Stellar Thermonuclear Explosions

A binary system of a main-sequence star like our sun, and a small dense object called white dwarf, are circling each other in a tight dance. The neutron star continuously accretes hydrogen-rich material from its companion star, which heats as it falling down to the white dwarf's surface. At some point the temperature on the surface of the white dwarf is so high, that a thermonuclear explosion is ignited. The released energy is so huge that for us, here on earth, it seems like a new star was born in the sky. We called this phenomena "nova", which stands for "new" in Latin.


In other cases, the binary system contains a neutron star instead of a white dwarf. Those systems results in a much stronger eruption, which we call an x-ray burst.

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Nuclear Data Input

When we look at an x-ray burst, we see neither a neutron star nor a main-sequence star. What we see is the amount of light varies in time, or a "light curve". If we wish to understand this light curve, we need to write computer simulations, containing all the relevant physics that we know. 

In this simulation by H. Schatz et al., you can see the proton-rich isotopes created in such burst, and how its creates a light curve. Such simulation involves a lot of nuclear physics, which is very hard to study. 

Experimental study of those nuclear reactions is one of the main research interest of our group.

 

β-delayed charged-particle emission

It is hard, very hard, to directly measure rates of nuclear reactions, when the involved particles tend to decay within minutes, or even sub-seconds. Instead, physicists are using tricks to obtain the information they need.

 
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