Free Astronomy Magazine January-February 2023 ARABIC VERSION

ous attempts — as well as those of others — turned up a menagerie of binary systems that masquerade as black holes, but this is the first time the search has borne fruit.” The team originally identified the system as potentially hosting a black hole by analyzing data from the Eu- ropean Space Agency’s Gaia space- craft. Gaia captured the minute irregularities in the star’s motion caused by the gravity of an unseen massive object. To ex- plore the system in more detail, El-Badry and his team turned to the Gemini Multi-Ob- ject Spectrograph in- strument on Gemini North, which meas- ured the velocity of the companion star as it orbited the black hole and provided pre- cise measurement of its orbital period. The Gemini follow-up ob- servations were crucial to constraining the or- bital motion and hence masses of the two components in the binary system, allow- ing the team to iden- tify the central body as a black hole roughly 10 times as massive as our Sun. “Our Gemini fol- low-up observations confirmed be- yond reasonable doubt that the binary contains a normal star and at least one dormant black hole,” elab- orated El-Badry. “We could find no plausible astrophysical scenario that can explain the observed orbit of the system that doesn’t involve at least one black hole.” The team re- lied not only on Gemini North’s su- perb observational capabilities but also on Gemini’s ability to provide data on a tight deadline, as the team had only a short window in which to perform their follow-up observations. “When we had the first indications that the system con- tained a black hole, we only had one week before the two objects were at the closest separation in their orbits. Measurements at this point are es- sential to make accurate mass esti- mates in a binary system,” said El- Badry. “Gemini’s ability to provide observations on a short timescale was critical to the project’s success. If we’d missed that narrow window, we would have had to wait another year.” Astronomers’ current models of the evolution of binary systems are hard-pressed to explain how the peculiar configuration of Gaia BH1 system could have arisen. Specifi- cally, the progenitor star that later turned into the newly detected black hole would have been at least 20 times as massive as our Sun. This means it would have lived only a few million years. If both stars formed at the same time, this mas- sive star would have quickly turned into a supergiant, puffing up and engulfing the other star before it had time to become a proper, hydro- gen-burning, main-sequence star like our Sun. It is not at all clear how the solar- mass star could have survived that episode, ending up as an apparently normal star, as the observations of the black hole binary indicate. The- oretical models that do allow for survival all predict that the solar- mass star should have ended up on a much tighter orbit than what is ac- tually observed. This could indicate that there are important gaps in our under- standing of how black holes form and evolve in binary systems, and also suggests the exis- tence of an as-yet-un- explored population of dormant black holes in binaries. “It is interest- ing that this system is not easily accommo- dated by standard bi- nary evolution models,” concluded El-Badry. “It poses many questions about how this binary system was formed, as well as how many of these dormant black holes there are out there.” “As part of a network of space- and ground-based observatories, Gemini North has not only provided strong evidence for the nearest black hole to date but also the first pristine black hole system, uncluttered by the usual hot gas interacting with the black hole,” said NSF Gemini Program Officer Martin Still. “While this potentially augurs future dis- coveries of the predicted dormant black hole population in our Galaxy, the observations also leave a mys- tery to be solved — despite a shared history with its exotic neighbor, why is the companion star in this binary system so normal?”     summarizes the discovery of the closest black hole to J.Pollard/J. da Silva/Spaceengine/ M. Zamani/ T. Müller (MPIA), Pan- STARRS DR1 (K. C. Chambers et al. 2016), ESA/Gaia/DPAC (CC BY-SA 3.0 IGO)/ NASA’s Scientific Visualization Studio/ Walt Feimer (HTSI)/ Michael McClare (HTSI)/Dana Berry (Skyworks Digital)/ Michael Mc- Clare (HTSI), N. Bartmann] ﻣﺠﻠﺔ Astronomy ﺎﻟﻌﺮ ﺔ ٤٢ ﻟﻘـﺪ أﻇﻬـﺮت ﻣﺤـﺎوﻻﺗﻲ اﻟﺴـﺎﺑﻘﺔ وﻛـﺬﻟﻚ ﻣﺤﺎوﻻت اﻵ ﺧـﺮﻳﻦ ﻣﺠﻤﻮﻋـﺔ ﻣـﻦ اﻷﻧﻈﻤـﺔ اﻟﺜﻨﺎﺋﻴﺔ اﻟﺘﻲ ﺗﺘﻨﻜﺮ ﰲ ﺷـﻜﻞ ﺛﻘـﻮب ﺳـﻮداء وﻟﻜﻦ ﻫﺬه ﻫﻲ ا ﺮة اﻷوﱃ اﻟﺘـﻲ ﻳـﺆﺗﻲ ﻓﻴﻬـﺎ اﻟﺒﺤﺚ ﺛﻤﺎره . ﺣﺪد اﻟﻔﺮﻳﻖ ﰲ اﻷﺻﻞ اﻟﻨﻈـﺎم ﻋﲆ أﻧﻪ ﻳﺤﺘﻤﻞ أن ﻳﺴﺘﻀﻴﻒ ﺛﻘﺒًﺎ أﺳﻮد ﻣـﻦ ﺧﻼل ﺗﺤﻠﻴﻞ اﻟﺒﻴﺎﻧﺎت ﻣﻦ ﻣﺮﻛﺒﺔ اﻟﻔﻀﺎء ﺎﻳﺎ ﻏ ا ﻟﺘﺎﺑﻌﺔ ﻟﻮﻛﺎﻟﺔ اﻟﻔﻀﺎء اﻷوروﺑﻴـﺔ ﺣﻴـﺚ ﺗـﻢ اﻟﺘﻘﺎط وﺗﺴﺠﻴﻞ اﺧﺘﻼﻻت ﻏ اﻋﺘﻴﺎدﻳﺔ ﰲ ﺣﺮﻛﺔ اﻟﻨﺠﻢ اﻟﻨﺎﺗﺠﺔ ﻋﻦ ﺟﺎذﺑﻴﺔ ﺟﺴـﻢ ﻫﺎﺋـﻞ ﻏـ ﻻ . ﻣﺮﺋﻲ ﺳﺘﻜﺸﺎف اﻟﻨﻈـﺎم ﺑﻤﺰﻳﺪ ﻣـﻦ اﻟﺘﻔﺼـﻴﻞ ، ﻟﺠـﺄ اﻟﺒـﺪرى وﻓﺮﻳﻘـﻪ إﱃ ﺟﻬـﺎز ﻣﻘﻴ ـﺎسﺟﻴﻤ ـﻲ اﻟﻄﻴﻔ ـﻲ ﻟﻸﺟﺮام ا ﺘﻌﺪدة ا ﺜﺒﺖ ﻋﲆ ﺗﻠﺴــﻜﻮب ﺟﻴﻤﻨ ـﻲ ﻧ ـﻮرث واﻟﺬي ﻗﺎس ﴎﻋـﺔ اﻟـﻨﺠﻢ ا ﺮاﻓﻖ أﺛﻨﺎء دوراﻧـﻪ ﺣـﻮل اﻟﺜﻘﺐ اﻷﺳﻮد وﻗﺪم ﻗﻴﺎﺳًـﺎ دﻗﻴﻘًﺎ ﻟﻔـﱰة ﻣـﺪاره . ﻟﻘـﺪ ﻛﺎﻧﺖ أرﺻﺎد ﻣﺮﺻﺪ ﺟﻴﻤﻨﻲ اﻟﻼﺣﻘﺔ ﺣﺎﺳـﻤﺔ ﰲ ﺗﻘﻴﻴـﺪ اﻟﺤﺮﻛﺔ ا ﺪارﻳﺔ وﺑﺎﻟﺘﺎﱄ ﻛﺘﻞ ا ﻜﻮﻧ ﰲ اﻟﻨﻈـﺎم اﻟﺜﻨـﺎﺋﻲ ا ﻣﻜﻦ ﻣﻤﺎ ﻟﻔﺮﻳﻖ ﻣﻦ ﺗﺤﺪﻳﺪ اﻟﺠﺴﻢ ا ﺮﻛﺰي ﻋﲆ أﻧـﻪ ﺛﻘـﺐ أﺳـﻮد ﻳﺒﻠـﻎ ﺣﺠﻤـﻪ ﺣـﻮاﱄ ١٠ أﺿـﻌﺎف ﻛﺘﻠـﺔ اﻟﺸـﻤﺲ وأوﺿﺢ اﻟﺒﺪري أن ، اﻷرﺻـﺎد ﺘا ﺘﺎﺑﻌـﺔ اﻟﺘـﻲ أﺟﺮﻳﻨﺎﻫﺎ ﰲ ﻣﺮﺻﺪ ﺟﻴﻤﻴﻨﻲ أﻛﺪت ﺑﻤﺎ ﻻ ﻳـﺪع ﻣﺠﺎﻻً ﻟﻠﺸﻚ ﰲ أن اﻟﺜﻨﺎﺋﻲ ﻳﺤﺘﻮي ﻋـﲆ ﻧﺠـﻢ ﻋﺎدي وﺛﻘﺐ أﺳﻮد ﺧﺎﻣﺪ واﺣﺪ ﻋﲆ اﻷﻗﻞ ﻟﻢ ". ﻧﺘﻤﻜﻦ ﻣﻦ اﻟﻌﺜـﻮر ﻋـﲆ ﺳـﻴﻨﺎرﻳﻮ ﻓﻴﺰﻳـﺎﺋﻲ ﻓﻠﻜﻲ ﻣﻌﻘﻮل ﻳﻤﻜﻦ أن ﻳﻔﴪ ا ﺪار ا ﺮﺻـﻮد ﻟﻠﻨﻈﺎم اﻟﺬي ﻻ ﻳﺘﻀﻤﻦ ﺛﻘﺒًﺎ أﺳﻮد واﺣﺪًا ﻋﲆ اﻷﻗﻞ ". ﻟﻢ ﻳﻜﺘﻒ اﻟﻔﺮﻳﻖ ﺑﺎﻟﺮد ﻋﲆ إﻣﻜﺎﻧﻴـﺎت ا ﻟﺮﺻﺪ اﻟﺮاﺋﻌﺔ ﻟﺠﻴﻤﻴﻨﻲ ﻧـﻮرث ﻓﺤﺴـﺐ ﺑـﻞ أﻳﻀًﺎ ﻋﲆ ﻗﺪرة ﺟﻴﻤﻴﻨﻲ ﻋﲆ ﺗﻮﻓ اﻟﺒﻴﺎﻧﺎت ﰲ ﻣﻮﻋﺪ ﻧﻬﺎﺋﻲ ﺿـﻴﻖ ، ﺣﻴـﺚ ﻟـﻢ ﻳﻜـﻦ أﻣـﺎم ــــــ اﻟﻔﺮﻳﻖ ﺳﻮى ﻓﱰة ﻗﺼ ة ﻹﺟﺮاء . اﻟﻔﺮﻳﻖ ﺳﻮى ﻓﱰة ﻗﺼ ة ﻹﺟﺮاء ﻣﻼﺣﻈـﺎت ا ﺘ ﺎﺑﻌﺔ اﻟﺨﺎﺻﺔ ﺑﻬﻢ . ﻗﺎل اﻟﺒـﺪري :" ﻋﻨـﺪﻣﺎ ﻛﺎﻧﺖ ﻟﺪﻳﻨﺎ ا ﺆﴍات اﻷوﱃ ﻋﲆ اﺣﺘﻮاء اﻟﻨﻈﺎم ﻋﲆ ﺛﻘﺐ أﺳﻮد ، ﻛﺎن ﻟﺪﻳﻨﺎ أﺳﺒﻮع واﺣﺪ ﻓﻘﻂ ﻗﺒﻞ أن ﻳﻜـﻮن اﻟﺠﺴـﻤﺎن ﰲ أﻗـﺮب ﻣﺴـﺎﻓﺔ ﻓﺎﺻﻠﺔ ﰲ ﻣﺪارﻳﻬﻤﺎ . اﻟﻘﻴﺎﺳﺎت ﰲ ﻫﺬه ا ﺮﺣﻠﺔ ﴐورﻳﺔ ﻟﻌﻤـﻞ ﺗﻘـﺪﻳﺮات دﻗﻴﻘـﺔ ﻟﻠﻜﺘﻠـﺔ ﰲ ﻧﻈﺎم ﺛﻨـﺎﺋﻲ ﻟﻘـﺪ ". " ﻛﺎﻧـ ﺖ ﻗـﺪرة ﻣﺮﺻـﺪ ﺟﻴﻤﻴﻨﻲ ﻋﲆ ﺗﻘﺪﻳﻢ أرﺻﺎد ﻋﲆ ﻧﻄﺎق زﻣﻨـﻲ ﻗﺼ أﻣﺮًا ﺑﺎﻟﻎ اﻷﻫﻤﻴﺔ ﻟﻨﺠﺎح ا ﴩـوع إذا . ﻓﺎﺗﻨﺎ ﺗﻠﻚ اﻟﻨﺎﻓـﺬة اﻟﻀـﻴﻘﺔ ، ﻓﺎﺿـﻄﺮرﻧﺎ إﱃ اﻻﻧﺘﻈﺎر ﻟﻌﺎم آﺧﺮ ." ﻳﺼﻌﺐ ﻋﲆ ﻋﻠﻤﺎء اﻟﻔﻠﻚ اﻟﻀﻐﻂ ﺑﺸﺪة ﻋﲆ اﻟﻨﻤـﺎذج اﻟﺤﺎﻟﻴـﺔ ﻟﺘﻄـﻮر اﻷﻧﻈﻤﺔ اﻟﺜﻨﺎﺋﻴﺔ ﻟﴩح ﻛﻴﻔﻴﺔ ﻧﺸﻮء اﻟﺘﻜﻮﻳﻦ اﻟﻐﺮﻳﺐ ﻟﻨﻈﺎم Gaia BH1 ﻋﲆ وﺟﻪ اﻟﺘﺤﺪﻳﺪ . ﻟﻘﺪ ﻛﺎن اﻟﻨﺠﻢ اﻟﺴﻠﻒ اﻟﺬي ﺗﺤﻮل ﻻﺣﻘًـﺎ إﱃ اﻟﺜﻘﺐ اﻷﺳﻮد ا ﻜﺘﺸﻒ ﺣﺪﻳﺜًﺎ أﻛﱪ ﺑﻌﴩـﻳﻦ ﻣﺮة ﻋﲆ اﻷﻗﻞ ﻣـﻦ ﻛﺘﻠـﺔ اﻟﺸـﻤﺲ ﻣـﺎ ﻌﻨﻲ ﻳ ﻋﺎش ﻟ ﻓﻘﻂ ﺒﻀﻌﺔ ﻣﻼﻳـ ﻣـﻦ اﻟﺴـﻨ إذا . ﺗﺸﻜﻞ ﻛﻼ اﻟﻨﺠﻤ ﰲ ﻧﻔﺲ اﻟﻮﻗﺖ ﻓﺈن ﻫـﺬا اﻟﻨﺠﻢ اﻟﻀﺨﻢ ﺳـﻴﺘﺤﻮل إﱃ ﻋﻤـﻼق ﴎﻳﻌـﺎً ﻓﺎﺋﻖ ﻳﻨﺘﻔﺦ وﻳﺒﺘﻠﻊ اﻟﻨﺠﻢ اﻵﺧﺮ ﻗﺒﻞ ﻳﺘﺎح ﻟﻪ إﱃ ﻋﻤﻼق ﴎﻳﻌﺎً ﻓﺎﺋﻖ ﻳﻨﺘﻔﺦ وﻳﺒﺘﻠﻊ اﻟـﻨﺠﻢ اﻵﺧﺮ ﻗﺒﻞ ﻳﺘﺎح ﻟﻪ اﻟﻮﻗﺖ اﻟﻜﺎﰲ ﻟﻴﺼﺒﺢ ﻧﺠـﻢ ﺗﺴﻠﺴﻞ رﺋﻴﴘ ﻳﻘﻮ ﺑ م ﺤﺮق اﻟﻬﻴﺪروﺟ ﻣﺜﻞ اﻟ . ﺸﻤﺲ ﻟﻴﺲ ﻣﻦ اﻟﻮاﺿﺢ ﻋﲆ اﻹﻃﻼق ﻛﻴﻒ ﻛﺎن ﻳﻤﻜﻦ ﻟﻨﺠﻢ اﻟﻜﺘﻠﺔ اﻟﺸﻤﺴـﻴﺔ أن ﻳﻨﺠـﻮ ﻣﻦ ﺗﻠﻚ اﻟﺤﻠﻘـﺔ وﻳﻨﺘﻬـﻲ ﺑـﻪ اﻷﻣـﺮ ﻛـﻨﺠﻢ ﻃﺒﻴﻌﻲ ﻇﺎﻫﺮﻳًﺎ ﻛﻤـﺎ ﺗﺸـ أرﺻـﺎد اﻟﺜﻘـﺐ اﻷﺳﻮد اﻟﺜﻨﺎﺋﻲ . ﺗﺘﻨﺒﺄ ﺟﻤﻴﻊ اﻟﻨﻤﺎذج اﻟﻨﻈﺮﻳـﺔ اﻟﺘﻲ ﺗﺴﻤﺢ ﺑﺎﻟﺒﻘﺎء ﻋﲆ ﻗﻴﺪ اﻟﺤﻴﺎة ﺑﺄن ﻧﺠـﻢ اﻟﻮﻗﺖ اﻟﻜﺎﰲ ﻟﻴﺼـﺒﺢ ﻧﺠـﻢ ﺗﺴﻠﺴﻞ رﺋﻴﴘ ﻳﻘﻮم ﺑ ﺤﺮق اﻟﻬﻴﺪروﺟ ﻣﺜﻞ اﻟ . ﺸـﻤﺲ ﻟ ـﻴﺲ ﻣــﻦ اﻟﻮاﺿـﺢ ﻋ ـﲆ اﻹﻃﻼق ﻛﻴـﻒ ﻛـﺎن ﻳﻤﻜـﻦ ﻟﻨﺠﻢ اﻟﻜﺘﻠـﺔ اﻟﺸﻤﺴـﻴﺔ أن ﻳﻨﺠــﻮ ﻣ ـﻦ ﺗﻠ ـﻚ اﻟﺤﻠﻘــﺔ وﻳﻨﺘﻬـﻲ ﺑـﻪ اﻷﻣـﺮ ﻛـﻨﺠﻢ ﻃﺒﻴﻌﻲ ﻇﺎﻫ ﺮﻳًﺎ ﻛﻤﺎ ﺗﺸـ أرﺻــﺎد اﻟﺜﻘــﺐ اﻷﺳــﻮد اﻟﺜﻨ ــﺎﺋﻲ . ﺗﺘﻨﺒ ــﺄ ﺟﻤﻴ ــﻊ اﻟﻨﻤــﺎذج اﻟﻨﻈﺮﻳــﺔ اﻟﺘــﻲ ﺗﺴـﻤﺢ ﺑﺎﻟﺒﻘـﺎء ﻋـﲆ ﻗﻴـﺪ اﻟﺤﻴـﺎة ﺑــﺄن ﻧﺠــﻢ اﻟﻜﺘﻠ ـﺔ اﻟﺸﻤﺴـﻴﺔ ﻛ ـﺎن ﻳﺠــﺐ أن ﻳﺴﺘﻘﺮ ﰲ ﻣﺪار أﺿﻴﻖ ﺑﻜﺜ ﻣﻤﺎ ﻫـﻮ ﻣﺮﺻـﻮد ﺑﺎﻟﻔﻌـﻞ ــــ ﻗﺪ ﻳﺸ ﻫﺬا إﱃ وﺟﻮد ﻓﺠﻮات ﻣﻬﻤﺔ ﰲ ﻓﻬﻤﻨﺎ ﻟﻜﻴﻔﻴﺔ ﺗﺸﻜﻞ اﻟﺜﻘﻮب اﻟﺴﻮداء وﺗﻄﻮرﻫـﺎ ﰲ اﻷﻧﻈﻤﺔ اﻟﺜﻨﺎﺋﻴﺔ ﻛﻤﺎ ﻳﺸ إﱃ وﺟﻮد ﻣﺠﻤﻮﻋﺔ ﻟﻢ ﻳﺘﻢ اﺳﺘﻜﺸﺎﻓﻬﺎ ﺑﻌﺪ ﻣﻦ اﻟﺜﻘﻮب اﻟﺴـﻮداء اﻟﺨﺎﻣﻠﺔ ﰲ اﻟﺜﻨﺎﺋﻴﺎت . واﺧﺘﺘﻢ اﻟﺒﺪرى ﺑﺎﻟﻘﻮل : " ﻣﻦ ا ﺜ ﻟﻼﻫﺘﻤﺎم أن ﻫﺬا اﻟﻨﻈﺎم ﻻ ﻳﻤﻜـﻦ ﻣﻮاءﻣﺘﻪ ﺑﺴﻬﻮﻟﺔ ﻣﻊ ﻧﻤﺎذج اﻟﺘﻄﻮر اﻟﺜﻨﺎﺋﻴـﺔ اﻟﻘﻴﺎﺳﻴﺔ " إﻧﻪ ﻳﻄﺮح اﻟﻌﺪﻳﺪ ﻣﻦ اﻷﺳﺌﻠﺔ ﺣ ﻮل ﻛﻴﻔﻴﺔ ﺗﺸﻜﻞ ﻫـﺬا اﻟﻨﻈـﺎم اﻟﺜﻨـﺎﺋﻲ وﻳﻤﻬـﺪ ﻻﻛﺘﺸـﺎﻓﺎت ﻣﺴــﺘﻘﺒﻠﻴﺔ ﻟ ﻠﺜﻘــﻮب اﻟﺴــﻮداء اﻟﺨﺎﻣﻠﺔ ا ﺘﻮﻗﻌﺔ ﰲ ﻣﺠﺮﺗﻨﺎ وﻳﺒﻘﻰ أﻳﻀًﺎ ﻟﻐﺰًا ﻳﺠﺐ ﺣﻠﻪ ﺣﻮل اﻟﺴﺒﺐ ﰲ أن اﻟﻨﺠﻢ ا ﺼﺎﺣﺐ ﰲ ﻫﺬا اﻟﻨﻈﺎم اﻟﺜﻨﺎﺋﻲ ﻃﺒﻴﻌﻲ ﺟﺪًا؟ ﻠﺨﺺﻫﺬا اﻟﻔ ﺪﻳﻮ اﻛﺘﺸﺎف أﻗﺮ ﺛﻘﺐ أﺳﻮد إﻟﻰ اﻷرض ] . ﻣﺮﺻﺪ ﺟ ﻤ اﻟﺪوﻟﻲ ﻳﻨﺎﻳﺮ ﻓ اﻳﺮ 2023