Sunday, February 26, 2023

3890 - SUPERNOVA - shock waves create elements?

 

-  3890  -    SUPERNOVA    -  shock waves create elements?    Some elements arrived on Earth by surfing supernova shock waves.  When stars die, they spread the elements they’ve created in their cores out to space. But, other objects and processes in space also create elements. Eventually, that “star stuff” scatters across the galaxy in giant debris clouds.


-------------  3890  -   SUPERNOVA    -  shock waves create elements?

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-   Millions of years the debris clouds  settle onto planets.  How did heavy elements like manganese, iron, and plutonium show up on Earth? It turns out they’re made in different processes, often in different parts of the Milky Way. Yet, they’ve been found layered together on Earth’s seabed. That implies they arrived about the same time, despite their different origins.

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-     These elements from faraway events are carried by supernova shock fronts just like surfers catching a wave. 

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-     First, there are the Type II supernovae. They occur when a supermassive star dies. That supernova is one at least eight times the mass of the Sun. These stars fuse heavier and heavier elements in their cores. When they get to creating iron, they don’t have enough energy to keep up the production line. The cores collapse and then everything expands outward very rapidly in a supernova explosion. That’s enough to send its heavy elements racing through space.

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-  Next, there are Type Ia supernovae. These happen in a binary pair of stars. Material from a main-sequence star accretes onto its partner, a white dwarf. When too much material accumulates, there’s an explosion. That results in the “nucleosynthesis” of heavier elements, including manganese.

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-    Another catastrophic event that likely creates heavy elements is the collision, or merger,  of two neutron stars. As they spiral in toward each other and eventually smash up, they release a shower of neutrons. Those, in turn, bombard nearby atoms. This “r-process” event very quickly produces heavy elements such as plutonium.

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-      Somehow, all this material from different sources ended up on Earth at about the same time. Scientists found puzzling evidence of that in radioactive isotope deposits on the seabed in 2021. They weren’t formed normally on Earth or during the birth of the solar system some 4.5 billion years ago. They had to come from somewhere else.

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-    Getting elements from there to here.   Isotopes can propagate through large areas of a galaxy via supernova shock waves. These fronts sweep up collections of elements from various sites.   Understanding this delivery process is particularly crucial as astronomers begin large-scale studies of exoplanets where life might be possible.

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-     It’s a very important step forward, as it not only shows us how isotopes propagate through the Galaxy but also how they become abundant on exoplanets beyond our solar system.

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-    Isotopic abundances are a strong factor in determining whether an exoplanet is able to hold liquid water, which is key to life. In the future, this might help to identify regions in our Galaxy where we could find habitable exoplanets.

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            February 25, 2023    SUPERNOVA    -  shock waves create elements?     3890                                                                                                                           

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--------------------- ---  Sunday, February 26, 2023  ---------------------------

 

 

 

 

         

 

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