Free Astronomy Magazine January-February 2024 ARABIC VERSION

leads the Webb Guaranteed Time Observation (GTO) program de- signed to help build a three-dimen- sional view of a hot Jupiter at- mosphere. “We know there is silica from Webb’s MIRI data alone, but we needed the visible and near-in- frared observations from Hubble for context, to figure out how large the crystals are.” Unlike mineral particles found in clouds on Earth, the quartz crystals detected in the clouds of WASP-17 b are not swept up from a rocky sur- face. Instead, they originate in the atmosphere itself. “WASP-17 b is ex- tremely hot – around 2,700 degrees Fahrenheit (1,500 degrees Celsius) – and the pressure where the quartz crystals form high in the atmos- phere is only about one-thousandth of what we experience on Earth’s surface,” explained Grant. “In these conditions, solid crystals can form directly from gas, without going through a liquid phase first.” Understanding what the clouds are made of is crucial for understanding the planet as a whole. Hot Jupiters like WASP-17 b are made primarily of hydrogen and helium, with small amounts of other gases like water vapor (H 2 O) and carbon dioxide (CO 2 ). “If we only consider the oxy- gen that is in these gases, and neg- lect to include all of the oxygen locked up in minerals like quartz (SiO 2 ), we will significantly underes- timate the total abundance,” ex- plained Wakeford. “These beautiful silica crystals tell us about the inven- tory of different materials and how they all come together to shape the environment of this planet.” Exactly how much quartz there is, and how pervasive the clouds are, is hard to determine. “The clouds are likely present along the day/night transition (the terminator), which is the region that our observations probe,” said Grant. Given that the planet is tidally locked with a very hot day side and cooler night side, it is likely that the clouds circulate around the planet, but vaporize when they reach the hotter day side. “The winds could be moving these tiny glassy particles around at thousands of miles per hour.”      25 ﻣﺠﻠﺔ FreeAstronomy ﺎﻟﻌﺮ ﺔ ﺗﻤﺜﻴﻞ ﻟ ﻌﺸﺮة ﻮاﻛﺐ ﻓﺌﺔ اﻟﻤﺸ ي اﻟﺴﺎﺧﻨﺔ اﻟﻤﻌﺮوﻓﺔ . اﻟﺼﻮرﻳﺠﺐ أن ﺗﺘﻨﺎﺳﺐ ﻣﻊ ﻌﻀﻬﺎ اﻟ ﻌﺾ . DHAT-P-12b ـﺎً أﺻـﻐﺮﻫﺎ ﺣ ﻤـﮫ ﺗﻘﺮ أن ـﻢ ﻮﻛــﺐ اﻟﻤﺸـ يﻓـﻲﺣـ ﺣ WASP-17b أﻛـ ﻮﻛـﺐ ﻓـﻲ اﻟﻌ ﻨﺔ ﻳ ﻠﻎ ﺿﻌﻒﺣ ﻤﮫ ﺗﻘﺮ ًﺎ ﺗﻢ . ﺗﻤﺜﻴﻞ اﻟ ﻮاﻛﺐ أ ﻀًﺎ ﻤ ﻤﻮﻋﺔ ﻣﻦ ﺧﺼﺎﺋﺺ اﻟﻐﻴﻮم اﻟﻤﺨﺘﻠﻔﺔ . - ﻳﻨﺎﻳﺮ ﻓﺒﺮﺍﻳﺮ 2 0 2 4 ﻟﻘـﺪ " ﻟﻌﺒـﺖ ﺑﻴﺎﻧـﺎت ﻫﺎﺑـﻞ ﰲ اﻟﻮاﻗـﻊ دور اً رﺋﻴﺴ ﻴًﺎ ﰲ ﺗﺤﺪﻳﺪ ﺣﺠـﻢ ﻫـﺬه اﻟﺠﺴـﻴﻤﺎت " أوﺿﺢ ا ﺆﻟﻒ ا ﺸـﺎرك ﻧﻴﻜـﻮل ﻟـﻮﻳﺲ ﻣـﻦ ﺟﺎﻣﻌﺔ ﻛﻮرﻧﻴﻞ ، اﻟﺬي ﻳﻘﻮد ﺑﺮﻧﺎﻣﺞ ﻣﺮاﻗﺒـﺔ اﻟــﺰﻣﻦ ا ﻀـﻤﻮن وﻳ ـﺐ (GTO) ا ﺼـﻤﻢ ﻟﻠﻤﺴﺎﻋﺪة ﰲ ﺑﻨﺎء رؤﻳﺔ ﺛﻼﺛﻴﺔ اﻷﺑﻌﺎد ﻟﻠﻜ ﻮن ﻟﻠﻐـﻼف اﻟﺠـﻮي ﻟﻔﺌـﺔ ﻛـﺐ اﻜﻮ اﻟ اﻟﻨﺠﻤﻴـﺔ ا ﺸﱰي اﻟﺤﺎر ." ﻧﺤﻦ ﻧﻌﻠﻢ ﺑﻮﺟﻮد اﻟﺴـﻴﻠﻴﻜﺎ ﻣﻦ ﺑﻴﺎﻧﺎت أداة ( ﻣ ي ) اﻟﺨﺎﺻﺔ ﺑ ﺘﻠﺴـﻜﻮب وﻳﺐ ﻟﻜﻨﻨﺎ ﻛﻨﺎ ﺑﺤﺎﺟـﺔ إﱃ ﻋﻤﻠﻴـﺎت اﻟﺮﺻـﺪ ا ﺮﺋﻴﺔ واﻷﺷﻌﺔ ﺗﺤﺖ اﻟﺤﻤﺮاء اﻟﻘﺮﻳﺒـﺔ ﻣـﻦ ﺗﻠﺴﻜﻮب ﻫﺎﺑﻞ أﺟﻞ ﻣﻦ ا ﻘﺎرﻧﺔ ﻌﺮﻓﺔ ﻣﺪى ﺣﺠـﻢ اﻟﺒﻠـﻮرات ". ﻋـﲆ ﻋﻜـﺲ اﻟﺠﺰ ﻳﺌـﺎت ا ﻌﺪ ﻧﻴﺔ ا ﻮﺟﻮدة ﰲ اﻟﺴﺤﺐ ﻋﲆ اﻷرض ﻓﺈن ﺑﻠﻮرات اﻟﻜﻮارﺗﺰ ا ﻜﺘﺸﻔﺔ ﰲ ﺳﺤﺐ WASP- 17 b ﻟﻢ ﻳﺘﻢ اﻧﺘ ﺸﺎﻟﻬﺎ ﻣﻦ ﺳـﻄﺢ ﺻـﺨﺮي . وﺑﺪﻻ ﻣﻦ ذﻟﻚ ﻓﺈﻧﻬﺎ ﺗﻨﺸﺄ ﰲ اﻟﻐﻼف اﻟﺠـﻮي ﻧﻔﺴﻪ . وأوﺿﺢ ﺟﺮاﻧـﺖ " : إن WASP-17 b - ﺣﺎر ﻟﻠﻐﺎﻳﺔ ﺣﻮاﱄ 2700 درﺟﺔ ﻓﻬﺮﻧﻬﺎﻳـﺖ ـــ ) 1500 درﺟـﺔ ﻣﺌﻮﻳـﺔ (- واﻟﻀــﻐﻂ ﺣﻴـﺚ ﺗﺘﺸﻜﻞ ﺑﻠـﻮرات اﻟﻜـﻮارﺗﺰ ﻋﺎﻟﻴـ ﺎً ﰲ اﻟﻐـﻼف اﻟﺠﻮي ﻻ ﻳﺘﺠﺎوز واﺣﺪ اً ﻣﻦ أﻟﻒ ﻣﻤﺎ ﻧﻌﺮﻓـﻪ ﻋﲆ ﺳﻄﺢ اﻷرض ." " ﰲ ﻫﺬه اﻟﻈﺮوف ﻳﻤﻜﻦ أن ﺗﺘﺸﻜﻞ ا ﻟﺒﻠـﻮرات اﻟﺼـﻠﺒﺔ ﻣﺒـﺎﴍة ﻣـﻦ اﻟﻐﺎز دون ا ﺮور ﺑﻤﺮﺣﻠـﺔ ﺳـﺎﺋﻠﺔ أوﻻ ". إن ﻓﻬﻢ ﻣﻜﻮﻧﺎت اﻟﻐﻴﻮم أﻣﺮ ﺑﺎﻟﻎ اﻷﻫﻤﻴﺔ ﻟﻔﻬﻢ اﻟﻜﻮﻛﺐ ﻛﻜﻞ . إن ﻛﻮاﻛﺐ ا ﺸﱰي اﻟﺴـﺎﺧﻨﺔ ﻣﺜـﻞ WASP- 17 b ﺗﺘﻜﻮن ﺑﺸﻜ ﻞ أﺳﺎﳼﻣﻦ اﻟﻬﻴﺪروﺟ واﻟﻬﻴﻠﻴﻮم ﻣﻊ ﻛﻤﻴﺎت ﺻﻐ ة ﻣـﻦ اﻟﻐـﺎزات اﻷﺧﺮى ﻣﺜﻞ ﺑﺨﺎر ا ﺎء ) H2O ( وﺛﺎﻧﻲ أﻛﺴﻴﺪ اﻟﻜﺮﺑ ـﻮن ) CO2 ( وأوﺿـﺢ وﻳﻜﻔ ـﻮرد " : إذا أﺧﺬﻧﺎ ﰲ اﻻﻋﺘﺒﺎر ﻓﻘﻂ اﻷﻛﺴﺠ ا ﻮﺟـﻮد ﰲ زات ﻫﺬه اﻟﻐﺎ وأﻫﻤﻠﻨﺎ ﺗﻀﻤ ﻛﻞ اﻷﻛﺴﺠ ـــــ ا ﺤﺘﺠﺰ ﰲ ا ﻌـﺎدن ﻣﺜـﻞ اﻟﻜـﻮارﺗﺰ ) SiO2 ( ﻓﺴﻨﻘﻠﻞ ﻣﻦ ﺗﻘﺪﻳﺮ اﻟ ﻮﻓﺮة اﻹﺟﻤﺎﻟﻴﺔ ﺑﺸـﻜﻞ ". ﻛﺒ ﺗﺨﱪﻧﺎ ﺑﻠﻮرات اﻟﺴﻴﻠﻴﻜﺎ ﻋﻦ ﻣﺨﺰون ا ﻮاد ا ﺨﺘﻠﻔﺔ وﻛﻴﻒ ﺗﺠﺘﻤﻊ ﻟﻌﻤﻞ ﺑﻴﺌﺔ ﻫﺬا اﻟﻜﻮﻛﺐ ﻟﻜـ ﻣـﻦ ﻦ اﻟﺼـﻌﺐ ﺗﺤﺪﻳـ ﺪ ﻛﻤﻴـﺔ اﻟﻜﻮارﺗﺰ ا ﻮﺟﻮدة وﻣﺪى اﻧﺘﺸﺎر اﻟﻐﻴﻮم . ﻗﺎل ﺟﺮاﻧﺖ " : رﺑﻤﺎ ﺗﻜﻮن اﻟﻐﻴـﻮم ﻣﻮﺟـﻮدة ﻋﲆ ﻃﻮل اﻟﻔﺎﺻﻞ ﺑ اﻟﻨﻬـﺎر واﻟﻠﻴـﻞ وﻫـﻲ ا ﻨﻄﻘﺔ اﻟﺘﻲ ﺗﺴﺘﻜﺸﻔﻬﺎ ﻣﺮاﻗﺒﺎﺗﻨﺎ ." ﻧﻈـﺮاً ﻷن اﻟﻜﻮﻛﺐ ﺑ ﺎً ﻣﺪﻳ ﻣﺤﻜﻮم ﺠﺎﻧﺐ ﻧﻬﺎري ﺣ ﺎر ﺟﺪاً وﺟﺎﻧﺐ ﻟﻴﲇ أﻛﺜﺮ ﺑﺮودة ﻳﺤﺘﻤﻞ أن ﺗﺪور اﻟﻐﻴﻮم ﺣﻮل اﻟﻜﻮﻛﺐ وﻟﻜﻨﻬﺎ ﺗﺘﺒﺨـﺮ ﻋﻨـﺪﻣﺎ ﺗﺼﻞ إﱃ اﻟﺠﺎﻧـﺐ اﻟﻨﻬـﺎري اﻷﻛﺜـﺮ ﺣـﺮارة . ﻳﺤﺘﻤﻞ " أن ﺗﺤـﺮك اﻟﺮﻳـﺎح ﻫـﺬه اﻟﺠﺰﻳ ﺌـﺎت اﻟﺼﻐ ة ﺑﴪﻋﺔ آﻻف اﻷﻣﻴﺎل ﺑ ﺎﻟﺴﺎﻋﺔ ".