Free Astronomy Magazine January-February 2025 ARABIC VERSION

searchers found that the external protoplanetarydiscsurroundingthis star is miss-aligned, and is seen al- most face on, instead of being in a moreinclinedpositionwhichismore usual statistically. In addition they detected a very weak inner disc. This combination allowed them to observerthetransitingprotoplanet IRAS 04125+2902 b. The study showed that this planet has an or- bitalperiodof8.83days,aradius 10.7 times bigger than that of the Earth,andhasamassapproximately 30%ofthemassofJupiter.Theau- thorsofthearticlesuggestthatthebab yplanetorprotoplanetcouldbe a predecessor to “super-Earths” or to“sub-Neptunes”,whichareoften foundorbitingstarsonthemainse- quence:thosewhichareburninghy- drogen.Theyinferthisbecausethe planetisstillintheprocessofcon- traction,anditsfinalsizeisexpected to be smaller than its presently measured size. Given the youth of thisstarandofthenewplanet,the favorable geometry of thedisc and the relative proximity to the Earth, the authors suggest that this system could be useful for the study of the early stages of the formation of planets. The researcher Enric Pallé explains that: “This planet can help us to understand the first stages of the evolution of planetary atmos- pheres, because it is during the first years of formation when a major part (or even all) of these atmos- pherescanbelostintospace,dueto interaction with the host star. This determines the type of planetswhich we find after these first for- mationphases.”  ﻣﺠﻠﺔ FreeAstronomy ﺎﻟﻌﺮ ﺔ 41 ﺗﻤﺜﻴــــــــﻞ ﻟﻲ ﻠـــــــــ ﺨﺗ ﻠﻨﻈـــــــــﺎم IRAS04125+2902 ـــﻮن ﺣــﺪ ﺚ اﻟﺘ ] NASA/JPL- Caltech/R.Hurt, K.Miller (Caltech/IPAC [( اﻟﻜﻮﻛﺒﻲ اﻟﺨﺎرﺟﻲ اﻷوﱄ ا ﺤﻴﻂ ﺑﻬﺬا اﻟﻨﺠﻢ ﻘﺎ ﻏ ﻣ ﺑﻞ ﻟﻸرض ﺑﺎﻟﺪرﺟﺔ ا ﻨﺎﺳﺒﺔ ﻟ ﻪ ﺮؤﻳﺘ ﺑﺪﻻً ﻣﻦ اﻟ اﻷ ﻮﺿﻊ ﻛﺜـﺮ ﺷـﻴﻮﻋﺎً إﺣﺼـﺎﺋﻴ ﺎً ﺑﺎﻹﺿﺎﻓﺔ إﱃ ذﻟﻚ اﻛﺘﺸـﻔﻮا ﻗﺮﺻـﺎ داﺧﻠﻴـ ﺎً ﺎً ﺿﻌﻴﻔ ﻟﻠﻐﺎﻳﺔ . ﻟﻘﺪ ﺳﻤﺢ ﻟﻬﻢ ﻫﺬا ا ﺰﻳﺞ اﻟﻘﻴـﺎم ﺑﻤﺮاﻗﺒـﺔ اﻟﻜﻮﻛﺐ اﻷوﱄ اﻟﻌﺎﺑﺮ IRAS 04125+2902 b . أﻇﻬﺮت اﻟﺪراﺳﺔ أن ﻫﺬا اﻟﻜﻮﻛﺐ ﻟﻪ ﻓﱰة ﻣﺪارﻳﺔ ﺗﺒﻠﻎ 8.83 ﻳﻮﻣﺎً وﻧﺼﻒ ﻗﻄﺮه أﻛـﱪ ﺑﻤﻘﺪار 10.7 ﻣﺮة ﻣﻦ ﻧﺼـﻒ ﻗﻄـﺮ اﻷرض ـــ و ﻳﺸﻜﻞ ﻛﺘﻠﺔ ﺗﻌﺎدل ﺣﻮاﱄ 30 % ﻣـﻦ ﻛﺘﻠـﺔ ا ﺸﱰي . ﻳﻘﱰح ﻣﺆﻟﻔﻮ ا ﻘﺎل أن اﻟﻜﻮﻛﺐ أو اﻟﻜﻮﻛﺐ اﻷوﱄ ﻗﺪ ﻳﻜﻮن ﺳﻠﻔًﺎ ﻟـ ﻟـﻸراﴈ " اﻟﻔﺎﺋﻘﺔ دون " أو " ﻧﺒﺘﻮن " واﻟﺘﻲ ﻏﺎﻟﺒ ﺎً ﻣـﺎ ﺗﻮﺟﺪ ﺣﻮل ﻧﺠﻮم اﻟﺘﺴﻠﺴﻞ اﻟﺮﺋﻴ ﴘـ وﻫﻲ ﺗﻠﻚ اﻟﺘﻲ ﺗﺤﺮق اﻟﻬﻴﺪروﺟ . ﻳﺴﺘﻨﺘﺞ اﻟﺒﺎﺣﺜﻮن ذﻟﻚ ﻷن اﻟﻜﻮﻛﺐ ﻻ ﻳـﺰال ﰲ ﻃﻮر اﻻﻧﻜﻤﺎش وﻣﻦ ا ﺘﻮﻗـﻊ أن ﻳﻜـﻮن ﺣﺠﻤﻪ ا ﻟﻨﻬﺎﺋﻲ ﰲ ﻧﻬﺎﻳﺔ ا ﻄﺎف أﺻﻐﺮ ﻣـﻦ ﺣﺠﻤﻪ ا ﻘﺎسﺣﺎﻟﻴ .ﺎً ﻧﻈـﺮاً ﻻن ﻫ ـﺬا اﻟــﻨﺠﻢ ﺣـﺪﻳﺚ اﻟﺘﻜ ـﻮﻳﻦ و اﻟﻜﻮﻛﺐ اﻟﺠﺪﻳﺪ واﻟﻬﻨﺪﺳﺔ ا ﻼﺋﻤ ﺔ ﻟﻠﻘﺮص واﻟﻘﺮب اﻟﻨﺴﺒﻲ ﻣﻦ اﻷرض ﻳﻘﱰح ا ﺆ ﻟﻔﻮن ﻟﻬﺬه اﻟﺪراﺳﺔ ﺑ ﺄن ﻫﺬا اﻟﻨﻈـﺎم ﻗـﺪ ﻳﻜـﻮن اً ﻣﻔﻴﺪ ﺟﺪاً ﻟﺪراﺳـﺔ ا ﺮاﺣـﻞ ا ﺒﻜـﺮة ﻣـﻦ ﺗﻜﻮﻳﻦ اﻟﻜﻮاﻛﺐ . ﻳﻮﺿـﺢ اﻟﺒﺎﺣـﺚ إﻧﺮﻳــﻚ ﺑﺎﻟﻴــﻪ " : إن ﻫـﺬا اﻟﻜﻮﻛﺐ ﻳ أن ﻳﻤﻜﻦ ﺴﺎﻋﺪﻧﺎ ﰲ ﻓﻬﻢ ا ﺮاﺣـﻞ اﻷو ﱃ ﻣﻦ ﺗﻄﻮر اﻟﻐـﻼف اﻟﺠـﻮي ﻟﻠﻜﻮاﻛـﺐ ﻷﻧﻪ وذﻟﻚ ﺧﻼل اﻟﺴﻨﻮات اﻷوﱃ ﻣﻦ اﻟﺘﻜﻮﻳﻦ ﻳﻤﻜﻦ ﻟﺠﺰء ﻛﺒ ) أو ﺣﺘﻰ ﻛﻞ ( ﻏﻠﻔﺔ ﻫﺬه اﻷ اﻟﺠﻮﻳﺔ أن ﺗﺘﻼﳽﰲ اﻟﻔﻀﺎء ﺑﺴﺒﺐ اﻟﺘﻔﺎﻋﻞ ﻣﻊ اﻟﻨﺠﻢ ا ﻀﻴﻒ . ﺗﺴﺎﻋﺪﻧﺎ اﻟﺒﻴﺎﻧﺎت ا ﺘﺤﺼﻠﺔ ﻣﻦ دراﺳﺔ ﻫﺬا اﻟﻜﻮﻛﺐ ﺗﺤﺪﻳﺪ ﻧﻮع اﻟﻜﻮاﻛﺐ اﻟﺘـﻲ ﻧﺠـﺪﻫﺎ ﺑﻌﺪ ﻣﺮاﺣﻞ اﻟﺘﻜﻮﻳﻦ اﻷوﱃ ﻫﺬه .

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