Free Astronomy Magazine July-August 2024 ARABIC VERSION

R 54 Webb hints at possible atmosphere surrounding 55Cancri e by NASA/ESA/CSA Margaret W. Carruthers & Christine Pulliam esearchers using NASA’s James Webb Space Telescope may have detected atmospheric gases surrounding 55 Cancri e, a hot rocky exoplanet 41 light-years from Earth. This is the best evidence to date for the existence of any rocky planet atmosphere outside our solar system. Renyu Hu from NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California, is lead author on a paper published in Nature . “Webb is pushing the frontiers of exoplanet characterization to rocky planets,” Hu said. “It is truly en- abling a new type of science.” 55 Cancri e, also known as Janssen, is one of five known planets orbiting the Sun-like star 55 Cancri, in the constellation Cancer. With a diame- ter nearly twice that of Earth and density slightly greater, the planet is classified as a super-Earth: larger than Earth, smaller than Neptune, and likely similar in composition to the rocky planets in our solar system. To describe 55 Cancri e as “rocky,” however, could leave the wrong im- pression. The planet orbits so close to its star (about 1.4 million miles, or one-twenty-fifth the distance be- tween Mercury and the Sun) that its surface is likely to be molten – a bubbling ocean of magma. With such a tight orbit, the planet is also likely to be tidally locked, with a dayside that faces the star at all times and a nightside in perpetual darkness. In spite of numerous ob- servations since it was discovered to transit in 2011, the question of whether or not 55 Cancri e has an atmosphere – or even could have one given its high temperature and the continuous onslaught of stellar radiation and wind from its star – has gone unanswered. “I’ve worked on this planet for more than a decade,” said Diana Dragomir, an exoplanet researcher at the Univer- sity of New Mexico and co-author on the study. “It’s been really frustrat- JULY-AUGUST 2024 ﻣﺠﻠﺔ FreeAstronomy ﺎﻟﻌﺮ ﺔ " و ﺐ" ﻳﺮﺻﺪ ﻏﻼﻓ ﺎً ﺟﻮ ﺎً ﻣﺤﺘﻤﻼً ﻳﺤ ﻂ ﺑـ 55 ﺎﻧﻜﺮيإي : ﻘﻠﻢ ﺑﻮﻟ ﺎم ﻣﺎرﻏﺮﺖ ﺎروﺛﺮزوﻛﺮﺴﺘ و ﺎﻟﺔ ﻧﺎﺳﺎ / و ﺎﻟﺔ اﻟﻔﻀﺎء اﻷوروﺑ ﺔ / و ﺎﻟﺔ اﻟﻔﻀﺎء اﻟﻜﻨﺪ ﺔ اﻛﺘﺸـﻒ اﻟﺒ ـﺎﺣﺜﻮن اﻟ ـﺬﻳﻦ ﻳﺴ ـﺘﺨﺪﻣﻮن ﺗﻠﺴﻜﻮب ﺟـﻴﻤﺲ وﻳـﺐ اﻟﻔﻀـﺎﺋﻲ اﻟﺘـﺎﺑﻊ ﻟ ﻮﻛﺎﻟـﺔ ﻧﺎﺳـﺎ ﻏـﻼف ﺟـﻮي ﻣﺤﺘﻤـﻞ ﻣـﻦ اﻟﻐﺎزات )ﺑـ ﻳﺤﻴﻂ 55 ﻛـﺎﻧﻜﺮي إي ( وﻫـﻮ ﻛﻮﻛ ـﺐ ﺻ ـﺨﺮي ﺳ ـﺎﺧﻦ ﻳﻮﺟ ـﺪ ﺧ ـﺎرج ا ﺠﻤﻮﻋﺔ اﻟﺸﻤﺴﻴﺔ ﻋﲆ ﻣﺴـﺎﻓﺔ 41 ﺳـﻨﺔ ﺿﻮﺋﻴﺔ ﻣﻦ اﻷرض وﻫﺬا أﻓﻀﻞ دﻟﻴﻞ ﺣﺘـﻰ اﻵن ﻋﲆ وﺟﻮد أي ﻏﻼف ﺟﻮي ﻷي ﻛﻮﻛـﺐ ﺻﺨﺮي ﺧﺎرج ﻧﻈﺎﻣﻨﺎ اﻟﺸﻤ . ﴘـ ) رﻳﻨﻴﻮ ﻫﻮ ( ﻣﻦ ﻣﺨﺘﱪ اﻟﺪﻓﻊ اﻟﻨﻔﺎث اﻟﺘﺎﺑﻊ ﻟ ﻮﻛﺎﻟﺔ ﻧﺎﺳﺎ ﰲ ﺑﺎﺳﺎدﻳﻨﺎ ﻛﺎﻟﻴﻔﻮرﻧﻴـﺎ ﻫـﻮ و ا ﺆﻟﻒ اﻟﺮﺋﻴ ـ ﴘ ﻟﻮرﻗﺔ ﺑﺤﺜﻴـﺔ ﻣﻨﺸـﻮرة ﰲ . ﻧﻴﺘﴩ ﻣﺠﻠﺔ : "(ﻫﻮ) ﻗﺎل إن وﻳﺐ ﻳﺪﻓﻊ ﺣﺪود ﺗﻮﺻـﻴﻒ اﻟﻜﻮاﻛﺐ اﻟﻨﺠﻤﻴﺔ إﱃ اﻟﻜﻮاﻛﺐ اﻟ ﻣﺎ ﺔ ﺼﺨﺮﻳ ﻳ ﻤﻜﻦ ﻣﻦ ﻇﻬﻮر ﻧﻮع ﺟﺪﻳﺪ ﻣﻦ اﻟﻌﻠﻮم ". )55 ﻛـﺎﻧﻜﺮي إي ( ا ﻌـﺮوف أﻳﻀًـﺎ ﺑﺎﺳـﻢ (ﻦ ﻳﺎﻧﺴ) ﻫـﻮ واﺣـﺪ ﻣـﻦ ﺧﻤﺴـﺔ ﻛﻮاﻛـﺐ ﻣﻌﺮوﻓﺔ ﺗﺪور ﺣﻮل اﻟﻨﺠﻢ اﻟﺸﺒﻴﻪ ﺑﺎﻟﺸﻤﺲ )55 ﻛﺎﻧﻜﺮي إي ( ﰲ ﻛﻮﻛﺒﺔ اﻟﴪﻃﺎن ﻘﻄﺮ ﺑ ﻳﻘﺎرب ﺿﻌ ﻒ ﻗﻄﺮ اﻷرض وﻛﺜﺎﻓﺘـﻪ أﻛـﱪ ﻗﻠﻴﻼً ﻳُﺼﻨﻒ اﻟﻜﻮﻛﺐ ﻋﲆ أﻧﻪ أرض : ﻋﻤﻼﻗﺔ أ ﻛﱪ ﻣﻦ اﻷرض وأﺻﻐﺮ ﻣـﻦ ﻧﺒﺘـﻮن وﻣـﻦ ا ﺤﺘﻤــﻞ أن ﻳﻜــﻮن ﻣﺸــﺎﺑﻬ ﺎً ﰲ ﺗﻜﻮﻳﻨــﻪ ﻟﻠﻜﻮاﻛﺐ اﻟﺼﺨﺮﻳﺔ ﰲ ﻧﻈﺎﻣﻨﺎ اﻟﺸﻤﴘ . وﻣﻊ ذﻟﻚ ﻓﺈن وﺻﻒ 55) ﻛﺎﻧﻜﺮي إي ( ﺑﺄﻧﻪ « ﺨﺮيﺻ» ﻳﻤﻜﻦ أن ﻳﱰك اﻧﻄﺒﺎﻋـﺎ ﺧﺎﻃﺌـﺎً ﻳﺪور اﻟﻜﻮﻛﺐ ﺑﺎﻟﻘﺮب ﻣﻦ ﻧﺠﻤﻪ ﺣﻮاﱄ ) 1.4 ﻣﻠﻴﻮن ﻣﻴﻞ أو 20/25 ا ﺴﺎﻓﺔ ﺑ ﻋﻄـﺎرد واﻟﺸ ـﻤﺲ ﺮﺟﺢ وﻳ ـ ( أن ﻳﻜ ـﻮن ﺳــﻄﺤﻪ - ﻣﻨﺼﻬﺮاً ﻣﺤﻴﻄﺎً ﻓﻘﺎﻋﻴـﺎً ﻣـﻦ اﻟﺼـﻬﺎر ة و ﻣﻊ ﻣﺜﻞ ﻫﺬا ا ﺪار اﻟﻀﻴﻖ ﻣﻦ ا ﺤﺘﻤـﻞ أن ﻳﻜﻮن اﻟﻜﻮﻛﺐ ﻣﻘﻔﻞ ﻣـﺪﻳﺎً ﺣﻴـﺚ ﻳﻮاﺟـﻪ ﺟﺎﻧـﺐ اﻟﻨﻬـﺎر اﻟـﻨﺠﻢ ﰲ ﺟﻤﻴـﻊ اﻷوﻗـﺎت وﺟﺎﻧﺒﻪ اﻟﻠﻴﲇ ﰲ ﻇﻼم داﺋﻢ . ﻋﲆ اﻟﺮﻏﻢ ﻣـﻦ اﻷرﺻﺎد اﻟﻌﺪﻳﺪة ﻣﻨﺬ اﻛﺘﺸﺎف ﻋﺒﻮره ﰲ ﻋﺎم 2011 ﻓﺈن اﻟﺴﺆال ا ﻄﺮوح ﻣﺎ إذا ﻛﺎن ﻟﺪى 55) ﻛﺎﻧﻜﺮي إي ( ﻏﻼف ﺟﻮي أم ﻻ - ﻧﻈـﺮاً ﻟﺪرﺟﺔ ﺣﺮارﺗﻪ ا ﺮﺗﻔﻌﺔ واﻟﻬﺠﻮم ا ﺴـﺘﻤﺮ ﻟ ﻺﺷﻌﺎع اﻟﻨﺠﻤﻲ واﻟﺮﻳﺎح ﻣﻦ ﻧﺠﻤـﻪ ﺑﻘـﻰ دون إﺟﺎﺑﺔ . ﻗﺎﻟﺖ دﻳﺎﻧﺎ دراﺟﻮﻣ اﻟﺒﺎﺣﺜـﺔ ﰲ اﻟﻜﻮاﻛﺐ اﻟﻨﺠﻤﻴﺔ ﺑﺠﺎﻣﻌﺔ ﻧﻴﻮ ﻣﻜﺴﻴﻜﻮ وا ﺆﻟﻔﺔ ا ﺸﺎرﻛﺔ ﰲ اﻟﺪراﺳﺔ " : ﻟﻘﺪ ﻋﻤﻠـﺖ ﻋﲆ ﻫ ﺬا اﻟﻜﻮﻛﺐ ﻷﻛﺜﺮ ﻣﻦ ﻋﻘﺪ ﻣﻦ اﻟﺰﻣﻦ ". - ﻮﻟﻴﻮ ﻳ ﺃﻏﺴﻄﺲ 2 0 2 4 54