MSGID: 1:317/3 640177e6   
   PID: hpt/lnx 1.9.0-cur 2019-01-08   
   TID: hpt/lnx 1.9.0-cur 2019-01-08   
    Resurrected supernova provides missing-link    
      
     Date:   
         March 2, 2023   
     Source:   
         National Institutes of Natural Sciences   
     Summary:   
         Astronomers have discovered a supernova exhibiting unprecedented   
         rebrightening at millimeter wavelengths, providing an intermediate   
         case between two types of supernovae: those of solitary stars and   
         those in close-binary systems.   
      
      
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   FULL STORY   
   ==========================================================================   
   Astronomers have discovered a supernova exhibiting unprecedented   
   rebrightening at millimeter wavelengths, providing an intermediate case   
   between two types of supernovae: those of solitary stars and those in   
   close-binary systems.   
      
      
   ==========================================================================   
   Many massive stars end their lives in a catastrophic explosion known as   
   a supernova (SN). Supernovae increase rapidly in brightness, and then   
   fade over the course of several months.   
      
   Astronomers have long known that the presence or absence of a close   
   binary companion can affect the evolution of massive stars. In a close   
   binary system, gravitational interactions with the binary companion   
   will strip large amounts of material from the SN progenitor long before   
   the final explosion. In these cases, the progenitor will be quiet up   
   until the time of the actual SN. On the other hand, in the case of an   
   SN progenitor with no binary companion or a distant companion, leading   
   up to the SN explosion the progenitor will keep most of its initial mass.   
      
   Of course smart alecs will ask, "What happens when the binary is not   
   too close and not too distant?" Not just smart alecs, astronomers also   
   wanted to know.   
      
   The break came when an international research team, led by Keiichi   
   Maeda (Professor at the Graduate School of Science, Kyoto University)   
   and Tomonari Michiyama (ALMA Joint Postdoctoral Fellow at the Graduate   
   School of Science, Osaka University), used ALMA (The Atacama Large   
   Millimeter/submillimeter Array) to monitor a supernova known as SN 2018ivc   
   as it dimmed for about 200 days after the initial explosion. The results   
   showed that SN 2018ivc was an unusual object, so the team decided to check   
   up on it again, at about 1000 days after the explosion. They found that   
   the object was actually rebrightening, the first time this phenomenon   
   had ever been observed in millimeter wavelength radiation.   
      
   Comparison to numerical modeling suggests that interaction with an   
   intermediate-distance binary companion about 1500 years before the SN   
   explosion created a large hollow shell of circumstellar medium. At 200   
   days after the SN, the ejecta flying out from the explosion had yet to   
   reach the shell. Then sometime between 200 and 1000 days, the ejecta   
   collided with the circumstellar medium.   
      
       * RELATED_TOPICS   
             o Space_&_Time   
                   # Stars # Astrophysics # Nebulae # Space_Telescopes #   
                   Astronomy # Asteroids,_Comets_and_Meteors   
       * RELATED_TERMS   
             o Supernova o Gravitational_wave o Extrasolar_planet   
             o Interstellar_medium o Nuclear_fusion o   
             Neptune's_natural_satellites o Open_cluster o   
             Uranus'_natural_satellites   
      
   ==========================================================================   
   Story Source: Materials provided by   
   National_Institutes_of_Natural_Sciences. Note: Content may be edited   
   for style and length.   
      
      
   ==========================================================================   
   Journal Reference:   
      1. Keiichi Maeda, Tomonari Michiyama, Poonam Chandra, Stuart Ryder,   
      Hanindyo   
         Kuncarayakti, Daichi Hiramatsu, Masatoshi Imanishi. Resurrection   
         of Type IIL Supernova 2018ivc: Implications for a Binary   
         Evolution Sequence Connecting Hydrogen-rich and Hydrogen-poor   
         Progenitors. The Astrophysical Journal Letters, 2023; 945 (1):   
         L3 DOI: 10.3847/2041-8213/acb25e   
   ==========================================================================   
      
   Link to news story:   
   https://www.sciencedaily.com/releases/2023/03/230302093414.htm   
      
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