Free Astronomy Magazine May-June 2023 ARABIC VERSION

from the brightness of the star and planet combined, they were able to successfully calculate how much in- frared light is being given off by the planet. Webb’s detection of a secondary eclipse is itself a major milestone. With the star more than 1,000 times brighter than the planet, the change in brightness is less than 0.1%. “There was also some fear that we’d miss the eclipse. The planets all tug on each other, so the orbits are not perfect,” said Taylor Bell, the post- doctoral researcher at the Bay Area Environmental Research Institute who analyzed the data. “But it was just amazing: The time of the eclipse that we saw in the data matched the predicted time within a couple of minutes.” The team analyzed data from five separate secondary eclipse observa- tions. “We compared the results to computer models showing what the temperature should be in different scenarios,” explained Ducrot. “The results are almost perfectly consis- tent with a blackbody made of bare rock and no atmosphere to circulate the heat. We also didn’t see any signs of light being absorbed by car- bon dioxide, which would be appar- ent in these measurements.” This research was conducted as part of Webb Guaranteed Time Observa- tion (GTO) program 1177, which is one of eight programs from Webb’s first year of science designed to help fully characterize the TRAPPIST-1 system. Additional secondary eclipse observations of TRAPPIST-1 b are currently in progress, and now that they know how good the data can be, the team hopes to eventually capture a full phase curve showing the change in brightness over the entire orbit. This will allow them to see how the temperature changes from the day to the nightside and confirm if the planet has an atmos- phere or not. “There was one target that I dreamed of having,” said Lagage, who worked on the development of the MIRI instrument for more than two decades. “And it was this one. This is the first time we can detect the emission from a rocky, temper- ate planet. It’s a really important step in the story of discovering exo- planets. ”     ﻣﻘﺎر ـــــﺔ درﺟـــــﺔ اﻟـــــ ﺤـ ﺮارة ﻓـــــﻲ اﻟـــــ ـ ﺠﺎﻧﺐ اﻷ ﻤـــــﻦ ﻣـــﻦ اﻟ ﻮﻛـــﺐ ﺗﺮاﺑ ﺴـــﺖ 1b ﻤـــﺎ ﺗـــﻢ ﻗ ﺎﺳـــﻬﺎ ﺎﺳــــــﺘﺨﺪام ـــــــﺎﻣ ا ﺗﻠﺴــــــ ﻮبﺟـــــــ ﻤﺲ ـــــــﺐ و اﻟﻔﻀﺎﺋﻲ ﻟﻸﺷﻌﺔ ﺗﺤﺖ اﻟــ ﻤﺮاء اﻟﻤﺘﻮﺳـﻄﺔ (MIRI) ﺗﻮﺿـﺢ درﺟـﺔ ﻟﻨﻤـﺎذج اﻟ ﻤﺒﻴـﻮﺗﺮاﻟـ ـ اﻟـــــــ ﺤﺮارة ﻓـــــــﻲﻇـــــــﻞ ﻇـــــــﺮوفﻣﺨﺘﻠﻔـــــــﺔ . ﺗﺄﺧـــــــﺬ ـــﺎراﻟـــ اﻟﻨﻤــﺎذج ﻓـــﻲ اﻻﻋﺘ ـ ﺨﺼﺎﺋﺺ اﻟﻤﻌﺮوﻓـــﺔ ﻟﻠﻨﻈـــــﺎم ﻤـــــﺎ ﻓـــــﻲذﻟـــــﻚد رﺟـــــﺔ ﺣـــــﺮارة اﻟـــــﻨ ﻢ واﻟﻤﺴﺎﻓﺔ اﻟﻤﺪار ﺔ ﻟﻠ ﻮﻛﺐ . ﻤﺎ ﺘﻢ ﻋـﺮض درﺟﺔ ﺣﺮارة اﻟـ ﺠﺎﻧﺐ اﻟﻨﻬـﺎري ﻟ ﻮﻛـﺐ ﻋ ﻄـﺎرد . ﻤﺮﺟﻊ [ NASA, ESA, CSA, Joseph Olmsted (STScI). Science: Thomas P. Greene (NASA Ames), Taylor Bell (BAERI), Elsa Ducrot (CEA), Pierre- Olivier Lagage (CEA)]. اﺳـﺘ ﺨﺪم اﻟﻔﺮﻳـﻖ ﺗﻘﻨﻴـﺔ ﺗﺴـﻤﻰ اﻟﻘﻴـﺎس اﻟﻀﻮﺋﻲ ﻟﻠﻜﺴﻮف اﻟﺜﺎﻧﻮي ﺣﻴﺚ ﻗﺎﻣﺖ ﻛﺎﻣ ا ) MIRI ( ﺑﻘﻴـﺎس اﻟﺘﻐ ـ ﰲ اﻟﺴـﻄﻮع ﻣــﻦ اﻟﻨﻈﺎم ﻣﻊ ﺗﺤﺮك اﻟﻜﻮﻛﺐ ﺧﻠﻒ اﻟـﻨﺠﻢ ﻋـﲆ اﻟﺮﻏﻢ ﻣﻦ أن اﻟﻜﻮﻛـﺐ ﺗﺮاﺑﻴﺴـﺖ - 1b ﻟـﻴﺲ ﺳﺎﺧﻨًﺎ ﺑﺪرﺟﺔ ﻛﺎﻓﻴﺔ ﻹﺻﺪار اﻟﻀـﻮء ا ﺮﺋـﻲ اﻟﺨﺎص ﺑﻪ ، إﻻ أﻧﻪ ﻳﺤﺘﻮي ﻋﲆ ﺗﻮﻫﺞ اﻷﺷﻌﺔ ﺗﺤﺖ ا ﻟﺤﻤﺮاء . ﺑﻄﺮح ﺳﻄﻮع اﻟﻨﺠﻢ ﻟﻮﺣﺪه ) أﺛﻨﺎء اﻟﻜﺴـﻮف اﻟﺜﺎﻧﻮي ( ﺗﻤﻜﻦ اﻟﻔﺮﻳﻖ ﻣـﻦ ﺣﺴـﺎب ﻣﻘـﺪار ﺿﻮء اﻷﺷﻌﺔ ﺗﺤﺖ اﻟﺤﻤﺮاء اﻟﺬي ﻳﻨﺒﻌﺚ ﻣـﻦ اﻟﻜﻮﻛﺐ ﺑﻨﺠﺎح ﺘـﱪ ﻳﻌ. اﻛﺘﺸـﺎف ﺗﻠﺴـﻜﻮب وﻳﺐ ﻟﻠﻜﺴﻮف اﻟﺜﺎﻧﻮي ﺑﺤﺪ ذاﺗﻪ أﻣﺮاً . ﻣﻬﻤـﺎً ﻧﻈﺮًا ﻷن اﻟﻨﺠﻢ أﻛﺜﺮ ﺳﻄﻮﻋًﺎ ﻣﻦ اﻟﻜﻮﻛﺐ ﺑـ ١٠٠٠ ﻣﺮة ﻳﻜﻮن اﻟﺘﻐﻴ ﰲ اﻟﺴﻄﻮع أﻗﻞ ﻣﻦ ٠.١٪. ﻛﺎن ﻫﻨﺎك أﻳﻀًﺎ ﺑﻌﺾ اﻟﺨﻮف ﻣـﻦ أن ﻳﻔﻮﺗﻨﺎ اﻟﻜﺴﻮف . ﻗﺎل ﺗﺎﻳﻠﻮر ﺑﻴﻞ اﻟﺒﺎﺣـﺚ ﰲ ﻣﺮﺣﻠـﺔ ﻣـﺎ ﺑﻌـﺪ اﻟ ــﺪﻛﺘﻮراه ﰲ ﻣﻌﻬ ــﺪ ﻟﻠﺒﺤــﻮث اﻟﺒﻴﺌﻴ ــﺔ ــــــــــ اﻟﺬي ﺣﻠﻞ اﻟﺒﻴﺎﻧﺎت و اﻟﺬي ﺣﻠﻞ اﻟﺒﻴﺎﻧﺎت " : ﻛﻞ اﻟﻜﻮاﻛـﺐ ﺗﺠـﺎذب ﺑﻌﻀﻬﺎ اﻟﺒﻌﺾ وﺑﺎﻟﺘﺎﱄ ﻓﺈن ا ﺪارات ﻟﻴﺴـﺖ ﻜﻦﻟ، ﻣﺜﺎﻟﻴﺔ ﻛﺎن ﻣﺬﻫﻼً أن وﻗـﺖ اﻟﻜﺴـﻮف اﻟ ـﺬي وﺟ ـﺪﻧﺎه ﰲ اﻟﺒﻴﺎﻧ ـﺎت ﺎً ﻄﺎﺑﻘــ ﻣ ﺟ ـﺎء ﻟ ﻠﻤﺘﻮﻗﻊ ﰲ ﻏﻀﻮن دﻗﻴﻘﺘ . ﺣﻠﻞ اﻟﻔﺮﻳﻖ اﻟﺒﻴﺎﻧـﺎت ﻣـﻦ ﺧﻤـﺲ ﻋﻤﻠﻴـﺎت رﺻـﺪ ﺛﺎﻧﻮﻳـﺔ ﻣﻨﻔﺼـﻠﺔ ﻟﻠﻜﺴـﻮف . أوﺿـﺢ Ducrot " : ﻟﻘــﺪ ﻗﺎرﻧــﺎ اﻟﻨﺘــﺎﺋﺞ ﺑﻨﻤــﺎذج اﻟﻜﻤﺒﻴﻮﺗﺮ اﻟﺘﻲ ﺗﻮﺿﺢ درﺟﺔ اﻟﺤـﺮارة اﻟﺘـﻲ ﻳﺠﺐ أن ﺗﻜﻮن ﰲ ﺳـﻴﻨﺎرﻳﻮﻫﺎت ﻣﺨﺘﻠ ". ﻔـﺔ " اﻟﻨﺘﺎﺋﺞ ﻣﺘﻮاﻓﻘﺔ ﺗﻤﺎﻣًﺎ ﺗﻘﺮﻳﺒًـﺎ ﻣـﻊ ﺟﺴـﻢ أﺳﻮد ﻳﺘﻜﻮن ﻣﻦ اﻟﺼﺨﻮر اﻟﻌﺎرﻳﺔ وﻻ ﻳﻮﺟـﺪ ﻏﻼف ﺟﻮي ﻟﺘﻮزﻳﻊ اﻟﺤﺮارة . ﻛﻤﺎ أﻧﻨﺎ ﻟـﻢ ﻧـﺮ أي ﻋﻼﻣــﺎت ﻋــﲆ اﻣﺘﺼـﺎص ﺛــﺎﻧﻲ أﻛﺴـﻴﺪ اﻟﻜﺮﺑﻮن ﻟﻠﻀﻮء وﻫﻮ ﻣﺎ ﺳﻴﻜﻮن واﺿـﺤًﺎ ﰲ ﻫﺬه اﻟﻘﻴﺎﺳﺎت ." ﺗﻢ إﺟﺮاء ﻫﺬا اﻟﺒﺤﺚ ﻛﺠﺰء ﻣﻦ ﺑﺮﻧﺎﻣﺞ (GTO) 1177 واﻟ ﺬي ﻳﻌﺪ واﺣـﺪًا ﻣﻦ ﺛﻤﺎﻧﻴﺔ ﺑﺮاﻣﺞ ﻣﻦ اﻟﺴﻨﺔ اﻷوﱃ ﻣﻦ اﻟﻌﻠﻮم ﻟﺘﻠﺴــﻜﻮب وﻳــﺐ ﻣﺼــﻤﻤﺔ ﻟﻠﻤﺴــﺎﻋﺪة ﰲ ـــــــ ﺗﻮﺻﻴﻒ ﻧﻈﺎم اﻟﻨﺠﻢ ﺗﺮاﺑﻴﺴـﺖ - 1 ﺑﺸـﻜﻞ . ﻛﺎﻣﻞ ﺗﺠﺮي ﺣﺎﻟﻴًﺎ ﻋﻤﻠﻴﺎت ﻣﺮاﻗﺒﺔ إﺿﺎﻓﻴﺔ ﻟﻠﻜﺴﻮف اﻟﺜﺎﻧﻮي ﻟﻠﻜﻮﻛﺐ ﺗﺮاﺑﻴﺴـﺖ – 1b واﻵن ﺑﻌﺪ أن ﻋﺮﻓﻮا ﻣﺪى دﻗﺔ اﻟﺒﻴﺎﻧﺎت ﻳﺄﻣﻞ اﻟﻔﺮﻳﻖ ا ﻟﺘﻘ ﺎط ﻣﻨﺤﻨﻰ ﻃﻮر ﻛﺎﻣـﻞ ﻳُﻈﻬـﺮ اﻟﺘﻐ ﰲ اﻟﺴﻄﻮع ﻋﲆ ﻣﺪى ا ﺪار ﺑﺄﻛﻤﻠـﻪ . ﺳﻴﺴﻤﺢ ذﻟﻚ ﺑﻤﻌﺮﻓﺔ ﻛﻴـﻒ ﺗﺘﻐـ درﺟـﺔ اﻟﺤﺮارة ﻣﻦ اﻟﻨﻬﺎر إﱃ اﻟﻠﻴﻞ وﺗﺄﻛﻴـﺪ إذا ﻣـﺎ ﻛﺎن ﻟﻠﻜﻮﻛﺐ ﻏﻼف ﺟﻮي أم ﻻ . - ﻣﺎﻳﻮ ﻳﻮﻧﻴﻮ 2023