Free Astronomy Magazine September-October 2024

Using Webb’s NIRSpec (Near-In- frared Spectrograph), astronomers confirmed a temperature difference between the eternal morning and eternal evening on WASP-39 b, with the evening appearing hotter by roughly 300 Fahrenheit degrees (about 200 Celsius degrees). They also found evidence for different cloud cover, with the forever morn- ingportionoftheplanetbeing likely cloudier than the evening. Astronomers analyzed the 2- to 5- micron transmission spectrum of WASP-39 b, a technique that stud- ies the exoplanet’s terminator, the boundarythatseparatestheplanet’s dayside and nightside. A transmis- sion spectrum is made by comparing starlight filtered through a planet’s atmosphere as it moves in front of the star, to the unfiltered starlight detected when the planet is beside the star. When making that compar- ison, researchers can get informa- tion about the temperature, com- position, and other properties of the planet’s atmosphere. “WASP-39 b has become a sort of benchmark planet in studying the atmosphere of exoplanets with Webb,” said Néstor Espinoza, an exoplanet researcher at the Space Telescope ScienceInstitute andlead author on the study. “It has an in- flated,puffyatmosphere,sothesig- nal coming from starlight filtered through the planet’s atmosphere is quite strong.” Previously published Webb spectra of WASP-39b’s atmosphere, which revealed the presence of carbon dioxide, sulfur dioxide, water vapor, and sodium, represent the entire day/night boundary – there was no detailed attempt to differentiate between one side and the other. Now, the new analysis builds two different spectra from the termina- tor region, essentially splitting the day/nightboundaryintotwosem ﻣﺠﻠﺔ FreeAstronomy ﺎﻟﻌﺮ ﺔ 25 ُ ﻈﻬــﺮ اﻟﻀـﻮء ﻣﻨﺤــ ــﺎف ﺑﻮاﺳــﻄﺔ ﻣﻄ ﻧ ﺳــﺒ ﻚ ﻟ ﻸﺷــﻌﺔ ﺗﺤــﺖ اﻟــ ـ ــﺔ ﻤﺮاء اﻟﻘﺮ اﻟﺘــﺎﺑﻊ ﻟ ــﺐ اﻟﻔﻀــﺎﺋﻲ اﻟﺘﻐــ ﻓــﻲ اﻟﺴــﻄﻮع ﻣــﻦ ﺘﻠﺴــ ﻮب و اﻟ ﻨﻈــﺎم اﻟﻨ ﻤــﻲ WASP-39 أﺛﻨـﺎء ﻋﺒــﻮر اﻟ ﻮﻛــﺐ أﻣــﺎم اﻟــﻨ ﻢ . ﺗــﻢ إﺟــﺮاء اﻟﺮﺻــﺪ ﺎﺳـﺘﺨﺪام وﺿـﻌ ﺔ اﻟﺴﻠﺴــﻠﺔ ــﺔ ﻟﻸﺟﺴـﺎم اﻟﺴــﺎﻃﻌﺔ اﻟﺰﻣﻨ ـﺎف ﻟﻤﻄ ﻧ ﺳــﺒ ﻚ ﺴــﺘﺨﺪم واﻟــﺬ اﻟﺘﺸﺘﺖ ﻟﻨﺸﺮ اﻟﻀﻮء ﻣﻦ ﺟﺴﻢﺳﺎﻃﻊ واﺣﺪ ) ﻣﺜﻞ اﻟﻨ ﻢ اﻟﻤﻀ ﻒ ﻟ ﻠ ﻮﻛﺐ WASP-39b ( وﻗ ﺎسﺳﻄﻮع ﻞ ﻃﻮل ﻣﻮﺟﺔ ﻟﻠﻀﻮء ﻓﻲﻓ ة زﻣﻨ ﺔ ﻣﺤﺪدة . - ﺳﺒﺘﻤﺒﺮ ﺃﻛﺘﻮﺑﺮ 2 0 2 4 ﺑﺎﺳﺘﺨﺪام ﻣﻄﻴﺎف ﻧ ﺳﺒﻴﻚ ﻟ ﻸﺷﻌﺔ ﺗﺤـﺖ اﻟﺤﻤﺮاء اﻟﻘﺮﻳﺒﺔ ﻋﲆ ﻣﺘﻦ ﺗﻠﺴـﻜﻮب وﻳـﺐ أﻛـﺪ ﻋﻠﻤـﺎء اﻟﻔﻠـﻚ وﺟـﻮد ﻓـﺮق ﰲ درﺟـﺔ اﻟﺤﺮارة ﺑ اﻟﺼﺒﺎح اﻷﺑﺪي وا ﺴﺎء اﻷﺑـﺪي ﻋﲆ اﻟﻜﻮﻛﺐ WASP-39 b ﺣﻴﺚ ﺑﺪا ا ﺴﺎء أﻛﺜﺮ ﺳﺨﻮﻧﺔ ﺑﻨﺤﻮ 300 درﺟﺔ ﻓﻬﺮﻧﻬﺎﻳـﺖ ﺣﻮاﱄ ) 200 درﺟﺔ ﻣﺌﻮﻳﺔ و( وﺟـﺪوا أﻳﻀـ ﺎ أدﻟﺔ ﻋﲆ وﺟﻮد ﻏﻄﺎء ﺳﺤﺎﺑﻲ ﻣﺨﺘﻠﻒ ﺣﻴﺚ ﻣﻦ ا ﺤﺘﻤـﻞ أن ﻳﻜـﻮن اﻟﺠـﺰء اﻟﺼـ ﺒﺎﺣﻲ اﻟﺪاﺋﻢ ﻣﻦ اﻟﻜﻮﻛﺐ أﻛﺜﺮ ﻏﻴﻮﻣ ﺎ ﻣﻦ ا ﺴﺎء . ﻟﻘﺪ ﻗﺎم ﻋﻠﻤﺎء اﻟﻔﻠﻚ ﺑﺈﺟﺮاء ﺗﺤﻠﻴـﻞ ﻃﻴـﻒ اﻹرﺳﺎل ﻣﻦ 2 ﻰ ـإﻟ 5 ﻣﻴﻜﺮون ﻟـ WASP- 39 وﻫـﻲ ﺗﻘﻨﻴــﺔ ﺗـﺪرس اﻟﺤـﺪ اﻟﻔﺎﺻـﻞ ﻟﻠﻜﻮﻛﺐ ﻟﻠﻜﻮﻛﺐ اﻟ ﻨﺠﻤﻲ اﻟﺬي ﻳﻔﺼﻞ ﺑـ اﻟﺠﺎﻧـﺐ اﻟﻨﻬﺎري واﻟﻠﻴﲇ ﻟﻠﻜﻮﻛﺐ ﻳ. ﺘﻢ إﺟﺮاء ﻃﻴـﻒ اﻹرﺳﺎل ﻣﻦ ﺧﻼل ﻣﻘﺎرﻧـﺔ ﺿـﻮء اﻟﻨﺠـﻮم ا ﺮﺷّﺢ ﻋﱪ اﻟﻐﻼف اﻟﺠﻮ ي ﻟﻠﻜﻮﻛـﺐ أﺛﻨـﺎء ﺗﺤﺮﻛﻪ أﻣﺎم اﻟﻨﺠﻢ ﻣﻊ ﻢ ﺿـﻮء اﻟـﻨﺠ ﻏـ ا ﺮﺷّﺢ اﻟﺬي ﻳﺘﻢ اﻛﺘﺸـﺎﻓﻪ ﻋﻨـﺪﻣﺎ ﻳﻜـﻮن اﻟﻜﻮﻛﺐ ﺑﺠﺎﻧﺐ اﻟﻨﺠﻢ . ﻋﻨﺪ اﻟﻘﻴﺎم ﺑـ ﺈﺟﺮاء ﻫﺬه ا ﻘﺎرﻧﺔ ﻳﺴﺘﻄﻴﻊ اﻟﺒﺎﺣﺜﻮن اﻟﺤﺼـﻮل ﻋــﲆ ﻣﻌﻠ ﻮﻣــﺎت ﺣــﻮل درﺟــﺔ اﻟﺤــﺮارة واﻟﱰﻛﻴﺐ وﻏ ﻫﺎ ﻣـﻦ ﺧﺼـﺎﺋﺺ اﻟﻐـﻼف اﻟﺠﻮي ﻟﻠﻜﻮﻛﺐ . ﻗﺎل ﻧﻴﺴﺘﻮر إﺳﺒﻴﻨﻮزا اﻟﺒﺎﺣﺚ ﰲ اﻟﻜﻮاﻛـﺐ اﻟﻨﺠﻤﻴﺔ ﰲ ﻣﻌﻬﺪ ﻋﻠﻮم اﻟﺘﻠﺴﻜﻮب اﻟﻔﻀﺎﺋﻲ وا ﺆﻟﻒ اﻟﺮﺋﻴﴘ ﻟﻠﺪراﺳﺔ " : أﺻﺒﺢ WASP- 39 b ﺑﻤﺜﺎﺑـﺔ ﻛﻮﻛـﺐ ﻣﺮﺟﻌـﻲ ﰲ دراﺳــﺔ اﻟﻐﻼف اﻟﺠﻮي ﻟﻠﻜﻮاﻛﺐ اﻟﻨﺠﻤﻴﺔ ﺑﺎﺳﺘﺨﺪام ﺗﻠﺴـﻜﻮب " ". وﻳـﺐ إﻧـﻪ ذو ﻏــﻼف ﺟـﻮي ﻣﻨﺘﻔﺦ وﺑﺪﻳﻦ ﻟﺬا ﻓﺈن اﻹﺷﺎرة اﻟﻘﺎدﻣﺔ ﻣﻦ ﺿﻮء اﻟﻨﺠﻮم ا ﺘﴪب ﻋﱪ اﻟﻐـﻼف اﻟﺠـﻮي ﻟﻠﻜﻮﻛﺐ ﻗﻮﻳﺔ ﺟﺪ ."اً ﺗﻤﺜﻞ أﻃﻴﺎف وﻳﺐ ا ﻨﺸﻮرة ﺳﺎﺑﻘ ﺎً ﻟﻠﻐـﻼف اﻟﺠﻮي ﻟـ WASP-39b واﻟﺘﻲ ﻛﺸﻔﺖ ﻋـﻦ وﺟﻮد ﺛﺎﻧﻲ أﻛﺴﻴﺪ اﻟﻜﺮﺑﻮن وﺛـﺎﻧﻲ أﻛﺴـﻴ ﺪ اﻟﻜﱪﻳﺖ وﺑﺨـﺎر ا ـﺎء واﻟﺼـﻮدﻳﻮم ﺣـﺪود اﻟﻨﻬـﺎر واﻟﻠﻴـﻞ ﺑﺄﻛﻤﻠﻬـﺎ وﻟـﻢ ﺗﻜـﻦ ﻫﻨـﺎك ﻣﺤﺎوﻟﺔ ﺗﻔﺼﻴﻠﻴﺔ ﻟﻠﺘﻤﻴﻴﺰ ﺑ ﺟﺎﻧﺐ وآﺧﺮ .