Free Astronomy Magazine September-October 2024

his transmission spectrum, captured using NASA’s Hubble and James Webb space telescopes, shows the amounts of different wavelengths (col-ors) of starlight blocked by the atmosphere of the gas-giant exoplanet WASP-107 b. The spectrum includes light collected over five separate ob- servations using a total of three different instruments: Hubble’s WFC3 (0.8–1.6 microns), Webb’s NIRCam (2.4–4.0 microns and 3.9–5.0 microns), and Webb’s MIRI (5–12 microns). Each set of measurements was made by observing the planet-star system for about 10 hours before, during, and afterthe transit as the planet moved across the face of the star. By comparing the brightness of light filtered through the planet’s atmosphere (transmit- tedlight)tounfilteredstarlight,itispossibletocalculatetheamountofeachwavelengththatisblockedbytheatmosphere.Sinceeachmoleculeab- sorbsauniquecombinationofwavelengths,thetransmissionspectrumcanbeusedtoconstraintheabundanceofvariousgases.Thisspectrum shows clear evidence for water (H 2 O), carbon dioxide (CO 2 ), carbon monoxide (CO), methane (CH 4 ), sulfur dioxide (SO 2 ), and ammonia (NH 3 ) in the planet’s atmosphere, allowing researchers to estimate the interior temperature and mass of the core. This wavelength coverage from optical to mid- infrared is the broadest of any exoplanet transmission spectrum to date, and includes the first reported space telescope detection of ammonia in an exoplanet atmosphere. [NASA, ESA, CSA, Ralf Crawford (STScI) – Luis Welbanks (ASU), JWST MANATEE Team] with the cooler layers higher up,” explained Sing. “Methane is unsta- ble at high temperatures. The fact that we detected so little, even though we did detect other carbon- bearing molecules, tells us that the interioroftheplanetmustbesignif- icantly hotter than we thought.” AlikelysourceofWASP-107b’sextra internal energy is tidal heating caused by its slightly elliptical orbit. Withthedistancebetweenthestar and planet changing continuously overthe5.7-dayorbit,thegravita- tionalpullisalsochanging,stretch- ing the planet and heating it up. Researchershadpreviouslypro- DanielThorngrenfromJHU.Itturns outthatthecoreisatleasttwiceas massive as originally estimated, whichmakesmoresenseintermsof how planets form. All together, WASP-107 b is not asmysterious as it once appeared. “TheWebbdatatellsusthatp lanets like WASP-107 b didn’t have to form in some odd way with a super small core and a huge gassy envelope,” explained Mike Line from ASU. “In- stead, we can take something more like Neptune, with a lot of rock and notasmuchgas,justdialupthe temperature, and poof it up to look theway it does.”     SEPTEMBER-OCTOBER2024 ُﻈﻬـﺮ ـﻒﺣﺎﻟـﺔ اﻟﻌﺒــﻮر ﻃ ﻫـﺬا ـﺐ اﻟﻔﻀــﺎﺋ ﺔ اﻟﺘﺎ ﻌـﺔ ﻟ ﺗـﻢ اﻟﺘﻘﺎﻃــﮫ ﺎﺳـﺘﺨﺪام ﺗﻠﺴـ ﻮ ﺎتﻫﺎﺑـﻞ وﺟــ ﻤﺲو اﻟــﺬ ﻮ ﺎﻟــﺔ ﻧﺎﺳـﺎ ــﺔ اﻟﻤﺨﺘﻠﻔـﺔ ــﺎت اﻷﻃـﻮال اﻟﻤﻮﺟ ﻤ ) اﻷﻟــﻮان ( ﻟﻀـﻮء اﻟـﻨ ﻢ اﻟﻤﺤﺠــﻮب ﺧﻠـﻒ اﻟﻐــﻼف اﻟـ ـ ﺠﻮي ﻟﻠ ﻮﻛــﺐ اﻟ ﻨ ﻤـﻲ اﻟﻐــﺎزي اﻟﻌﻤــﻼق WASP-107 b . ـﺎت رﺻــﺪ ﻣﻨﻔﺼــﻠﺔ ﺎﺳـﺘﺨﺪام ﻣـﺎ ﻣ ﻤﻮﻋـﮫ ﺛـﻼث أدوات ﻣﺨﺘﻠﻔــﺔ ﺗـﻢ ﻤﻌــﮫ ﻋـ ﻤــﺲﻋﻤﻠ ـﻒ اﻟﻀـﻮء اﻟــﺬ ﺘﻀــﻤﻦ اﻟﻄ : و ﺎﻣ ا ﻫﺎﺑﻞ WFC3 ) ﺎﻣ ا واﺳﻌﺔ اﻟﻤﺠﺎل 3 ( 0.8–1.6) و ( ﻣ ﻜﺮون ﺎﻣ ا ﻧ ﺎم – ﺗﻠﺴ ﻮب و ﺐ ) 2.4–4.0 ﻣ ﻜﺮون و 3.9–5.0 ، ( ﻣ ﻜﺮون و ﺎﻣ ا ﻣ ي – ﺗﻠﺴ ﻮب و ﺐ 5–12) ﻣ ﻜﺮون ﺗﻢ (. ــﺔ ﻧﻈـﺎم اﻟ ﻮﻛـﺐ واﻟـﻨ ﻢ ﻟﻤـﺪة ـﻞ ﻣ ﻤﻮﻋـﺔ ﻣـﻦ اﻟﻘ ﺎﺳـﺎت ﻣـﻦ ﺧـﻼل ﻣﺮاﻗ إﺟـﺮاء 10 ـ ﺎً ﺳـﺎﻋﺎت ﺗﻘﺮ ﻗﺒــﻞ وأﺛﻨـﺎء و ﻌـﺪ اﻟﻌﺒـﻮر أﺛﻨـﺎء ﺗﺤـﺮك اﻟ ﻮﻛـﺐ ﻋــ وﺟـﮫ اﻟـﻨ ﻢ و ﻣـﻦ ﺧـﻼل ﻣﻘﺎرـﺔ ﺳـﻄﻮع اﻟﻀــﻮء اﻟﻤ ﺷﺢ ﻋ اﻟﻐﻼف اﻟ ـ ﺠﻮي ﻟﻠ ﻮﻛﺐ ) اﻟﻀﻮء اﻟ ( ﻤﻨﻘﻮل ﻣﻊ ﺿﻮء اﻟﻨﺠﻮم ﻏ اﻟﻤﺮﺷﺢ ﻣﻦ اﻟﻤﻤﻜﻦ ﺣﺴﺎب ﻣﻘﺪار ﻞ ﻃﻮل ﻣﻮﺟﻲ ﻳﺤﺠ ﮫ اﻟﻐﻼف اﻟ ـ ﺠﻮيو ﻤﺎ أن ﻞ ﺟـﺰيء ﻤـﺘﺺﻣﺰ ﺠـ ﺎً اً ﻓﺮ ـﺪ ﻣـﻦ اﻷﻃﻮال اﻟﻤﻮﺟ ﺔ ﻓ ﻤﻜﻦ اﺳﺘﺨﺪامﻃ ﻒ ﺣﺎﻟﺔ ﻋﺒﻮر اﻟ ﻮﻛﺐ أﻣﺎم ﻧ ﻤﮫ ﻟﺘﺤﺪ ﺪ وﻓـﺮة اﻟﻐـﺎزات اﻟﻤﺨﺘﻠﻔـﺔ . ـﻒ دﻟـ ﻼً واﺿـﺤ ﻈﻬـﺮﻫـﺬا اﻟﻄ ﺎً ﻋﻠـﻰ اﻟﻤـﺎء ) H2O ( وﺛـﺎﻧﻲ أﻛﺴـ ﺪ اﻟﻜﺮـﻮن ) CO2 ( وأول أﻛﺴ ﺪ اﻟﻜﺮﻮن واﻟﻤ ﺜﺎن ) CH4 ( وﺛﺎﻧﻲ أﻛﺴ ﺪ اﻟﻜ ﺖ ) SO2 ( واﻷﻣﻮﻧ ﺎ ) NH3 ( ﻓﻲ اﻟﻐﻼف اﻟ ـ ﺠﻮي ﻟﻠ ﻮﻛﺐ ﺘﻘﺪﻳﺮ درﺟﺔ اﻟ ﻣﻤﺎ ﺴﻤﺢ ﻟﻠ ﺎﺣﺜ ـ ﺤﺮارة اﻟﺪاﺧﻠ ﺔ وﻛﺘﻠﺔ اﻟﻨﻮاة . ﺗﻌﺪ ﺗﻐﻄ ﺔ اﻟﻄﻮل اﻟﻤـﻮﺟﻲ ﻣـﻦ اﻷﺷـﻌﺔ ﺗﺤــﺖ اﻟــ ـ ﻤﺮاء اﻟ ﺼــﺮ ﺔ إﻟــﻰ اﻷﺷــﻌﺔ ﺗﺤــﺖ اﻟــ ـ ﻤﺮاء اﻟﻤﺘﻮﺳــﻄﺔ ﻫــﻲ ا ـﻒ ﻷوﺳــﻊ ﻣــﻦ أيﻃ ﺣﺎﻟــﺔ ﻋﺒــﻮر ﻟ ﻮﻛــﺐ ﻧ ﻤــﻲ أﻣــﺎم ﻧ ﻤــﮫ اﻵن ﺣــ وﺗﺘﻀــﻤﻦ أول اﻛﺘﺸــﺎف ﺑﻮاﺳــﻄﺔ ﺗﻠﺴ ﻮب ﻓﻀﺎﺋﻲ ﻟﻸﻣﻮﻧ ﺎ ﻓﻲ اﻟﻐﻼف اﻟ ـ ﺠﻮي ﻟ ﻮﻛﺐﺧﺎرج اﻟﻤ ﻤﻮﻋﺔ اﻟﺸﻤﺴ ﺔ ] . NASA, ESA, CSA, Ralf Crawford (STScI) – LuisWelbanks (A U , JWSTMANATEE Team [ أﻇﻬﺮ ﻛﻼ اﻟﻄﻴﻔ ﻧﻘﺺ ا ﻴﺜﺎن ﰲ اﻟﻐـﻼف اﻟﺠﻮي ﻟﻠﻜﻮﻛﺐ WASP-107 b: وﻫﻮ ﺟـﺰء ﻣﻦ اﻷﻟﻒ ﻣﻦ اﻟﻜﻤﻴـﺔ ا ﺘﻮﻗﻌـﺔ ﺑﻨـﺎء ﻋـﲆ درﺟﺔ ﺣﺮارﺗﻪ ا ﻔﱰﺿـﺔ . أوﺿـﺢ ﺳـﻴﻨﺞ : " ﻫﺬا دﻟﻴﻞ ﻋﲆ أن اﻟﻐﺎز اﻟﺴﺎﺧﻦ اﻟﻘﺎدم ﻣﻦ أﻋﻤﺎق اﻟﻜﻮﻛﺐ ﻳﺠﺐ أن ﻳﻤﺘﺰج ﺑﻘـﻮة ﻣـﻊ اﻟ ﻄﺒﻘﺎت اﻷﻛﺜﺮ ﺑﺮودة ﰲ اﻷﻋﲆ ا ﻴﺜﺎن ﻏـ ﻣﺴــﺘﻘﺮ ﰲ درﺟــﺎت اﻟﺤــﺮارة ا ﺮﺗﻔﻌــﺔ وﺣﻘﻴ ﻘﺔ أﻧﻨﺎ اﻛﺘﺸﻔﻨﺎ اﻟﻘﻠﻴﻞ ﺟﺪ اً ﻋﲆ اﻟﺮﻏﻢ ﻣﻦ أﻧﻨﺎ اﻛﺘﺸﻔﻨﺎ ﺟﺰﻳﺌـﺎت أﺧـﺮى ﺣﺎﻣﻠـﺔ ﻟﻠﻜﺮﺑﻮن ﺗﺨﱪﻧﺎ أن ﺑﺎﻃﻦ اﻟﻜﻮﻛﺐ ﻻ ﺑـﺪ أن ﻳﻜﻮ ن أﻛﺜﺮ ﺳﺨﻮﻧﺔ ﺑﻜﺜ ﻣﻤﺎ ﻛﻨـﺎ ﻧﻌﺘﻘـ ﺪ ﻳﺤﺘﻤﻞ أن ﻳﻜﻮن ﻣﺼﺪر اﻟﻄﺎﻗـﺔ اﻟﺪاﺧﻠﻴـﺔ اﻹﺿــﺎﻓﻴﺔ ﻟﻠﻜﻮﻛــﺐ WASP-107b ﻫــﻮ ﺗﺴـﺨ ا ـﺪ واﻟﺠـﺰر ا ﻟﻨـﺎﺗﺞ ﻋـﻦ ﻣـﺪاره اﻹﻫﻠﻴﻠﺠ ـﻲ ﻟﻠﻜﺮﺑ ـﻮن، ﺗﺨﱪﻧ ـﺎ أن ﺑ ـﺎﻃﻦ اﻻﻫﻠﻴﺠﻲ وﻣﻊ ﺗﻐـ ا ﺴـﺎﻓﺔ ﺑـ اﻟـﻨﺠﻢ واﻟﻜﻮﻛ ﺐ ﺑﺸﻜﻞ ﻣﺴﺘﻤﺮ ﻋﲆ ﻣﺪار 5.7 ﻳﻮﻣﺎً ﺗﺘﻐ ﻗﻮى اﻟﺠﺎذﺑ ﻴﺔ أﻳﻀـﺎُ ﻣ ﻤـﺎ ﻳـﺆدي إﱃ ﺗﻤﺪد اﻟﻜﻮﻛﺐ وﺗﺴـﺨﻴﻨﻪ . ﻛـﺎن اﻟﺒـﺎﺣﺜﻮن اﻓﱰﺿﻮا ﺎً ﺳﺎﺑﻘ أن ﺗﺴﺨ ا ﺪ واﻟﺠﺰر ﻗـﺪ ﻳﻜﻮن ﺳﺒﺒ ﺎً ﻟﺘﻀـﺨﻢ WASP-107b وﻟﻜـﻦ ﺣﺘﻰ ﻇﻬﺮت ﻧﺘﺎﺋﺞ ﺗﻠﺴﻜﻮب وﻳﺐ ﻟﻢ ﻳﻜـﻦ ﻫﻨـﺎك أي دﻟﻴ ـﻞ وﺑﻤﺠـﺮد اﻟﺘﺄﻛـﺪ ﻣ ـﻦ أن اﻟﻜﻮﻛﺐ ﻟﺪﻳﻪ ﻣﺎ ﻳﻜﻔﻲ ﻣﻦ اﻟﺤﺮارة اﻟﺪاﺧﻠﻴﺔ ﻟﺘﺤﺮﻳﻚ اﻟﻐﻼف اﻟﺠﻮي ﺑﺸـﻜﻞ ﻛﺎﻣـﻞ أدرك اﻟﻔﺮﻳﻖ أن اﻷﻃﻴﺎف ﻳﻤﻜـﻦ أن ﺗـﻮﻓﺮ أﻳﻀًـﺎ ﻃﺮﻳﻘﺔ ﺟﺪﻳﺪة ﻟﺘﻘـﺪﻳﺮ ﺣﺠـﻢ اﻟﻨـﻮاة إذا ». ﻣﻘﺪ ﻋﺮﻓﻨﺎ ار اﻟﻄﺎﻗﺔ ا ﻮﺟـﻮدة ﰲ اﻟﻜﻮﻛـﺐ وﻋﺮﻓﻨﺎ ﻣﺎ ﻫﻲ ﻧﺴﺒﺔ اﻟﻌﻨﺎﴏ اﻷﺛﻘﻞ ﻣﺜـﻞ اﻟﻜﺮﺑﻮن واﻟﻨﻴﱰوﺟ واﻷﻛﺴﺠ واﻟﻜﱪﻳﺖ ﰲ اﻟﻜﻮﻛ ـﺐ، ﻣﻘﺎﺑ ـﻞ ﻛﻤﻴ ـﺔ اﻟﻬﻴ ـﺪروﺟ ﰲ اﻟﻜﻮﻛــﺐ ﻣﻘﺎﺑــﻞ ﻛﻤﻴــﺔ اﻟﻬﻴــﺪروﺟ اﻟﻬﻴﻠﻴﻮم و ﻳﻤﻜﻨﻨﺎ ﺣﺴﺎب ﻣﻘﺪار ا ﻟﻜﺘﻠﺔ اﻟﺘﻲ ﻳﺠﺐ أن ﺗﻜـﻮن ﰲ اﻟ ﻨـﻮاة « أوﺿـﺢ داﻧﻴﻴـﻞ ﺛﻮرﻧﺠﺮﻳﻦ : ﻟﻘﺪ ﺗﺒ أن ﻛﺘﻠﺔ اﻟﻨـﻮاة ﺗﺒﻠـﻎ ﺿﻌﻔﻲ اﻟﻜﺘﻠﺔ ﻋﲆ اﻷﻗﻞ ﻛﻤﺎ ﺗﻢ ﺗﻘﺪﻳﺮﻫﺎ ﰲ اﻷﺻﻞ، ﻣﻤﺎ ﻳﺠﻌﻞ اﻷﺟـﺰاء اﻟﺪاﺧﻠﻴـﺔ أﻛﺜـﺮ ﻣﻨﻄﻘﻴﺔ ﺣﻮل ﻛﻴﻔﻴﺔ ﺗﺸﻜﻞ اﻟﻜﻮاﻛﺐ . ﻳﻘﻮل ﻣﺎﻳﻚ ﻻﻳﻦ ﻣﻦ ﺟﺎﻣﻌﺔ وﻻﻳﺔ أرﻳﺰوﻧـﺎ : " ﺗﺨﱪﻧﺎ ﺑﻴﺎﻧﺎت ﺗﻠﺴﻜﻮب وﻳﺐ أن اﻟﻜﻮاﻛﺐ ﻣﺜﻞ WASP-107 b ﻟﻢ ﻳﻜﻦ ﻣﻦ اﻟ ـ ﴬوري أن ﺗﺘﺸﻜﻞ ﺑﻄﺮﻳﻘﺔ ﻏﺮﻳﺒﺔ ﻣﻊ ﻧﻮاة ﺻـﻐ ة ﻟﻠﻐﺎﻳﺔ وﻏﻼف ﻏﺎزي ﺿﺨﻢ وﻟﻜﻦ ﻳﻤﻜﻨﻨﺎ أن ﻧﺄﺧﺬ ﺷـﻴﺌًﺎ ﻮن ﻧﺒﺘـ ﻣﺜـﻞ ﺑـﻪ اﻟﻜﺜـ ﻣـﻦ اﻟﺼﺨﻮر وﻟﻴﺲ اﻟﻜﺜـ ﻣـﻦ اﻟﻐـﺎز ، ﻓﻘـﻂ ﻧﻘﻴﺲ درﺟﺔ ﺣﺮارﺗﻪ ﻟﻔﻬﻢ ﻃﺒﻴﻌﺘﻪ . - ﺳﺒﺘﻤﺒﺮ ﺃﻛﺘﻮﺑﺮ 2 0 2 4