Free Astronomy Magazine November-December 2023 ARABIC VERSION

A Carbon-bearing molecules discovered in K2-18 b’s atmosphere by NASA/ESA/CSA Hannah Braun Bethany Downer new investigation with NASA’s James Webb Space Telescope into K2-18 b, an exoplanet 8.6 times as massive as Earth, has revealed the presence of carbon-bearing molecules including methane and carbon dioxide. Webb’s discovery adds to recent studies suggesting that K2-18 b could be a Hycean exoplanet, one which has the potential to possess a hydrogen-rich atmosphere and a water ocean-covered surface. The first insight into the atmospheric properties of this habitable-zone ex- oplanet came from observations with NASA’s Hubble Space Tele- scope, which prompted further studies that have since changed our understanding of the system. K2-18 b orbits the cool dwarf star K2-18 in the habitable zone and lies 120 light-years from Earth in the constellation Leo. Exoplanets such as K2-18 b, which have sizes be- tween those of Earth and Neptune, NOVEMBER-DECEMBER 2023 ﻣﺠﻠﺔ FreeAstronomy ﺎﻟﻌﺮ ﺔ 28 إ ﻛﺘﺸﺎف اﻟ ـ ﺠﺰ ﺌﺎت اﻟ ـ ﺤﺎﻣﻠﺔ ﻟﻠﻜﺮ ﻮنﻓﻲاﻟﻐﻼف ـاﻟ ﺠﻮيﻟـ K2-18 b : ﻘﻠﻢ ﻫﺎﻧﺎ ﺑﺮاونو ﺑ ﺜﺎﻧﻲداوﻧﺮ و ﺎﻟﺔ ﻧﺎﺳﺎ / و ﺎﻟﺔ اﻟﻔﻀﺎء اﻷوروﺑ ﺔ / و ﺎﻟﺔ اﻟﻔﻀﺎء اﻟﻜﻨﺪ ﺔ ﻳﻮﺿـــﺢﻫــــﺬا اﻟﺮﺳــــﻢاﻟﺘﺨ ﻠــــﻲاﻟﺸـــ ﻞ اﻟــــﺬ ــﺪ ﻗــﺪ ﻳ ــﮫ اﻟ ﻮﻛــﺐاﻟﻨ ﻤـﻲ وﻋﻠ K2-18 b ﻨﺎءً ﻋﻠﻰاﻟﺒ ﺎﻧﺎتاﻟﻌﻠﻤ ﺔ . ﻛﺘﺎﻟﻠﺒﺸﻒ ﺗﺤﻘﻴﻖ ﺟﺪﻳـﺪ أﺟـﺮاه ﺗﻠﺴـﻜﻮب ﺟﻴﻤﺲ وﻳﺐ اﻟﻔﻀﺎﺋﻲ ﻋـﻦ اﻟ ﻜﻮﻛـﺐ K2- 18 b وﻫﻮ ﻛﻮﻛﺐ ﻧﺠﻤـﻲ ﺒﻠـﻎ ﺗ ﻛﺘﻠﺘـﻪ 8.6 ﻣﺮة ﻛﺘﻠﺔ اﻷرض ﻋﻦ وﺟﻮد ﺟﺰﻳﺌﺎت ﺣﺎﻣﻠﺔ ﻟﻠﻜﺮﺑﻮن ﺑﻤﺎ ﰲ ذﻟﻚ ا ﻴﺜـﺎن وﺛـﺎﻧﻲ أﻛﺴـﻴﺪ اﻟﻜﺮﺑﻮن . ﻳﻀﻴﻒ اﻛﺘﺸﺎف ﺗﻠﺴﻜﻮب ﺟﻴﻤﺲ وﻳﺐ إﱃ اﻟﺪراﺳﺎت اﻟﺤﺪﻳﺜﺔ اﻟﺘﻲ ﺗﺸ أن إﱃ K2-18 b ﻳﻤﻜﻦ أن ﻳﻜـﻮن ﻛﻮﻛﺒـ ﺎً ﻧﺠﻤﻴـﺎً وﻫﻮ ﻛﻮﻛﺐ ﻟﺪﻳﻪ اﻟﻘﺪرة ﻋﲆ اﻣﺘﻼك ﻏـﻼف ﺟ ﻮي ﻏﻨﻲ ﺑﺎﻟﻬﻴـﺪروﺟ وﺳـﻄ ﺢ ﻣﻐﻄـﻰ ﺑﻤﺤـﻴﻂ . ﻣـﺎﺋﻲ ﺟـﺎءت أول ﻧﻈـﺮة ﺛﺎﻗﺒـﺔ ﻟﻠﺨﺼﺎﺋﺺ اﻟﺠﻮﻳﺔ ﻟﻬﺬا اﻟﻜﻮﻛـﺐ اﻟﻨﺠﻤـﻲ اﻟﺬي اﰲ ﻳﻮﺟﺪ ﻨﻄﻘﺔ اﻟ ﻟﻠﺤﻴﺎة ﺼﺎﻟﺤﺔ ﻣـﻦ ﻋﻤﻠﻴﺎت اﻟﺮﺻﺪ اﻟﺘﻲ أﺟﺮاﻫﺎ ﺗﻠﺴﻜﻮب ﻫﺎﺑﻞ اﻟﻔﻀﺎﺋﻲ اﻟﺘﺎﺑﻊ ﻟﻨﺎﺳﺎ، اﻷﻣﺮ اﻟﺬي دﻓـﻊ إﱃ إﺟﺮاء ا ﺰﻳﺪ ﻣﻦ اﻟﺪراﺳﺎت اﻟﺘﻲ ﻏ ت ﻓﻬﻤﻨﺎ ﻟﻠﻨﻈﺎم ﻣﻨﺬ ذﻟـﻚ اﻟﺤـ ، ر ﻳـﺪو K2-18 b ﺣﻮل اﻟﻨﺠﻢ اﻟﻘﺰم اﻟﺒﺎرد K2-18 ﰲ ا ﻨﻄﻘﺔ اﻟﺼﺎﻟﺤﺔ ﻟﻠﺤﻴﺎة وﻳﺒﻌﺪ 120 ﺳـﻨﺔ ﺿـﻮﺋﻴﺔ ﻣﻦ اﻷرض ﰲ ﻛﻮﻛﺒـﺔ اﻷﺳـﺪ إن . اﻟﻜﻮاﻛـﺐ اﻟﻨﺠﻤﻴ ـﺔ ﻣﺜ ـﻞ K2-18 b اﻟﺘ ـﻲ ﻳ ـﱰ اوح ﺣﺠﻤﻬﺎ ﺑ ﺣﺠﻢ اﻷرض وﻧﺒﺘﻮن ﻻ ﺗﺸـﺒﻪ أيﳾء ﰲ ﻧﻈﺎﻣﻨﺎ اﻟﺸﻤﴘ ﻛﺸﻒ ﻧﻮﻓﻤﺒﺮ - ﺩﻳﺴﻤﺒﺮ 2 0 2 3