Free Astronomy Magazine July-August 2023 ARABIC VERSION

subtends an angle of 40-50 milliarc- seconds, the complex variability of this star makes it impossible to calcu- late precisely the distance and a whole series of physical properties (absolute luminosity, radius, current mass, initial mass, internal rotational state and associated composition). If these properties were known, we could precisely match observations, data and models, defining the cur- rent evolutionary stage of Betel- geuse and therefore the expected times for the final event. Since it is not possible to unequivocally charac- terize the star, the models provide several possible scenarios, with the result that no researcher knows ex- actly what type of reaction is cur- rently taking place in the nucleus of Betelgeuse. The only certainty is that the phase of fusion of hydro- gen into helium ended some time ago and that the phase of helium into carbon began after the con- traction of the nucleus that, follow- ing the depletion of hydrogen, raised the star’s temperature (with consequent expansion of the outer layers of the star). However, it is far from certain whether the fusion of helium into carbon inside the nu- cleus is still ongoing, or if the he- lium has also run out and conditions have been reached to trigger the fusion of carbon into heavier ele- ments following a further contrac- tion. Unfortunately, direct observa- tion of Betelgeuse does not high- light anything that happens in the depths because, contrary to what happens in Sun-like stars, the outer layers of the red supergiants are not ﻳﻮﻟﻴﻮ - ﺃﻏﺴﻄﺲ 2 0 2 3 7 ﻣﺠﻠﺔ FreeAstronomy ﺎﻟﻌﺮ ﺔ ﺻـــــــــﻮرة ﺎﻷﺷـــــــــﻌﺔ ﻓـــــــــﻮق اﻟ ﻨﻔﺴـــــــــﺠ ﺔ ﻟﻤﻨﻜـــــــــﺐ ـ اﻟـــــــ ﺠﻮزاء ﻣــــــــﺄﺧﻮذة ﺑﻮاﺳــــــــﻄﺔ ﺗﻠﺴــــــــ ﻮبﻫﺎﺑــــــــﻞ اﻟﻔﻀــﺎﺋﻲ . ﻳﺠـــﺐ أن ــﻮن اﻟ ﻘﻌـــﺔ اﻟﻤﻀــﻴﺌﺔ ﻓـــﻲ ﺗ اﻟﺼــﻮرة أﺣــﺪ ﻣــﺎ ﺴـــﻤﻰ ﺎﻟﻨﻘــﺎط اﻟﺴــﺎﺧﻨﺔ أﺣـــﺪ أﻗﻄﺎب اﻟﻨ ﻢ ] . ﻧﺎﺳﺎ / و ﺎﻟﺔ اﻟﻔﻀﺎء اﻷوروﺑ ﺔ [ ﻟﺴﻮء اﻟﺤﻆ ﻋﲆ اﻟﺮﻏﻢ ﻣﻦ أن ﻣﻨﻜﺐ اﻟﺠﻮزاء ﻳﻘﺎﺑﻞ زاوﻳﺔ 40 - 50 ﺛﺎﻧﻴﺔ ﻣﲇ ﻓﺈن اﻟﺘﺒـﺎﻳﻦ ا ﻌﻘﺪ ﻟﻬـﺬا اﻟـﻨﺠﻢ ﻳﺠﻌـﻞ ﻣـﻦ ا ﺴـﺘﺤﻴﻞ ﺣﺴــﺎب ا ﺴــﺎﻓﺔ وﺳﻠﺴــﻠﺔ ﻛﺎﻣﻠــﺔ ﻣــﻦ اﻟﺨﺼﺎﺋﺺ اﻟﻔﻴﺰﻳﺎﺋﻴﺔ ﺑﺪﻗﺔ ) اﻟﻠﻤﻌﺎن ا ﻄﻠ ﻖ ، ﻧﺼﻒ اﻟﻘﻄـﺮ ، اﻟﻜﺘﻠـﺔ اﻟﺤﺎﻟﻴـﺔ ، اﻟﻜﺘﻠـﺔ اﻷوﻟﻴﺔ ، ﺣﺎﻟﺔ اﻟﺪوران اﻟﺪاﺧﲇ واﻟﺘﻜـﻮﻳﻦ إذا ﻛﺎﻧﺖ ﻫـﺬه اﻟﺨﺼـﺎﺋﺺ ﻣﻌﺮوﻓـﺔ ﻓﻴﻤﻜﻨﻨـﺎ ﻣﻄﺎﺑﻘﺔ اﻷرﺻﺎد واﻟﺒﻴﺎﻧﺎت واﻟﻨﻤـﺎذج ﺑﺪﻗـﺔ وﺗﺤﺪﻳﺪ ا ﺮﺣﻠﺔ اﻟﺘﻄﻮرﻳﺔ اﻟﺤﺎﻟﻴﺔ ﻣﻦ ﻣﻨﻜﺐ اﻟﺠﻮزاء وﺑﺎﻟﺘﺎﱄ اﻷوﻗـﺎت ا ﺘﻮﻗﻌـﺔ ﻟﻠﺤـﺪث اﻟﻨﻬﺎﺋﻲ . ﻧﻈﺮًا ﻷﻧﻪ ﻻ ﻳ ﻤﻜـﻦ وﺻـﻒ اﻟـﻨﺠﻢ ﺑﺸﻜﻞ ﻻ ﻟﺒﺲ ﻓﻴﻪ ﻓﺈن اﻟﻨﻤﺎذج ﺗﻘﺪم اﻟ ﻌﺪﻳﺪ ﻣﻦ اﻟﺴﻴﻨﺎرﻳﻮﻫﺎت ا ﺤﺘﻤﻠﺔ وﻧﺘﻴﺠﺔ ﻟـﺬﻟﻚ ﻻ ﻳﻌﺮف أي ﺑﺎﺣﺚ ﺑﺎﻟﻀﺒﻂ ﻧﻮع اﻟﺘﻔﺎﻋﻞ اﻟـﺬي ﻳﺤﺪث ﺣﺎﻟﻴًﺎ ﰲ ﻧﻮاة ﻣﻨﻜﺐ اﻟﺠﻮزاء . اﻟﻴﻘـ اﻟﻮﺣﻴﺪ ﻫﻮ أن ﻣﺮﺣﻠﺔ اﻧﺪﻣﺎج اﻟﻬﻴﺪروﺟ ﰲ اﻟﻬﻴﻠﻴﻮم اﻧﺘﻬﺖ ﻣﻨﺬ ﺑﻌﺾ اﻟﻮﻗﺖ وأن ﻣﺮﺣﻠﺔ اﻟ ﻬﻴﻠﻴﻮم إﱃ اﻟﻜﺮﺑﻮن ﺑﺪأت ﺑﻌﺪ ﺗﻘﻠﺺ اﻟﻨﻮاة اﻟﺘﻲ أدت ﺑﻌﺪ اﺳﺘﻨﻔﺎد ذﻟـﻚ اﻟﻬﻴـﺪروﺟ إﱃ رﻓﻊ درﺟﺔ ﺣﺮارة اﻟﻨﺠﻢ ) ﻣﻊ ﻣﺎ ﻳﱰﺗﺐ ﻋـﲆ ذﻟﻚ ﻣﻦ ﺗﻮﺳﻊ ( اﻟﻄﺒﻘﺎت اﻟﺨﺎرﺟﻴﺔ ﻟﻠﻨﺠﻢ ( وﻣﻊ ذﻟﻚ ﻓﻠـﻴﺲ ﻣـﻦ ا ﺆﻛـﺪ ﻣـﺎ إذا ﻛـﺎن اﻧﺪﻣﺎج اﻟﻬﻴﻠﻴﻮم ﰲ اﻟﻜﺮﺑـﻮن داﺧـﻞ اﻟﻨـﻮاة ﻻ ﻳﺰال ﻣﺴﺘﻤﺮاً أو إذا ﻧﻔﺪ اﻟﻬﻴﻠﻴـﻮم أﻳﻀًـﺎ وﺗﻢ اﻟﻮﺻﻮل إﱃ ﻇـﺮوف ﻟ ﺘﺤﻔﻴـﺰ اﻧـﺪﻣﺎج اﻟﻜﺮﺑﻮن ﰲ ﻋﻨﺎﴏ أﺛﻘـﻞ ﺑﻌـﺪ ﻣﺰﻳـﺪ ﻣـﻦ اﻻﻧﻜﻤ ـﺎش . ﻟﺴـﻮء اﻟﺤـﻆ، ﻓــﺈن اﻟﺮﺻـﺪ ا ﺒﺎﴍة ﻨﻜﺐ اﻟﺠﻮزاء ﻻ ﻳﺴﻠﻂ اﻟﻀﻮء ﻋﲆ أي ﳾء ﻳﺤﺪث ﰲ اﻷﻋﻤﺎق ﻷﻧﻪ ﻋﲆ ﻋﻜـﺲ ﻣﺎ ﻳﺤﺪث ﰲ اﻟﻨﺠﻮم اﻟﺸﺒﻴﻬﺔ ﺑﺎﻟﺸﻤﺲ ﻓﺈن اﻟﻄﺒﻘ ـﺎت اﻟﺨﺎرﺟﻴ ـﺔ ﻟﻠﻨﺠــﻮم اﻟﻌﻤﻼﻗ ـﺔ اﻟﺤﻤــﺮاء ﻟﻴﺴـــﺖ ذات ﺣﻤـــﻞ ﺣــﺮاري ــــ ـــــ ـــﻢ ﻣـــﺎ ﻫـــﻮ ﺣ اﻟـــﻨ ﻢ ـ ﻣﻨﻜـــﺐ اﻟـــ ﺠﻮزاء ﻣﻘﺎر ـــﺔ ــــــــــﺪﻳﻮ ـــــــــﺎﻟﻨﺠﻮم اﻷﺧـــــــــﺮى؟ ُﻈﻬـــــــــﺮﻫـــــــــﺬا اﻟﻔ ﻣﻘﺎﻳ ﺲ اﻟﻨﺠﻮم اﻟﻤﻌﺮوﻓﺔ ﻓﻲﻣﺠﺮﻨـﺎ در ﺿــــــﺨﺎﻣ اﻟﺘ ﺎﻧــــــﺔ و ﻈﻬــــــﺮ ﻟــــــﻚ ﻣــــــﺪ ﺔ ﻣﻨﻜــــــﺐ ـ اﻟــــــــ ﺠﻮزاء ﺣﻘًــــــــﺎ . ــــــــﺪﻳﻮ ﺗــــــــﻢ اﻟﺘﻘــــــــﺎطﻫــــــــﺬا اﻟﻔ اﻟﻘﺼ ﻣﻦ ﻋﺮض اﻟﻘ ﺔ اﻟﺴـﻤﺎو ﺔ اﻟﺸـﻤﺲ ﻧ ﻤﻨﺎ اﻟـﺤﻲ . ] ESO/L. Calçada/M. Kornmesser [