Free Astronomy Magazine July-August 2025 ARABIC VERSION

transmission spectrum captured by NASA’s James Webb Space Telescope reveals the presence of water (H 2 O) and the possible presence of sulfur dioxide(SO 2 )andcarbonmonoxide(CO),butnosignsofcarbondioxide(CO 2 )ormethane(CH 4 ),intheatmosphereofthehotsub-Neptuneexo- planetTOI-421b.Theobservationssupportthehypothesisthatplanetsthishot(TOI-421bisabout1,340°F)haveclearatmospheresthatarenotob- scured by clouds and haze. The spectrum was made by measuring the decrease in apparent brightness of different wavelengths (colors) of starlight as theplanettransited,ormovedacrossthefaceofthestar.Duringatransit,somewavelengthsofstarlightaretransmittedthroughtheplanet’satmos- phere, while others are partially blocked. Because each molecule absorbs a unique combination of wavelengths, the transmission spectrum can beused to identify gases in the atmosphere. This spectrum was made by combining data captured in 2023 by Webb’s NIRISS (Near-Infrared Imager and Slitless Spectrograph) and NIRSpec (Near-Infrared Spectrograph). [NASA, ESA, CSA, Joseph Olmsted (STScI)] Withouthazeorclouds,researchers expectedtoseeaclearatmosphere – and they did! “We saw spectral featuresthatweattributetovarious gases,andthatallowedustodeter- minethecompositionoftheatmos- phere,” said the University of Maryland’sBrianDavenport,athird- year Ph.D. student who conducted the primary data analysis. “Whereas with many of the other sub-Nep- tunesthathadbeenpreviouslyob- served,weknowtheiratmospheres aremadeofsomething,butthey’re being blocked by haze.” The team found water vapor in the planet’s atmosphere, as well as ten- tative signatures of carbon monox- ide and sulfur dioxide. Then there are molecules they didn’t detect, such as methane and carbon diox- ide. From the data, they can also infer that a large amount of hydro- gen is in TOI-421 b’s atmosphere. Thelightweighthydrogenatmos-    ﻜﺸﻒ ﻋﺒﻮر ﻃ ﻒ اﻟﺘﻘﻄﮫ ﺗﻠﺴ ﻮبﺟ ﻤﺲو ﺐ اﻟﻔﻀﺎﺋﻲ اﻟﺘﺎﺑﻊ ﻟﻮ ﺎﻟﺔ ﻧﺎ ﺳـﺎ ﻋـﻦ وﺟـﻮد اﻟﻤـﺎء ) H2O ( ـﺖ واﺣﺘﻤـﺎل وﺟـﻮد ﺛـﺎﻧﻲ أﻛﺴـ ﺪ اﻟﻜ ) SO2 ( وأول أﻛﺴـ ﺪ اﻟﻜﺮـﻮن )CO ( وﻟﻜـﻦ ﻻ ﺗﻮﺟـﺪ أيﻋﻼﻣــﺎت ﻋﻠــﻰوﺟــﻮد ﺛـﺎﻧﻲ أﻛﺴــ ﺪ اﻟﻜﺮــﻮن ) CO2 ( أو اﻟﻤ ﺜــﺎن ) CH4 ( ﻓــﻲ اﻟﻐــﻼف اﻟــ ـ ﺠﻮي ﻟﻠ ﻮﻛــﺐ اﻟ ﻨ ﻤــﻲ TOI-421b اﻟﺴـﺎﺧﻦ ﺗﺤــﺖ ﻧﻴ ﺘــﻮﻧﻲ . ﺗــﺪﻋﻢ اﻷرﺻــﺎد ــﺄن اﻟ ﻮ اﻟﻔﺮﺿــ ﺔ اﻟﻘﺎﺋﻠــﺔ اﻛــﺐ اﻟﺴﺎﺧﻨﺔ ) ﻣﺜﻞ TOI-421b ( اﻟ ﺗ ﻠﻎ درﺟﺔ ﺣﺮارﻬﺎ ﺣﻮاﻟﻲ 1340 درﺟﺔ ﻓﻬﺮﻬﺎ ﺖ ) 726 درﺟﺔ ﻣﺌﻮ ﺔ ( ﺗﺘﻤﺘﻊ ﺄﺟﻮاء ﺻﺎﻓ ﺔ ﻏ ﻣﻐﻄﺎة ﺎﻟﻐﻴﻮم واﻟﻀ ﺎ ـﺔ اﻟﻐـﻼف اﻟــﺠﻮي ﻤﻤﺎ ﺴﻤﺢ ﺑﺮﺻﺪ ﺗﺮﻛﻴ . ﺪﻗﺔ ـﺔ ﻣﺨﺘﻠﻔـﺔ ﺗﻢ إﻧﺸﺎء اﻟﻄ ﻒ ﻘ ﺎس اﻻﻧﺨﻔـﺎضﻓـﻲ اﻟﺴـﻄﻮع اﻟﻈـﺎﻫﺮيﻷﻃـﻮال ﻣﻮﺟ أﻟـﻮان ) ﻟﻀـﻮ ( ء اﻟﻨﺠـﻮم أﺛﻨـﺎء ﻣـﺮور اﻟ ﻮﻛـﺐ أﻣﺎﻣـﮫ . أﺛﻨـﺎء اﻟﻌﺒـﻮرﺗﻨﺘﻘـﻞ ﻌـﺾ أﻃـﻮال اﻟﻤﻮﺟـﺎت ﻣـﻦ ﺿـﻮء اﻟﻨﺠﻮم ﻋ اﻟﻐﻼف اﻟ ـ ﺠﻮي ﻟﻠ ﻮﻛﺐ ﺑ ﻨﻤﺎ ﺗ ﺤﺠﺐ أﻃﻮال ﻣﻮﺟ ﺔ أﺧﺮىﺟﺰ ﺎ . ﻷن ﻞ ﺟﺰيء ﻤﺘﺺﻣﺰ ﺠﺎً ﻓﺮ ﺪاً ﻣﻦ اﻷﻃﻮال اﻟﻤﻮﺟ ﺔ ﻤﻜﻦ اﺳﺘﺨﺪامﻃ ﻒ ﻋﺒﻮر اﻟ ﻮﻛﺐ ﻟﺘﺤﺪ ﺪ اﻟﻐﺎزات ﻓـﻲﻏﻼﻓـ ﮫ ـ اﻟــ . ﺠﻮي ــﺪﻣﺞ اﻟﺒ ﺎﻧــﺎت اﻟﻤﻠﺘﻘﻄــﺔ ﻋــﺎم ــﻒ أُﻧــﺘﺞ ﻫــﺬا اﻟﻄ 2023 ﺑﻮاﺳــﻄﺔ ﺟﻬــﺎزي NIRISS ) ﻣﺼــﻮراﻷﺷــﻌﺔ ﺗﺤــﺖ اﻟــ ـ ــﺪونﺷــﻘﻮق ـﺎف ــﺔ وﻣﻄ ﻤﺮاء اﻟﻘﺮ ﻟ( ــﺐ ﺘﻠﺴــ ﻮب و و NIRSpec ) ــﺎف ﻣﻄ اﻷﺷﻌﺔ ﺗﺤﺖ اﻟ ـ ﻤﺮاء اﻟﻘﺮ ﺔ ( دﻗﺔ اﻟﻘ ﺎسوﺗﺴﺎﻋﺪ ﻫﺬﻩ اﻟﺒ ﺎﻧﺎت ﻓﻲﻓﻬﻢ ﻣﻊ اﺳﺘﺨﺪام ﺗﻘﻨ ﺎت ﻣﻌﺎﻟـﺠﺔ ﻣﺘﻘﺪﻣﺔ ﻟﺘﺤﺴ اﺟﻮاء اﻟ ﻮﻛﺐ اﻟﻨ ﻤ ﺔ . [NASA, ESA, CSA, Joseph Olmsted (STScI)] ﺑﺪون ﺿﺒﺎب أو ﻏﻴﻮم ﺗﻮ ﻗﻊ اﻟﺒﺎﺣﺜﻮن رؤﻳـﺔ ﻏﻼف ﺟﻮي ﺻﺎﰲ وﻗﺪ ﻓﻌﻠﻮا ! ﻗﺎل ﺑﺮاﻳﺎن داﻓﻨﺒـﻮرت ﻃﺎﻟـﺐ اﻟـﺪﻛﺘﻮراه ﰲ اﻟﺴﻨﺔ اﻟﺜﺎﻟﺜﺔ ﺑﺠﺎﻣﻌﺔ ﻣﺎرﻳﻼﻧﺪ واﻟﺬي أﺟـﺮى اﻟﺘﺤﻠﻴﻞ اﻷﺳﺎﳼ ﻟﻠ ﺒﻴﺎﻧﺎت " : ﻟﻘﺪ رأﻳﻨﺎ ﺳﻤﺎت ﻌﺰى ﻃﻴﻔﻴﺔ ﺗ إﱃ ﻏﺎزات ﻣﺨﺘﻠﻔﺔ وﺳﻤﺤﺖ ﻟﻨﺎ ﺑﺘﺤﺪﻳﺪ ﺗﺮﻛﻴﺐ اﻟﻐﻼف اﻟﺠﻮي ." أﺿﺎف " : ﺑﻴﻨﻤﺎ ﰲ اﻟﻌﺪﻳﺪ ﻣﻦ أﻃﻴﺎف اﻟﻜﻮاﻛﺐ ﺗﺤﺖ ﻧﺒﺘﻮﻧﻴﺔ اﻷﺧﺮى اﻟﺘـﻲ رﺻـﺪت ﺳـﺎﺑﻘ ﺎً ﻧﻌﻠﻢ أن أﻏﻠﻔﺘﻬﺎ اﻟﺠﻮﻳﺔ ﺗﺘﻜﻮن ﻣﻦ ﳾء ﻣـﺎ ﻟﻜﻦ اﻟﻀﺒﺎب ﻳﺤﺠﺒﻬﺎ . وﺟﺪ اﻟﻔﺮﻳﻖ ﺑﺨﺎر ﻣﺎء ﰲ اﻟﻐ ـﻼف اﻟﺠ ـﻮي ﻟﻠﻜﻮﻛ ـﺐ ﺑﺎﻹﺿ ـﺎﻓﺔ إﱃ ﺑﺼﻤﺎت أول أﻛﺴﻴﺪ اﻟﻜﺮﺑﻮن وﺛـﺎﻧﻲ أﻛﺴـﻴﺪ اﻟﻜﱪ . ﻳﺖ ﺛﻢ ﻫﻨﺎك ﺟﺰﻳﺌـﺎت ﻟـﻢ ﻳﻜﺘﺸـﻔﻮﻫﺎ ﻣﺜﻞ ا ﻴﺜـﺎن وﺛـﺎﻧﻲ أﻛﺴـﻴﺪ اﻟﻜﺮﺑـﻮن وﻣـﻦ اﻟﺒﻴﺎﻧﺎت ﻳﻤﻜﻨﻬﻢ أﻳﻀ ﺎً اﺳﺘﻨﺘﺎج وﺟﻮد ﻛﻤﻴـﺔ ﻛﺒ ة ﻣـﻦ اﻟﻬﻴـﺪروﺟ ﰲ اﻟﻐـﻼف اﻟﺠـﻮي ﻠﻟ ﻜﻮﻛـﺐ TOI-421 b . إن ﻃﺒﻴﻌـﺔ اﻟﻐـﻼف اﻟﺠﻮي اﻟﻬﻴﺪروﺟﻴﻨﻲ ﺧﻔﻴﻒ اﻟﻮزن ﻣﻔﺎﺟـﺄة ﻛﺒ ة ﻟﻠﺒﺎﺣﺜ . ﻗﺎل ﻛﻴﻤﺒﺘﻮن " : ﻟﻘﺪ اﻗﺘﻨﻌﻨـﺎ اً ﻣـﺆﺧﺮ ﺑـﺄن ﺗﻠـﻚ اﻟﻜﻮاﻛـ ﺐ ﺗﺤـﺖ ﻧﺒﺘﻮﻧﻴـﺔ ﺎﻟﻘﻠﻴﻠﺔ ـ اﻟﺘﻲ رﺻﺪﻫﺎ وﻳﺐ ﻛﺎﻧﺖ ﺗﺤﺘﻮي ﻋﲆ أﻏﻠﻔﺔ ﻣﻦ اﻟﺠﺰﻳﺌﺎت اﻟﺜﻘﻴﻠﺔ، ﻟﺬﻟﻚ أﺻﺒﺢ ﻫﺬا اﻟﻘﻠﻴﻠﺔ اﻟﺘﻲ رﺻﺪﻫﺎ وﻳﺐ ﻛﺎﻧﺖ ﺗﺤﺘﻮ ي ﻋـﲆ أﻏﻠﻔﺔ ﻣﻦ اﻟﺠﺰﻳﺌﺎت اﻟﺜﻘﻴﻠﺔ ﻟﺬﻟﻚ أﺻﺒﺢ ﻫـﺬا ﺗﻮﻗﻌﻨﺎ ﺛﻢ وﺟﺪﻧﺎ ﻋﻜ ". ﺲ ذﻟﻚ ﻳﺸ ﻫـﺬا إﱃ أن اﻟﻜﻮﻛﺐ TOI-421 b ﻳ رﺑﻤﺎ ﻜﻮن ﻗﺪ ﺗﺸﻜﻞ وﺗﻄﻮر ﺑﺸﻜﻞ ﻣﺨﺘﻠﻒ ﻋـﻦ اﻟﻜﻮاﻛـﺐ ﺗﺤـﺖ ﻧﺒﺘﻮﻧﻴﺔ اﻷﻛﺜﺮ ﺑﺮودة اﻟﺘﻲ رﺻﺪت ﺳﺎﺑﻘ . ﺎً ﻳ ﻌـﺪ اﻟﻐـﻼف اﻟﺠـﻮي اﻟـﺬي ﻳﻬـﻴﻤﻦ ﻋﻠﻴ ـﻪ ا ﻟﻬﻴﺪروﺟ ﻣﺜ اً ﻟﻼﻫﺘﻤﺎم أﻳﻀ ﺎً ﻷﻧﻪ ﻳﺤﺎﻛﻲ ﺗﻜﻮﻳﻦ اﻟﻨﺠﻢ ا ﻀﻴﻒ ﻟﻠﻜﻮﻛﺐ TOI-421 b . إذا أﺧـﺬﻧﺎ ﻧﻔـﺲ اﻟﻐـﺎز اﻟـﺬي ﻛـﻮن اﻟـﻨﺠﻢ ا ﻀـﻴﻒ ووﺿـﻌﻨﺎه ﻓـﻮق اﻟﻐـﻼف اﻟﺠـﻮي ﻟﻜﻮﻛﺐ ووﺿﻌﻨﺎه ﻋﻨـﺪ درﺟـﺔ ﺣـﺮارة أﺑـﺮد ﺑﻜﺜ ـ ﻣ ـﻦ درﺟـﺔ ﺣـﺮارة ﻫـﺬا اﻟﻜﻮﻛ ـﺐ ﻓﺴﺘﺤﺼﻞ ﻋﲆ ﻧﻔﺲ ﺗﺮﻛﻴﺒﺔ اﻟﻐﺎزات . ﻗﺎل ﻛﻴﻤﺒﺘﻮن :" ﻫﺬه اﻟﻌﻤﻠﻴﺔ أﻛﺜﺮ اﻧﺴـﺠﺎﻣ ﺎً ﻣﻊ اﻟ ﻜﻮاﻛﺐ اﻟﻌﻤﻼﻗﺔ ﰲ ﻧﻈﺎﻣﻨـﺎ اﻟﺸﻤـ ﴘـ وﺗﺨﺘﻠﻒ ﻋﻦ اﻟﻜﻮاﻛﺐ ﺗﺤﺖ ﻧ ﺒﺘﻮﻧﻴﺔ اﻷﺧـﺮى اﻟﺘﻲ رُﺻ ﺪت ﺑﺎﺳﺘﺨﺪام ﺗﻠﺴﻜﻮب وﻳﺐ ﺣﺘـﻰ اﻵن ﻛﻤﺎ أﻧﻪ إﱃ ﺟﺎﻧﺐ ﻛﻮﻧﻪ أﻛﺜﺮ ﺣﺮارة ﻣـﻦ اﻟﻜﻮاﻛﺐ ﺗﺤﺖ ﻧﺒﺘﻮﻧﻴﺔ اﻷﺧﺮى اﻟﺘﻲ رﺻـﺪت ﺎً ﺳـﺎﺑﻘ ﺑﺎﺳـﺘﺨ ﺪام ﺗﻠﺴـﻜﻮب وﻳ ـﺐ ﻳ ـﺪور اﻟﻜﻮﻛــﺐ TOI-421b ﺣــﻮل ﻧﺠــﻢ ﻳﺸــﺒﻪ اﻟﺸﻤﺲ . ﺗﺪور ﻣﻌﻈﻢ اﻟﻜﻮاﻛﺐ ﺗﺤﺖ ﻧﺒﺘﻮﻧﻴﺔ اﻷﺧﺮى اﻟﺘﻲ ر ﺻﺪت ﺣﺘﻰ اﻵن ﺣـﻮل ﻧﺠـﻮم أ ﺻﻐﺮ وأﺑﺮد ﺗ ﺴﻤﻰ اﻷﻗﺰام اﻟﺤﻤﺮاء . ﻤﺜﻞ ﻫﻞ ﻳ اﻟﻜﻮﻛﺐ TOI-421b رﻣﺰ ا ﻟﻠﻜﻮاﻛﺐ ﺗﺤﺖ ﻧﺒﺘﻮﻧﻴﺔ ﺳﺎﺧﻨ ﺔ ﺗﺪور ﺣﻮل ﻧﺠﻮم ﺗﺸﺒﻪ اﻟﺸـﻤﺲ أم أن اﻟﻜﻮاﻛـﺐ اﻟ ﻨﺠﻤﻴـﺔ ﺷــﺪﻳﺪة اﻟﺘﻨﻮع؟ ﻌﺮﻓﺔ ذﻟﻚ ﻳﺮﻏﺐ اﻟﺒﺎﺣﺜﻮن ﰲ رﺻـﺪ ا ﺰﻳﺪ ﻣﻦ اﻟﻜﻮاﻛـﺐ ﺗﺤـﺖ ﻧﺒﺘﻮﻧﻴـﺔ ﺳـﺎﺧﻨﺔ ﻟﺘﺤﺪﻳﺪ ﻣـﺎ إ ذا ﻛﺎﻧـﺖ ﻫـﺬه ﺣﺎﻟـﺔ ﻓﺮﻳـﺪة أم اﺗﺠﺎﻫ ﺎً أوﺳﻊ . ﻳﺄﻣﻞ اﻟﻌﻠﻤﺎء ﰲ اﻛﺘﺴﺎب رؤى ﺣـﻮل ﺗﻜـﻮﻳﻦ اﻷﻧﻈﻤﺔ اﻟﻜﻮﻛﺒﻴـﺔ وﺗﻄـﻮر ﻫـﺬه اﻟﻜﻮاﻛـﺐ ا ﻟﻨﺠﻤﻴﺔ اﻟﺸﺎﺋﻌﺔ . ﻗﺎل داﻓﻨﺒﻮرت " : ﻟﻘﺪ اﻛﺘﺸﻔﻨﺎ ﻃﺮﻳ ﻘﺔ ﺟﺪﻳﺪة ﻟﺪراﺳﺔ ﻫﺬه اﻟﻜﻮاﻛﺐ ﺗﺤﺖ ﻧﺒﺘﻮﻧﻴـﺔ واﻟﺘـﻲ ﺗﺘﻤﻴــﺰ ﺑــﺪرﺟﺎت ﺣــﺮارة ﻋﺎﻟﻴــﺔ ﻗﺎﺑﻠــﺔ ﻟﻠﺘﺸﺨﻴﺺ . ﻟﺬا رﺑﻤﺎ ﻧﻜﻮن أﻛﺜـﺮ ﻗـﺪرة ﻋـﲆ اﻟﺘﻌﺮف ﻋﲆ ﻫﺬه اﻟﻜﻮاﻛﺐ اﻟﻨﺠﻤﻴﺔ اﻟﻔﺮﻳـﺪة وﻓﻬﻢ ﻃﺒﻴﻌﺘﻬﺎ ﺑﺸﻜﻞ أ ﻋﻤﻖ ﰲ ا ﺴﺘﻘﺒﻞ ﻣﻤﺎ ﻳﻔﺘﺢ آﻓﺎﻗﺎ ﺟﺪﻳﺪة ﻟﻠﺒﺤﺚ ". ﻳﻮﻟﻴﻮ - ﺃﻏﺴﻄﺲ 2 0 2 5