Type 1a supernova (emits singly Ionised Silicon Si II)

[yeletah]

Hi

in the context of a type1a suprnova, which is how they are identified by strong ionised silicon spectra lines, i.e. SI II  is absorbing 635.5 nm.

Can anyone tell me how singly ionised silicon is generated?

is a result of fusion between carbon  & oxygen?

and if so why those two elements? in a type 1a supernova

Thanks

Steve

[Knight of Clear Skies]

I think Silicon is produced by Oxygen-burning, the fusing of two oxygen nuclei to form Silicon and Helium. I would think that Oxygen is depleted in stars massive enough to burn Oxygen in their cores, which would be why Type 1b and 1c Supernova don't show the Silicon absorption line in their spectra.

[ronin]

Silicon appars to come from Oxygen burning, however O+O can give rise to several outcomes, 2 of which are Silicon, different isotopes, at the end.

http://en.wikipedia.org/wiki/Oxygen-burning_process

This occurs before the star goes supernova, but I suspect not a long time before it goes.

[yeletah]

Thanks

Am I correct in thinking this ionised silicon is produced from the oxygen burning process in vast quantities and is a prominent gas when the star explodes, hence the absorption lines?

Also if a type 1a supernova is being fed from a red giant partner, hydrogen, why is their no hydrogen gas in the explosion and hence hydrogen absorption line?

(Type 1a are apparently identified by no hydrogen or helium absorption lines, mainly ionised silicon.)

[Merlin66]

This may be of interest......

[yeletah]

Thanks, thats really good diagram.