Free Astronomy Magazine May-June 2024 ARABIC VERSION

theseandothermolecules detected there by Webb representkeyingredients for making potentially habitable worlds. An international team of astronomers used Webb’s MIRI (Mid-Infrared Instru- ment) to identify a variety oficycompoundsmade up of complex organic molecules like ethanol (al- cohol) and likely acetic acid (an ingredient in vinegar). This work builds on previous Webb detec- tionsofdiverseicesin a cold, dark molecular cloud. “This finding con- tributes to one of thelong- standingquestionsin astrochemistry,” said team leader Will Rocha of Leiden University in the Netherlands. “What is the origin of complex organic molecules, or COMs, in space? Are they made in the gas phase or in ices? The detection of COMs in icessuggeststhatsolid- phasechemicalreactionsonthesur- faces of cold dust grains can build complex kinds of molecules.” As several COMs, including those detected in the solid phase in this research,werepreviouslydetected inthewarmgasphase,itisnowbe- lieved that they originate from the sublimation of ices. Sublimation is tochangedirectlyfromasolidtoa gas without becoming a liquid. Therefore, detecting COMs in ices makes astronomers hopeful about improvedunderstandingoftheori- ginsofother,evenlargermolecules in space. Scientistsarealsokeentoexploreto what extent these COMs are trans- ported to planets at much later stages of protostellar evolution. COMsincoldicesarethoughttobe easier to transport from molecular cloudstoplanet-formingdisksthan warm, gaseous molecules. These icy COMs can therefore be incorpo- rated into comets and asteroids, whichinturnmaycollidewithform- ing planets, delivering the ingredi- ents for life to possibly flourish. The science team also detected sim- pler molecules, including formic acid(whichcausestheburningsen- sation of an ant sting), methane, formaldehyde, and sulfur dioxide. Research suggests that sulfur-con- tainingcompoundslikesulfurdiox- ide played an important role in driving metabolic reactions on the primitive Earth. Of particular interest is that one of the sources investigated, IRAS 2A, is characterizedasalow-massproto- star.IRAS2Amaythereforebesim- ilar to the early stages of our own solar system. As such, the chemicals identified around this protostar may have been present in the first stages of development of our solar system and later delivered to the primitive Earth. “Allofthesemoleculescanbecome part of comets and asteroids and eventually new planetary systems when the icy material is transported inward to the planet-forming disk as the protostellar system evolves,” said Ewine van Dishoeck of Leiden University, one of the coordinators of the science program. “We look forward to following this astro- chemical trail step-by-step with more Webb data in the coming yearsfromORCs.”     ﻣﺠﻠﺔ FreeAstronomy ﺎﻟﻌﺮ ﺔ 49 ﺗﻤﺜﻞ ﻫﺬه اﻟﺠﺰﻳﺌﺎت وﻏ ﻫﺎ اﻟﺘﻲ اﻛﺘﺸـــﻔﻬﺎ وﻳـــﺐ ا ﻜﻮﻧـــﺎت اﻷﺳﺎﺳﻴﺔ ﻟﺼﻨﻊ ﻋﻮاﻟﻢ ﻳﺤﺘﻤﻞ أن ﺗﻜﻮن ﺻﺎﻟﺤﺔ ﻟﻠﺤﻴﺎة . اﺳﺘﺨﺪم ﻓﺮﻳﻖ دوﱄ ﻣـﻦ ﻋﻠﻤـﺎء اﻟﻔﻠﻚ ﻛﺎﻣ ا ﻣ ي ) أداة اﻷﺷـﻌﺔ ﺗﺤــﺖ اﻟﺤﻤــﺮاء ا ﺘﻮﺳــﻄﺔ ( ﻟﺘﻠﺴـﻜﻮب وﻳـﺐ ﻟﻠﺘﻌـﺮف ﻋـﲆ ﻣﺠﻤﻮﻋﺔ ﻣﺘﻨﻮﻋﺔ ﻣـﻦ ا ﺮﻛﺒـﺎت اﻟﺠﻠﻴﺪﻳﺔ ا ﻜﻮﻧـﺔ ﻣـﻦ ﺟﺰﻳﺌـﺎت ﻋ ﻀﻮﻳﺔ ﻣﻌﻘـﺪة ﻣﺜـﻞ اﻹﻳﺜـﺎﻧﻮل ) اﻟﻜﺤﻮل ( وﻣﻦ ا ﺤﺘﻤﻞ ﺣﻤـﺾ اﻷﺳﻴﺘﻴﻚ ) أﺣﺪ ﻣﻜﻮﻧﺎت اﻟﺨﻞ .( ﻳﻌﺘﻤﺪ ﻫﺬا اﻟﻌﻤﻞ ﻋﲆ اﻛﺘﺸﺎﻓﺎت وﻳﺐ اﻟﺴﺎﺑﻘﺔ ﻟﻜﺎﺋﻨـﺎت ﻣﺘﻨﻮﻋـﺔ ﰲ ﺳـــﺤﺎﺑﺔ ﺟﺰﻳﺌﻴـــﺔ ﺑـــﺎردة وﻣﻈﻠﻤﺔ . وﻗﺎل ﻗﺎﺋﺪ اﻟﻔﺮﻳﻖ وﻳﻞ روﺷﺎ ﻣﻦ ﺟﺎﻣﻌﺔ ﻟﻴﺪن ﰲ ﻫﻮﻟﻨﺪا : " إن ﻫﺬا اﻻﻛﺘﺸﺎف ﻳﺴﺎﻫﻢ ﰲ أﺣﺪ اﻷﺳــﺌﻠﺔ اﻟﻘ ﺪﻳﻤــﺔ ﰲ اﻟﻜﻴﻤﻴــﺎء اﻟﻔﻠﻜﻴﺔ ﻣﺎ ﻫ ". ﻮ أﺻﻞ اﻟﺠﺰﻳﺌـﺎت اﻟﻌﻀﻮﻳﺔ ا ﻌﻘﺪة ﰲ اﻟﻔﻀﺎء؟ ﻫﻞ ﻳﺘﻢ ﺗﺼﻨﻴﻌﻬﺎ ﰲ اﻟﻄﻮر اﻟﻐﺎزي أم ﰲ اﻟﺠﻠﻴــﺪ؟ وﻳﺸــ اﻛﺘﺸــﺎف اﻟﺠﺰﻳﺌﺎت COM ﰲ اﻟﺠﻠﻴـﺪ إﱃ أن ﺣﺪدت ﺎﻣ ا ﻣـ ي ) أداة اﻷﺷـﻌﺔ ﺗﺤـﺖ ا ﻤـﺮاء اﻟﻤﺘﻮﺳـﻄﺔ ( ـﺐ اﻟﻔﻀـﺎﺋﻲ اﻟﺘـﺎﺑﻊ ﻟﻨﺎﺳـﺎ اﻟﺘﺎ ﻌـﺔ ﻟﺘﻠﺴـ ﻮبﺟـ ﻤﺲو ﻣ ﻤﻮﻋـــﺔ ﻛﺒـــ ة ﻣـــﻦ ا ﺰ ﺌـــﺎت اﻟﻤ ـــﺔ ﻋﻠـــﻰ اﻟﻜﺮـــﻮن ﻌﻘـــﺪة اﻟﻤﺤﺘﻮ ) اﻟﻌﻀـــﻮ ﺔ ( أوﻟﻴـــ اﻟﻤﺤ ﻄـــﺔ ﻨ ﻤـــ . ُﻈﻬـــﺮﻫـــﺬا اﻷوﻟﻴـــ ـــﻒ أﺣـــﺪ اﻟﻨ ﻤـــ اﻟﺮﺳـــﻢﻃ IRAS 2A وﻫـــﻮ ﺸـــﺘﻤﻞ ﻋﻠـــﻰ ﺼـــﻤﺎت اﻷﺻـــﺎ ﺑﻊ ﻣـــﻦ اﻷﺳـــ ﺘﺎﻟﺪﻳﻬ ﺪ، واﻹ ﺜـــﺎﻧﻮل وﻓﻮرﻣﺎت اﻟﻤ ﺜﻴﻞ و ﻤﺾ اﻟـ ـ ﺨﻠ ﻚ اﻟﻤﺤﺘﻤـﻞ ﻓـﻲ اﻟﻄـﻮراﻟﺼـﻠﺐ . اﻛﺘﺸـﻔﻬﺎ ﺗﻤﺜـﻞ ﻫـﺬﻩ ا ﺰ ﺌـﺎت وﻏ ﻫـﺎ اﻟـ ﺗﻠﺴـ ﻮب و ﺐ ﻣ ﻮﻧﺎت أﺳﺎﺳ ﺔ ﻟﺼﻨﻊ ﻋﻮاﻟﻢ ﻳﺤﺘﻤﻞ أن ﺗ ﻮن ﺻﺎﻟ ـ ﺤﺔ ﻟﻠﺤ ﺎة . اﻟﻌﻀﻮﻳﺔ ا ﻌﻘ ة ﰲ اﻟﺠﻠﻴـﺪ إﱃ أن اﻟﺘﻔﺎﻋﻼت اﻟﻜﻴﻤﻴﺎﺋﻴﺔ ﰲ اﻟﻄﻮر اﻟﺼـﻠﺐ ﻋـﲆ أﺳﻄﺢ ﺣﺒﻴﺒﺎت اﻟﻐﺒﺎر اﻟﺒـﺎرد ﻳﻤﻜﻨﻬـﺎ ﺑﻨـﺎء أﻧﻮاع ﻣﻌﻘﺪة ﻣﻦ اﻟﺠﺰﻳﺌﺎت . ﺑﻤﺎ أن اﻟﻌﺪﻳﺪ ﻣﻦ اﻟﺠﺰﻳﺌﺎت اﻟﻌﻀﻮﻳﺔ ا ﻌﻘﺪة ﺑﻤﺎ ﰲ ذﻟـﻚ ﺗﻠـﻚ ا ﻜﺘ ﺸﻔﺔ ﰲ اﻟﻄﻮر اﻟﺼﻠﺐ ﰲ ﻫﺬا اﻟﺒﺤﺚ ﺗـﻢ اﻛﺘﺸﺎﻓ ﺎً ﻬﺎ ﺳﺎﺑﻘ ﰲ اﻟﻄـﻮر اﻟﻐـﺎزي اﻟـﺪاﻓﺊ ﻳُﻌﺘﻘﺪ اﻵن أﻧﻬﺎ ﺗﻨﺸـﺄ ﻣـﻦ ﺗﺴـﺎﻣﻲ اﻟﺠﻠﻴـﺪ . اﻟﺘﺴﺎﻣﻲ ﻫﻮ اﻟﺘﺤـﻮل ﻣﺒـﺎﴍة ﻣـﻦ اﻟﺤﺎﻟـﺔ اﻟﺼـﻠﺒﺔ إﱃ اﻟﻐـﺎز دون أن ﺗﺘ ﺤـﻮل إﱃ ﺣﺎﻟـﺔ ﺳﺎﺋﻠﺔ وﻟﺬﻟﻚ، ﻓـﺈن اﻟﻜﺸـﻒ ﻋـﻦ اﻟﺠﺰﻳﺌـﺎت اﻟﻌﻀﻮﻳﺔ ا ﻌﻘﺪة ﰲ اﻟﺠﻠﻴﺪ ﻳﺠﻌﻞ ﻋﻠﻤﺎء اﻟﻔﻠﻚ ﻣﺘﻔﺎﺋﻠ ﺑﺸﺄن ﺗﺤﺴ ﻓﻬﻢ أﺻﻮل اﻟﺠ ﺰﻳﺌﺎت اﻷﺧﺮى وﺣﺘﻰ اﻷﻛﱪ ﺣﺠﻤﺎ . ﰲ اﻟﻔﻀﺎء وﻳﺤﺮص اﻟﻌﻠﻤﺎء أﻳﻀًﺎ ﻋﲆ اﺳﺘﻜﺸﺎف ﻣـﺪى اﻧﺘﻘﺎل ﻫﺬه اﻟﻌﻨﺎﴏ إﱃ اﻟﻜﻮاﻛـﺐ ﰲ ﻣﺮاﺣـﻞ ﻻﺣﻘﺔ ﻣﻦ ﺗﻄﻮر اﻟﻨﺠﻮم اﻷوﻟﻴﺔ . ﻻﺣﻘﺔ ﻣﻦ ﺗﻄﻮر اﻟﻨﺠﻮم اﻷوﻟﻴـﺔ و ﻳُﻌﺘﻘـﺪ أن ﻧﻘﻞ اﻟﺠﺰﻳﺌﺎت اﻟﻌﻀﻮﻳﺔ ا ﻌﻘﺪة ا ﻮﺟـﻮد ﰲ ة اﻟﱪ ةدو اﻟﺴﺤﺐ اﻟﺠﺰﻳﺌﻴﺔ إﱃ اﻷﻗﺮاص ا ﻜﻮﻧﺔ ﻟﻠﻜﻮاﻛﺐ أﺳﻬﻞ ﻣﻦ ﻧﻘﻞ اﻟﺠﺰﻳﺌـﺎت اﻟﻐﺎزﻳـﺔ اﻟﺪاﻓﺌﺔ وﻣﻦ ﺛﻢ ﻳﻤﻜﻦ دﻣـﺞ ﻫـﺬه ا ﺮﻛﺒـﺎت اﻟﺠﻠﻴﺪﻳﺔ ﰲ ا ـﺬﻧﺒﺎت واﻟﻜﻮﻳﻜﺒـﺎت اﻟﺘـﻲ ﻗـﺪ ﺗﺼﻄﺪم ﺑـﺪورﻫﺎ ﺑﺎﻟﻜﻮاﻛـﺐ ا ﺘﺸـﻜﻠﺔ ﻣﻤـﺎ ﻳـﻮﻓﺮ ا ﻜﻮﻧـﺎت اﻟﻼزﻣـﺔ ﻻزدﻫـﺎر اﻟﺤﻴــﺎة . اﻛﺘﺸﻒ اﻟﻔﺮﻳﻖ اﻟﻌﻠﻤﻲ أﻳﻀًﺎ ﺟﺰﻳﺌﺎت أﺑﺴـﻂ ﺑﻤﺎ ﰲ ذﻟﻚ ﺣﻤﺾ اﻟﻔﻮرﻣﻴـﻚ ) اﻟـﺬي ﻳﺴـﺒﺐ اﻹﺣﺴﺎس ﺑﺎﻟﺤﺮﻗﺎن اﻟﻨﺎﺗﺞ ﻋﻦ ﻟﺪﻏﺔ اﻟﻨﻤـﻞ ( وا ﻴﺜــﺎن واﻟﻔﻮ رﻣﺎﻟﺪﻫﻴــﺪ وﺛــﺎﻧﻲ أﻛﺴــﻴﺪ اﻟﻜﱪﻳــﺖ . ﺗﺸــ اﻷﺑﺤــﺎث إﱃ أ ن ا ﺮﻛﺒ ـﺎت ا ﺤﺘﻮﻳﺔ ﻋـﲆ اﻟﻜﱪﻳـﺖ ﻣﺜـﻞ ﺛـﺎﻧﻲ أﻛﺴـﻴﺪ اﻟﻜﱪﻳﺖ ﻟﻌﺒﺖ دورا ﻣﻬﻤﺎ ﰲ ﺗﺤﻔﻴﺰ اﻟﺘﻔﺎ ﻋﻼت اﻷﻳﻀـﻴﺔ ﻋـﲆ اﻷرض اﻟﺒﺪاﺋﻴـﺔ ، وﻣﻤــﺎ ﻳﺜـ اﻻﻫﺘﻤﺎ م اﻻﻫﺘﻤﺎ ﻪ أﻧـ م ﻋﻨـﺪ ﻓﺤـﺺ IRAS 2A اﻟـﺬي ﻳ ﺘﻤﻴﺰ ﺑﺄﻧﻪ ﻧﺠـﻢ أوﱄ ﻣـﻨﺨﻔﺾ اﻟﻜﺘﻠـﺔ ﻗـﺪ ﻳﻜــﻮن ﻣﺸــﺎﺑﻬًﺎ ﻟﻠﻤﺮاﺣــﻞ اﻷوﱃ ﻟﻨﻈﺎﻣﻨــﺎ اﻟﺸ و ﻤﴘـ رﺑﻤﺎ ﻛﺎﻧﺖ ا ﻮاد اﻟﻜﻴﻤﻴﺎﺋﻴﺔ ﺣﻮل ﻫﺬا اﻟﻨﺠﻢ اﻷوﱄ ﻣﻮﺟﻮدة ﰲ ا ﺮاﺣﻞ اﻷوﱃ ﻣﻦ ﺗﻄﻮر ﻧﻈﺎﻣﻨﺎ اﻟ ﻤﴘـﺸ ووﺻـﻠﺖ ﻻﺣﻘًـﺎ إﱃ اﻷرض اﻟﺒﺪاﺋﻴﺔ ﻗﺎ . ل إوﻳﻦ ﻓﺎن دﻳﺸـﻮك ﻣـﻦ ﺟﺎﻣﻌﺔ ﻻﻳﺪن أﺣﺪ ﻣﻨﺴﻘﻲ اﻟﱪﻧﺎﻣﺞ اﻟﻌﻠﻤـﻲ : " ﺟﻤﻴﻊ ﻫﺬه اﻟﺠﺰﻳﺌﺎت ﻳﻤﻜﻦ أن ﺗﺼﺒﺢ ﺟﺰءًا ﻣﻦ ا ﺬﻧﺒﺎت واﻟﻜﻮﻳﻜﺒﺎت وﰲ اﻟﻨﻬﺎﻳﺔ أﻧﻈﻤـﺔ ﻛﻮﻛﺒﻴﺔ ﺟﺪﻳﺪة ﻋﻨﺪﻣﺎ ﺗﻨﺘﻘﻞ ا ـﻮاد اﻟﺠﻠﻴﺪﻳـﺔ ﻧﺤﻮ اﻟﺪاﺧﻞ إﱃ اﻟﻘﺮص اﻟﺬي ﻳﺸﻜﻞ اﻟﻜﻮﻛـ ﺐ ﻣﻊ ﺗﻄﻮر اﻟﻨﻈﺎم اﻟﻨﺠﻤﻲ اﻷوﱄ ." ﻧﺘﻄﻠﻊ ﺘﺎﺑﻌﺔ ﻫﺬا ا ﺴﺎر اﻟﻜﻴﻤﻴﺎﺋﻲ اﻟﻔﻠﻜـﻲ ﻣـﻊ ا ﺰﻳـﺪ ﻣـﻦ ﺑﻴﺎﻧـﺎت ﺗﻠﺴـﻜﻮب وﻳـﺐ ﰲ اﻟﺴﻨﻮات اﻟﻘﺎدﻣﺔ . - ﻣﺎﻳﻮ ﻳﻮﻧﻴﻮ 2 0 2 4