Free Astronomy Magazine November-December 2022 ARABIC VERSION

ASTRO PUBLISHING 45 This planet is characterized as an ice giant due to the chemical make-up of its interior. Compared to the gas giants, Jupiter and Saturn, Neptune is much richer in elements heavier than hydrogen and helium. This is readily apparent in Neptune’s signa- ture blue appearance in Hubble Space Telescope im- ages at visible wavelengths, caused by small amounts of gaseous methane. Webb’s Near-Infrared Cam- era (NIRCam) images ob- jects in the near-infrared range from 0.6 to 5 mi- crons, so Neptune does not appear blue to Webb. In fact, the methane gas so strongly absorbs red and in- frared light that the planet is quite dark at these near- infrared wavelengths, ex- cept where high-altitude clouds are present. Such methane-ice clouds are prominent as bright streaks and spots, which reflect sunlight be- fore it is absorbed by methane gas. Images from other observatories, including the Hubble Space Tele- scope and the W.M. Keck Observa- evolving cloud fea- tures over the years. More subtly, a thin line of brightness circling the planet’s equator could be a visual signature of global atmospheric circulation that powers Neptune’s winds and storms. The atmosphere descends and warms at the equator, and thus glows at infrared wave- lengths more than the surrounding, cooler gases. Neptune’s 164-year orbit means its northern pole, at the top of this image, is just out of view for astronomers, but the Webb images hint at an intriguing bright- ness in that area. A previously- known vortex at the southern pole is evident in Webb’s view, but for continuous band of high-latitude clouds surrounding it. Webb also captured seven of Nep- tune’s 14 known moons. Dominat- ing this Webb portrait of Neptune is a very bright point of light sporting the signature diffraction spikes seen in many of Webb’s images, but this is not a star. Rather, this is Neptune’s large and unusual moon, Triton. Covered in a frozen sheen of con- densed nitrogen, Triton reflects an average of 70 percent of the sun- light that hits it. It far outshines Neptune in this image because the planet’s atmosphere is darkened by methane absorption at these near- infrared wavelengths. Tri- ton orbits Neptune in an unusual backward (retro- grade) orbit, leading as- tronomers to speculate that this moon was originally a Kuiper belt object that was gravitationally captured by Neptune. Additional Webb studies of both Triton and Neptune are planned in the coming year. The James Webb Space Tele- scope is the world’s premier space science observatory. Webb will solve mysteries in our solar system, look be- yond to distant worlds around other stars, and probe the mysterious struc- tures and origins of our universe and our place in it. Webb is an international program led by NASA with its partners, ESA (European Space Agency) and the tory, have recorded these rapidly the first time Webb has revealed a Canadian Space Agency.     NOVEMBER-DECEMBER 2022 ﻳﺘﻤﻴﺰ ﻫﺬا اﻟﻜﻮﻛﺐ ﺑﺄﻧﻪ ﻋﻤﻼق ﺟﻠﻴﺪي ﺑﺴﺒﺐ ﺗﺮﻛﻴﺒـ ﻪ اﻟﻜﻴﻤﻴـﺎﺋﻲ ا ﻟﺪاﺧﲇ ﺑﺎ ﻘﺎرﻧﺔ ﻣﻊ ﻋﻤﺎﻟﻘﺔ اﻟﻐﺎز ﻛﻮﻛﺐ ا ﺸﱰي وزﺣـﻞ ﻧﺒﺘـﻮن أﻏﻨﻰ ﺑﻜﺜ ﻣﻦ اﻟﻌﻨﺎﴏ اﻷﺛﻘﻞ ﻣﻦ اﻟﻬﻴﺪروﺟ واﻟﻬﻠﻴﻮم . ﻳﺘﻀـﺢ ﻫﺬا ﺑﺴﻬﻮﻟﺔ ﰲ ا ﻈﻬﺮ اﻷزرق ا ﻤﻴﺰ ﻟﻨﺒﺘﻮن ﰲ ﺻﻮر ﺗﻠﺴﻜﻮب ﻫﺎﺑﻞ اﻟﻔﻀﺎﺋﻲ ﻣﻦ ﺧﻼل اﻟﺮﺻﺪ ﻋﱪ أﻃﻮال ﻣﻮﺟﻴـﺔ ﻣﺮﺋﻴـﺔ ﻧﺎﺗﺠـﺔ ﻋـﻦ ﻛﻤﻴﺎت ﺻﻐ ة ﻣﻦ ﻏﺎز ا ﻴﺜﺎن . ﺗﺼــﻮّر ﻛ ـﺎﻣ ا ﺗﻠﺴــﻜﻮب وﻳ ـﺐ ﻟﻸﺷﻌﺔ ﺗﺤـﺖ اﻟﺤﻤـﺮاء اﻟﻘﺮﻳﺒـﺔ ) NIRCam ( أﺟـــﺮام ﰲ ﻧﻄـــﺎق اﻷﺷﻌﺔ ﺗﺤﺖ اﻟﺤﻤﺮاء اﻟﻘﺮﻳﺒ ﺔ ﻣﻦ ٠.٦ إﱃ ٥ ﻣﻴﻜﺮون ، ﻟﺬﻟﻚ ﻻ ﻳﻈﻬـﺮ ﻧﺒﺘﻮن ﺑﺎﻟﻠﻮن اﻷزرق ﺣﻴﺚ ، ﻳﻤﺘﺺ ﻏﺎز ا ﻴﺜﺎن اﻟﻀﻮء اﻷﺣﻤﺮ واﻷﺷﻌﺔ ﺗﺤﺖ اﻟﺤﻤﺮاء ﺑﻘﻮة ﺑﺤﻴﺚ ﻳﻜـﻮن اﻟﻜﻮﻛﺐ ﻣﻈﻠﻤًﺎ ﺗﻤﺎﻣًـﺎ ﻋﻨـﺪ ﻫـﺬه اﻷﻃـﻮال ا ﻮﺟﻴـﺔ ﻟﻸﺷـﻌﺔ ﺗﺤـﺖ اﻟﺤﻤﺮاء اﻟﻘﺮﻳﺒﺔ ﺑﺎﺳﺘﺜﻨﺎء اﻷﻣﺎﻛﻦ اﻟﺘـﻲ ﺗﻮﺟـﺪ ﻓﻴﻬـﺎ اﻟﺴـﺤﺐ ﻋـﲆ ارﺗﻔﺎﻋـﺎت ﻋﺎﻟﻴـﺔ . وﺗـﱪز ﻏﻴـﻮم ا ﻴﺜﺎن اﻟﺠﻠﻴﺪﻳﺔ ﻫـﺬه ﻋـﲆ ﺷـﻜﻞ ﺧﻄﻮط وﺑﻘﻊ ﻻﻣﻌﺔ ﺗﻌﻜﺲ ﺿﻮء اﻟﺸـﻤﺲ ﻗﺒـﻞ أن ﻳﻤﺘﺼــﻬﺎ ﻏـﺎز ا ﻴﺜﺎن . ﺻﻮر ﻣﻦ ا ﺮاﺻﺪ اﻷﺧﺮى ، ﺑﻤــﺎ ﰲ ذﻟــﻚ ﺗﻠﺴــﻜﻮب ﻫﺎﺑــﻞ اﻟﻔﻀﺎﺋﻲ و ﻣﺮﺻـﺪ ﻛﻴـﻚ ﺳـﺠﻠﺖ ﺑﴪﻋﺔ ﻫـﺬه اﻷﺷـﻜﺎل اﻟﻐﻴـﻮم ﴎﻳﻌـﺔ اﻟﺘﻄﻮر ﻋﲆ ﻣﺮ اﻟﺴﻨ . ﻳﻤﻜﻦ أن ﻳﻜﻮن ﺧﻂ اﻟﺴﻄﻮع اﻟﺮﻗﻴﻖ اﻟ ﺬي ﻳﺪور ﺣﻮل ﺧﻂ اﻻﺳﺘﻮاء ﻟﻠﻜﻮﻛﺐ ﺑﻤﺜﺎﺑﺔ ﺗﻮﻗﻴﻊ ﻣﺮﺋﻲ ﻟﺪورة اﻟﻐﻼف اﻟﺠﻮي اﻟﻌﺎ ﻴﺔ اﻟﺘﻲ ﺗﻨﺸﻂ اﻟﻐﻴﻮم واﻟﻌﻮاﺻﻒ ﻋﲆ . ﻧﺒﺘﻮن ﻳﻨﺨﻔﺾ اﻟﻐـﻼف اﻟﺠـﻮي وﻳـﺪﻓﺄ ﻋﻨ ـﺪ ﺧ ـﻂ اﻻﺳـﺘﻮاء ، وﺑﺎﻟﺘ ـﺎﱄ ﻳﺘــﻮﻫﺞ ﻋﻨــﺪ أﻃــﻮال ﻣﻮﺟــﺎت اﻷﺷﻌﺔ ﺗﺤﺖ اﻟﺤﻤﺮاء أﻛﺜـﺮ ﻣـﻦ اﻟﻐﺎزات ا ﺤﻴﻄﺔ اﻷﻛﺜﺮ ﺑﺮودة . إن ﻣﺪا ر ﻧﺒﺘﻮن اﻟﺬي ﻳﻤﺘﺪ ﻟـ ١٦٤ ﻋﺎﻣًﺎ ﻳﻌﻨﻲ أن اﻟﻘﻄـﺐ اﻟﺸـﻤﺎﱄ ﰲ اﻟﺠﺰء اﻟﻌﻠﻮي ﻟ ﻬﺬه اﻟﺼﻮرة ﺑﻌﻴﺪ ﻋﻦ رؤﻳﺔ ﻋﻠﻤﺎء اﻟﻔﻠﻚ ﻟﻜﻦ اﻟ ةﺼﻮر ﺗﺸ إﱃ ﺳﻄﻮع ﻣﺜـ ﻟﻼﻫﺘﻤـﺎم ﰲ ﺗﻠـﻚ ا ﻨﻄﻘـﺔ . ﺗﻈﻬـﺮ اﻟﺪواﻣـﺔ ا ﻌﺮوﻓﺔ ﺳﺎﺑﻘًﺎ ﰲ اﻟﻘﻄـﺐ اﻟﺠﻨـﻮﺑﻲ ﻣـﻦ ﻣﻨﻈـﻮر ﺗﻠﺴـﻜﻮب وﻳـﺐ ـــــــ وﻟﻜﻦ ﻟﻠﻤﺮة اﻷوﱃ ﻛﺸﻒ ﺗﻠﺴﻜﻮب وﻳﺐ ﻋﻦ ﻣﺠﻤﻮﻋﺔ ﻣﺴـﺘﻤﺮة ﻣـﻦ اﻟﺴـﺤﺐ ﻋـﲆ ﺧﻄـﻮط اﻟﻌ ـﺮض اﻟﻌﺎﻟﻴﺔ ا ﺤﻴﻄﺔ ﺑﻬﺎ . ﻛﻤﺎ اﻟﺘﻘﻂ ﺗﻠﺴﻜﻮب وﻳـﺐ ﺳـﺒﻌﺔ أﻗﻤﺎر ﻣﻦ أﺻﻞ ١٤ ﻗﻤـﺮا ﻣﻌﺮوﻓـﺎ ﻟﻨﻴﺒﺘﻮن . ﻳﺴﻴﻄﺮ اﻟ ﻫﺬه ﻋﲆ ﺼﻮرة ﻧﻘﻄﺔ ﻣﻀـﻴﺌﺔ ﺟـﺪًا ﻣـﻦ اﻟﻀـﻮء ﺗﺘﻤﻴﺰ ﺑﺎرﺗﻔﺎﻋﺎت اﻟﺤﻴـﻮد ا ﻤﻴـﺰة اﻟﺘﻲ ﺷﻮﻫﺪت ﰲ اﻟﻌﺪﻳﺪ ﻣﻦ ﺻـﻮر ﺗﻠﺴﻜﻮب وﻳﺐ ، وﻟﻜـﻦ ﻫـﺬا ﻟـﻴﺲ . ﻧﺠﻤًﺎ ﺑﺎﻷﺣﺮى ﻫﺬا ﻫﻮ ﻗﻤﺮ ﻧﺒﺘﻮن اﻟﻜﺒ وﻏ اﻟﻌﺎدي ، ﺗﺮﻳﺘﻮن . ﻳﺪور ﺗﺮﻳﺘﻮن ﺣﻮل ﻧﺒﺘﻮن ﰲ ﻣـﺪار ﻋﻜﴘ ﻏ ﻣﻌﺘﺎد ) ﺗﺮاﺟﻌﻲ ( ، ﻣﻤﺎ دﻓﻊ اﻟﻔﻠﻜﻴ إﱃ اﻟﺘﻜﻬﻦ ﺑﺄن ﻫـﺬا اﻟﻘﻤـﺮ ﻛــﺎن ﰲ اﻷﺻـﻞ ﺟﺴـﻤًﺎ ﰲ ﺣﺰام ﻛﺎﻳﱪ اﻟﺘﻘﻄـﻪ ﻧﺒﺘـﻮن ﻋـﻦ ﻃﺮﻳﻖ اﻟﺠﺎذﺑﻴﺔ . ﻣﻦ ا ﻘﺮر إﺟـﺮاء در اﺳﺎت إﺿﺎﻓﻴﺔ ﻟﻜﻞ ﻣﻦ ﺗﺮاﻳﺘﻮن ﻧﺒﺘﻮن و ﰲ اﻟﻌﺎم ا ﻘﺒﻞ . ﻳﻌﺘــﱪ ﺗﻠﺴـﻜﻮب ﺟـﻴﻤﺲ وﻳــﺐ ا ﺮﺻــﺪ اﻷول ﻟﻌﻠــﻮم اﻟﻔﻀــﺎء ﰲ اﻟﻌــﺎﻟﻢ واﻟـﺬي ﺳـﻴﺤﻞ اﻷﻟﻐـﺎز ﰲ ﻧﻈﺎﻣﻨﺎ اﻟﺸﻤﴘ ، وﻳﻨﻈـﺮ إﱃ ﻣـﺎ ﺑﻌﺪ اﻟﻌﻮاﻟﻢ اﻟﺒﻌﻴﺪة ﺣﻮل اﻟﻨﺠـﻮم اﻷﺧﺮى وﻳﺴﱪ اﻷﺟـﺮام اﻟﻐـﺎﻣﺾ وأﺻﻮل اﻟﻜﻮن وﻣﻜﺎﻧﻨﺎ ﻓﻴﻪ . ﺗﻠﺴﻜﻮب وﻳﺐ ﻫـ ﻮ ﺑﺮﻧـﺎﻣﺞ دوﱄ ﺗﻘﻮده وﻛﺎﻟﺔ ﻧﺎﺳﺎ ﻣـﻊ ﴍﻛﺎﺋﻬـﺎ وﻛﺎﻟﺔ اﻟﻔﻀﺎء اﻷوروﺑﻴـﺔ ووﻛﺎﻟـﺔ اﻟﻔﻀﺎء اﻟﻜﻨﺪﻳﺔ . ﻫــ ﻈﻬـﺮ ــﺐ ــﺎﻣ ا و ﺬا اﻹﺻــﺪارﻣــﻦ ﺻــﻮرة ﻟ ــﺔ ﻸﺷــﻌﺔ ﺗﺤــﺖ اﻟـــ ﻤﺮاء اﻟﻘﺮ (NIRCam) ﻟ ﻮﻛـــﺐ ﻧ ﺘـــﻮن ـــﺔ ﻟﻠ ﻮﻛـــﺐ ، ﺗـــﻢ ﺗﺼـــﻨ ﻒ اﻷﻗﻤـــﺎر اﻟﻤﺮ . ﻤﺘﻠـــﻚ ﻧ ﺘــﻮن ١٤ ﻗﻤــﺮا ﻣﻌﺮوﻓــﺎ ، وﺳـــ ﻌﺔ ﻣﻨ ﺎﻬــ ــﺔ ﻣﺮ ﻓـــﻲﻫــﺬﻩ اﻟﺼــﻮرة . ﺗﺮ ﺘـــﻮن اﻟﻨﻘﻄـــﺔ اﻟﻀـــﻮﺋ ﺔ اﻟﻼﻣﻌـــﺔ ـ ﻓـــﻲ اﻟـــ ﺠﺰء اﻟﻌﻠـــﻮي اﻷ ﺴـــﺮﻣـــﻦ ﻫـــﺬﻩ اﻟﺼــــﻮرة ﺗﺘﻔـــــــﻮق ﻛﺜــــــــ ًا ﻋﻠــــــــﻰ ﻧ ﺘـــــــﻮن ﻷن اﻟﻐــــــــﻼف اﻟــــــــ ـ ﺠﻮي ﻟﻠ ﻮﻛـــــــﺐ ﺼــــــــﺒﺢ داﻛﻨًــــــــﺎ ﻠﺘﻘﻄﻬﺎ ﺗﻠﺴ ﻮب و ﺐ ﺎﻣﺘﺼﺎص اﻟﻤ ﺜﺎن ﻋﻨﺪ اﻷﻃﻮال اﻟﻤﻮﺟ ﺔ اﻟ . ﺻـﻮرة ـﺎﻣ ا ﺑﻮاﺳـﻄﺔ ﺗﻠﺴـ ﻮب ـﺐ ﻟﻸﺷـﻌﺔ ﺗﺤـﺖ اﻟـ و ـ ﻤﺮ ـﺔ اء اﻟﻘﺮ (NIRCam) ﻟ ﻮﻛـــــــﺐ ﻧ ﺘــــــــﻮن ا ﻟﺘﻘﻄـــــــﺖ ﻓــــــــﻲ ١٢ ﻳﻮﻟﻴـــــــﻮ ٢٠٢٢ ﺗﻈﻬــــــــﺮ ﺣﻠﻘﺎت اﻟ ﻮﻛﺐ ﺸ ﻞ ﺎﻣﻞ ﻷول ﻣﺮة ﻣﻨﺬ أﻛ ﻣﻦ ﺛﻼﺛﺔ ﻋﻘﻮد . ﻣﺠﻠﺔ Astronomy ﺎﻟﻌﺮ ﺔ ٤٥ ﻧﻮﻓﻤ دﻳﺴﻤ 2022