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    Question ID:   16428         Current Version: 1
Question: What is known about isotopic abundances in supernova remnants from X-rays and gamma-rays?
Category: Science > Astronomy & Space
Keywords: X-rays, gamma rays, isotopic abundances, supernova remnants
Type: what
Rating:(0 ratings)    Views: 111    Discussions: 0   In Watch Lists: 1  

 
    Answer:
X-rays and gamma-rays can help us understand the isotopic abundances from supernovae. However, only for particular radioactive isotopes.

In a supernova explosion many elements and isotopes are created, mostly through the rapid process (r process). However, most of these are unstable so they decay down to a stable or more stable isotope. It is during this decay process that they give off gamma-rays. The energy of the gamma-ray will depend on the particular isotope and the process involved. These gamma-rays are observed as spectral lines within the overall spectrum.

Now a word about 1/2 life. The 1/2 life of a particular isotope is the time it takes for half of the initial quantity of the isotope to decay. So, observing a supernovae early on one can observe a number of these spectral lines, however over time they fade as there become fewer radioactive isotopes and more stable isotopes.

For example, the element Titanium 44 decays with a 1/2 life of about 70 years. The decay process gives off 1 MeV, 60 and 70 keV photons. By counting these photons, the mass of Ti 44 produced in the supernova explosion can be estimated.

Source: NASA
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