮراﻟﻤﻘﺎر ـﺔ ﻣـﻦ ﺗﻠﺴـ ﻮبﻫﺎﺑـﻞ اﻟﻔﻀـ ﺎ ﺗﻔﺼـﻞ ﺑ ﻨﻬـﺎ ﻋـﺪةﺳــﻨﻮات ﻋـﻦ ﻇ ﺋﻲ اﻟـ ـﺎن ﻋﻜـﺲاﺗﺠـﺎﻩ ﻋﻘـﺎر اﻟﺴـﺎﻋﺔ ﻋـ ﻗـﺮصﻣـﻦ اﻟﻐــﺎز ﺘﺤﺮ ﻠـ واﻟﻐ ﺎر ﻳﺤ ﻂ ﺎﻟﻨ ﻢ اﻟ ﺎﻓﻊ ﺗﻲدﻟ ﻠﻴﻮ ﻫ ﺪرا ﺣ ﺚ ﻈﻬﺮوﺟﮫ اﻷﻗﺮاص ﻤﺎ ﺗُﺮىﻣﻦ اﻷرض وﻫـﺬا ـﺔ ﺷـﺎﻣﻠﺔ ﻟﻤـﺎ ﻳﺤـﺪثﺣـﻮل اﻟـﻨ ﻢ ﻣـﻨﺢ ﻋﻠﻤـﺎء اﻟﻔﻠـﻚ رؤ . ﺗـﻢ اﻟﺘﻘﺎﻃﻬـﺎ ﺗُﻈﻬـﺮاﻟﺼـﻮرة اﻟ ﺴـﺮى اﻟـ ﻓـﻲﻋـﺎم 2016 ﻇـﻼً واﺣـﺪًا [A] ﺗﺸـ ﻞ ﺑﻮاﺳــﻄﺔ ﻗـﺮصداﺧﻠـﻲ ﻤﻴـﻞ ﻗﻠـ ﻼً إﻟـﻰ اﻟﻘـﺮصاﻟـ ـ ﺨﺎرﺟﻲو ﻤﻨـﻊ ﺿـﻮء اﻟﻨ ﻢ . ًـﺎ ﻇﻬـﺮﻣـﻦ ﻗـﺮصآﺧـﺮﻣﺘـﺪاﺧﻞ ﻤـﺎ ﺗـﻢ ﺗﺼـﻮﻳﺮﻩ ﻓـﻲ ﻋـﺎم ﻇﻼً ﺛﺎﻧ ﺗُﻈﻬﺮاﻟﺼﻮرة اﻟﻤﻮﺟﻮدة ﻋﻠﻰ اﻟ ﻤ 2021 . ـﺎن ﻓـﻲ اﻷﺻـﻞ اﻟﻘـﺮصاﻟـﺪاﺧﻠﻲ ﻣـﺎ ﺗﻢ ﺗﻤﻴـ ﻩ ﻌﻼﻣـﺔ [B] ﻓـﻲﻫـﺬا اﻟﻌـﺮ . ضاﻷﺧـ ﺗـﺪوراﻟﻈـﻼل ﺣـﻮل اﻟـﻨ ﻢ ﻤﻌـﺪﻻتﻣﺨﺘﻠﻔـﺔ ﻣﺜـﻞ ﻋﻘـﺎر اﻟﺴـﺎﻋﺔ . ﻣـﻦ اﻟ ﻮاﻛـﺐ ﻏـ إﻧﻬـﺎ دﻟﻴـﻞ ﻋﻠـﻰ اﺛﻨـ اﻟﻤﺮ ﺔ ﻗﺎﻣﺎ ﺴﺤﺐ اﻟﻐ ﺎرإﻟﻰﻣﺪاراﺗﻬﻤﺎ . ﺎ ﻫﺬا ﻳﺠﻌﻠﻬ ﺗﻤﻴﻞ ﻗﻠ ﻼً ﺎﺗﺠﺎﻩ . ﺎ ﻌﻀﻬ ﻫﺬﻩﺻﻮرة ﺎﻟﻀـﻮء اﻟﻤﺮ ـﻲ ﺗـﻢ اﻟﺘﻘﺎﻃﻬـﺎ ﺎﺳـﺘﺨﺪام ـﺎف اﻟﺘﺼـﻮﻳﺮ ﻣﻄ ﺎﻟﺘﻠﺴ ﻮب اﻟﻔﻀﺎﺋﻲ ﺗﻤ. اﻟﺘﻔﺎﺻﻴﻞ ﺖ إﺿﺎﻓﺔ اﻟﻠﻮن اﻻﺻﻄﻨﺎﻋﻲ ﻟﺘﺤﺴ .] NASA, ESA, J. Debes STScI [