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This supernova will be very important for figuring out what Type Ia SNe are. As Phil Plait mentions, astronomers only know that white dwarfs are involved, but
by splat 13y ago
This supernova will be very important for figuring out what Type Ia SNe are. As Phil Plait mentions, astronomers only know that white dwarfs are involved, but there are several competing models as to how the white dwarf(s) explode. One of the main ways we will be able to distinguish between these models is by observing what the supernova looks like long after the explosion since this is when the shock will be interacting with distant material. Because this supernova is so close we will be able to observe it long after the explosion and will therefore be able to observe its interactions with very distant material.
This is important because the so-called single-degenerate model in which a red giant dumps material onto the white dwarf is expected to produce very faint hydrogen lines. Observing these hydrogen lines in the spectrum would be a smoking gun for the single degenerate model. On the other hand, if they are not observed, it would put very tight constraints on how the single degenerate model could work.
Another reason these observations will be useful is that head-on collisions between white dwarfs are expected to produce two separate explosions with different velocities -- this then produces double peaks in the spectral lines [1]. Sometimes these are hard to observe because the SNe are so far away, however. They will be most easily observable in this SN. If they're found it would be a smoking gun for a head-on collision between two white dwarfs.
[1] http://arxiv.org/abs/1401.3347 http://arxiv.org/abs/1401.3347
- InclinedPlane 13y agoMy understanding is that there are three competing theories which have the strongest claim on explaining Type Ia supernovae. The classic theory is that a non-white dwarf companion star feeds material onto a white dwarf, which increases its mass. This kicks off a complicated chain of events, some of which may occur over timescales of a thousand years, ultimately culminating in the initiation of fusion reactions (initially Carbon, then Oxygen) in the core of the white dwarf. The fusion reactions release heat, but because the white dwarf is already under electron degeneracy conditions it is unable to increase pressure and expand to moderate the fusion reactions, so instead they are caught in a very strong positive feedback loop. In a matter of seconds the fusion reactions consume all of the Carbon in the star and then begin consuming the Oxygen in the inner core, this process releases more than enough energy to completely unbind the star gravitationally, the star explodes in a supernova. Alternately, it's also possible that a white dwarf star could have more than enough mass to undergo a Type Ia explosion but is kept in check by rapid spinning. As the star ages and the spinning slows down it crosses a boundary where the above events occur. Or, two white dwarfs could instead merge with each other. It's actually likely, in my opinion, that all three models contribute to Type Ia events in nature, but it's currently unknown which variety is the most common cause of such supernovae.
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