Free Astronomy Magazine September-October 2023 ARABIC VERSION

inner disk of PDS 70. However, they do see the raw materials for build- ing rocky worlds in the form of sili- cates. The detection of water vapor implies that if rocky planets are forming there, they will have water available to them from the begin- ning. “We find a relatively high amount of small dust grains. Com- bined with our detection of water vapor, the inner disk is a very excit- ing place,” said co-author Rens Wa- ters of Radboud University in The Netherlands. The discovery raises the question of where the water came from. The MINDS team considered two differ- ent scenarios to explain their find- ing. One possibility is that water molecules are forming in place, where we detect them, as hydrogen and oxygen atoms combine. A sec- ond possibility is that ice-coated dust particles are being transported from the cool outer disk to the hot inner disk, where the water ice sub- limates and turns into vapor. Such a transport system would be surpris- ing, since the dust would have to cross the large gap carved out by the two giant planets. Another question raised by the dis- covery is how water could survive so close to the star, when the star’s ul- traviolet light should break apart any water molecules. Most likely, surrounding material such as dust and other water molecules serves as a protective shield. As a result, the water detected in the inner disk of PDS 70 could survive destruction. Ultimately, the team will use two more of Webb’s instruments, NIR- Cam (Near-Infrared Camera) and NIRSpec (Near-Infrared Spectro- graph) to study the PDS 70 system in an effort to glean an even greater understanding.     ﻣﺠﻠﺔ FreeAstronomy ﺎﻟﻌﺮ ﺔ 30 اﻟﺴﺎﺑﻘﺔ ﻓﺸﻠﺖ ﰲ اﻛﺘﺸﺎف ا ﺎء ﰲ ا ﻨـﺎﻃﻖ ا ﺮﻛﺰﻳﺔ ﻟﻸﻗﺮاص ذات اﻟﻌﻤﺮ ا ﻤﺎﺛـﻞ ﻓﻘـﺪ اﺷﺘﺒﻪ ﻋﻠﻤﺎء اﻟﻔﻠﻚ ﰲ أﻧﻬﺎ ﻗﺪ ﻻ ﺗﻨﺠـﻮ ﻣـﻦ اﻹﺷﻌﺎع اﻟﻨﺠﻤﻲ اﻟﻘﺎﳼ ﻣﻤﺎ ﻳﺆدي إﱃ ﺑﻴﺌﺔ ﺟﺎﻓﺔ ﻟﺘﺸـﻜﻴﻞ أي ﻛﻮاﻛـﺐ ﺻـﺨﺮﻳﺔ . ﻟـﻢ ﻳﻜﺘﺸ ـﻒ اﻟ ﻌﻠﻤ ـﺎء ﺣﺘــﻰ اﻵن أي ﻛﻮاﻛــﺐ ﺗﺘﺸﻜﻞ ﰲ اﻟﻘﺮص اﻟﺪاﺧﲇ ﻟﻠﻨﺠﻢ PDS 70 . وﻣﻊ ذﻟﻚ ﻓﻬﻢ ﻳﺮون ا ﻮاد اﻟﺨﺎم ﻟﺒ ﻨﺎء ﻋﻮاﻟﻢ ﺻـﺨﺮﻳﺔ ﻋـﲆ ﺷـﻜﻞ ﺳـﻴﻠﻴﻜﺎت وﻳﺸــ اﻛﺘﺸﺎف ﺑﺨﺎر ا ﺎء إﱃ أﻧﻪ إذا ﻛ ﺎﻧﺖ اﻟﻜﻮاﻛﺐ اﻟﺼﺨﺮﻳﺔ ﺗﺘﺸﻜﻞ ﻫﻨﺎك ﻓﺴﻴﻜﻮن ﻟﺪﻳﻬﺎ ﻣﺎء ﻣﺘﺎح ﻟﻬﺎ ﻣﻨﺬ اﻟﺒﺪاﻳﺔ " . ﻟﻘـﺪ وﺟـﺪﻧﺎ ﻛﻤﻴـﺔ ﻣﺘﺎح ﻟﻬﺎ ﻣﻨﺬ اﻟﺒﺪاﻳﺔ . ﻗﺎل ا ﺆﻟـﻒ ا ﺸـﺎرك رﻳﻨﺲ ووﺗﺮز ﻣﻦ ﺟﺎﻣﻌﺔ رادﺑﻮد ﰲ ﻫﻮﻟﻨﺪا : " ﻟﻘﺪ وﺟﺪﻧﺎ ﻛﻤﻴﺔ ﻛﺒ ة ﻧﺴﺒﻴ ﺎً ﻣﻦ ﺣﺒﻴﺒﺎت اﻟﻐﺒﺎر اﻟﺼﻐ ة وﻣﻊ اﻛﺘﺸﺎﻓﻨﺎ ﻟﺒﺨﺎر ا ـﺎء ﻳﺼﺒﺢ اﻟﻘﺮص اﻟﺪاﺧﲇ ﻣﻜﺎﻧ ﺎُ اً ﻣﺜ ﻟﻠﻐﺎﻳﺔ « وﻳﺜـ ﻫـﺬا اﻻﻛﺘﺸــﺎف اﻟﺘﺴـﺎؤﻻت ﺣـﻮل ﻣﺼﺪر ا ﻴﺎه . ﻧﻈﺮ ﻓﺮﻳﻖ ﺑﺮﻧﺎﻣﺞ ) ( ﻣﺎﻳﻨـﺪز ﰲ ﺳﻴﻨﺎرﻳﻮﻫ ﻣﺨﺘﻠﻔ ﻟـ ـ ﴩح اﻟﻨﺘـﺎﺋﺞ اﻟﺘﻲ ﺗﻮﺻﻠﻮا إﻟﻴﻬﺎ أﺣﺪ اﻻﺣﺘﻤـﺎﻟ أن ﻫـﻮ ﺟﺰﻳﺌـﺎت ا ــﺎء ﺗﺘﺸـﻜﻞ ﰲ ﻣﻜﺎﻧﻬـﺎ ﺣﻴـﺚ ﻧﻜﺘﺸﻔﻬﺎ ﻋﻨﺪﻣﺎ ﺗﺘﺤـﺪ ذرات اﻟﻬﻴـﺪروﺟ واﻷﻛﺴﺠ . واﻷﻛﺴــﺠ واﻻﺣﺘﻤــﺎل اﻟﺜــﺎﻧﻲ ﻫــﻮ أن ﺟﺰﻳﺌﺎت اﻟﻐﺒﺎر ا ﻐﻄﺎة ﺑﺎﻟﺠﻠﻴﺪ ﻳـﺘﻢ ﻧﻘﻠﻬـﺎ ﻣﻦ اﻟﻘﺮص اﻟﺨـﺎرﺟﻲ اﻟﺒـﺎرد إﱃ اﻟﻘـﺮص اﻟﺪاﺧﲇ اﻟﺴﺎﺧﻦ ﺣﻴﺚ ﻳﺘ ﺼﺎﻋﺪ ﺟﻠﻴـﺪ ا ـﺎء وﻳﺘﺤﻮل إﱃ ﺑﺨﺎ ر ﺳﻴﻜﻮن ﻧﻈﺎم اﻟﻨﻘﻞ ﻫـﺬا ﻣﻔﺎﺟﺌﺎً ﺣﻴﺚ ﺳﻴﺘﻌ ﻋـﲆ اﻟﻐﺒـﺎر ﻋﺒـﻮر اﻟﻔﺠﻮة اﻟﻜﺒـ ة اﻟﺘـﻲ ﺣﻔﺮﻫـﺎ اﻟﻜﻮﻛﺒـﺎن اﻟﻌﻤﻼﻗﺎن . ﺳﺆال آﺧﺮ ﻳﺜ ه ﻫﺬا اﻻﻛﺘﺸـﺎف ﻫﻮ ﻛﻴﻒ ﻳﻤﻜﻦ ﻟﻠﻤﻴﺎه اﻟﺒﻘﺎء ﻗﺮب اﻟﻨﺠﻢ ﰲ ﺣ أن ﺿﻮء اﻟﻨﺠﻢ ﻓﻮق اﻟﺒﻨﻔﺴﺠﻲ ﻳﺠـﺐ أن ﻳﻜﴪ أي ﺟﺰﻳﺌـﺎت ﻣـﺎء ﻓ ﻌـﲆ اﻷرﺟـﺢ ﺗﻌﻤﻞ ا ﻮاد ا ﺤﻴﻄﺔ ﻣﺜﻞ اﻟﻐﺒﺎر وﺟﺰﻳﺌـﺎت ا ﺎء اﻷ ﺧﺮى ﻛـﺪرع ﺣﻤﺎﻳـﺔ وﻧﺘﻴﺠـﺔ ﻟـﺬﻟﻚ ﻳﻤﻜﻦ ﻟﻠﻤﻴﺎه ا ﻜﺘﺸﻔﺔ ﰲ اﻟﻘﺮص اﻟـﺪاﺧﲇ ﻟﻠﻨﺠﻢ PDS 70 اﻟﻨﺠﺎة ﻣﻦ اﻟﺘﺪﻣ . - ﺳﺒﺘﻤﺒﺮ ﺃﻛﺘﻮﺑﺮ 2 0 2 3 اﻷوﻟـــﻲ ﻟــــ ــــﻮﻛ ـــﻒ اﻟﻘـــﺮص اﻟ ﻌـــﺮضﻃ PDS 7 ﺗـــﻢ اﻟـــ اﻟــــﺬ ـ ــــﮫ ﺎﺳـــﺘﺨﺪام ﺤﺼﻮل ﻋﻠ ـــﺎﻣ ا ﻣــــ ي ـــﺐ ﻟﺘﻠﺴـــ ﻮب و ) أداة اﻷﺷـــﻌﺔ ﺗﺤـــﺖ اﻟـــ ـ ﻤﺮاء اﻟﻤﺘﻮﺳـــﻄﺔ اً ﻋـــﺪد ( ﻣـــﻦ ﺧﻄـــﻮط اﻻﻧ ﻌـــﺎث ﻣـــﻦ ﺑﺨـــﺎراﻟﻤـــﺎء وﺗﻮﺻﻞ اﻟﻌﻠﻤﺎء إﻟﻰ أن اﻟﻤﺎ ء ﻣﻮﺟﻮد ﻓﻲ اﻟﻘﺮص اﻟﺪاﺧﻠﻲ ﻟﻠﻨﻈـﺎم ﻋﻠـﻰﻣﺴـﺎﻓﺔ ﺗﻘـﻞ ﻋـﻦ 100 ﻣﻠﻴـﻮن ﻣﻴــﻞ ﻣــﻦ اﻟــﻨ ﻢ ﻗــﺪ ﺗﺘﺸــ ﻞ ﻓﻴﻬــﺎ اﻟ ﻮاﻛــﺐ اﻟﺼــﺨﺮ ﺔ وﻫــﻲ اﻟﻤﻨﻄﻘــﺔ اﻟــ . ] NASA, ESA, CSA, Joseph Olmsted(STScI [(