Question 2) Stealth Fusion We\'re going to explore how the Universe ends up maki

Question

Question 2) Stealth Fusion We're going to explore how the Universe ends up making elements past iron. If a solar system starts with two massive stars, and each goes supernova, what used to be the two cores can remain orbiting each other. A) What material are those two hot glowing cores likely made of? [Hint: if we can still see them, what objects are we talking about?] B) Those two cores can end up merging and making a third (!) supernova. Some of the material those cores are made of gets thrown out into space and hits the nuclei of other atoms. Why is adding that substance to nuclei easier than normal fusion [Hint: why is normal fusion difficult?]? C) Having accomplished Part B, think about the balances that exist for atoms and tell me how those atoms are going to become very heavy elements

Explanation / Answer

The life cycle of a massive star ends in a supernova with the remnant being either a neutron star or a black hole. This depends on the initial mass of the star.

But sometimes, when a star is only slightly massive, it can undergo a type I supernova. The outer envelope is blown away. This stage is called white dwarf.

A. Since the remnants are still visible, the remnant must be white dwarf. The material that the remnant is likely to be made of is Iron since this is the last element formed before type I supernova. These white dwarfs are called Iron-core white dwarf.

Neutron stars also form a candidate but optical neutron stars are very rare and extremely hard to detect.

B. Binding energy per nucleo of iron (the last element formed before white dwarf is formed) is 8.8 keV which is very high. At this point, the energy required for fusion is much higher than the energy produced during fusion. Due to this reason, it is much easier to add substance to the nuclei than for fusion.

C. The temperatures reached during the supernova is very high and the matter is very energetic. At this energy, it is much easier to add the thrown out material to the nuclei of the atoms in the space. Due to this reason, heavy elements are formed during supernova.

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