Type 1b/c supernovae formation?

Question

Can anyone tell me what kind of stars form type 1b/c supernovae, and why they do this ? I know they are formed from high mass stars, but i have no idea what seperates them from type ll supernovaes.

Thanks.

Answer 1

<from wikipedia>

http://en.wikipedia.org/wiki/Type_Ib_and...

Type Ib supernovae are believed to originate in an event nearly identical to a Type II supernova, in which a massive star suffers collapse at the core. However the progenitor star of a Type Ib supernova has expelled its outer shell of hydrogen prior to explosion. Instead the outer shells of these stars consists primarily of helium, resulting in a spectrum more like a Type Ia supernova. Type Ic supernovae are distinguished from Type Ib in that the former also lack lines of helium.

Formation



The onion-like layers of an evolved, massive star (not to scale).Prior to becoming a supernova, an evolved massive star is organized in the manner of an onion, with layers of different elements undergoing fusion. The outermost layer consists of hydrogen, followed by helium, carbon, oxygen, and so forth. Thus when the outer envelope of hydrogen is shed, this exposes the next layer that consists primarily of helium (mixed with other elements). This can occur when a very hot, massive star reaches a point in its evolution when significant mass loss is occurring from its stellar wind. Highly massive stars (with 25 or more times the mass of the Sun) can lose up to 10-5 Solar masses each year (or the equivalent of a solar mass every 100,000 years.)

The progenitors of Types Ib and Ic have lost most of their outer envelopes due to strong stellar winds or else from interaction with a close companion of about 3–4 solar masses.

Answer 2

I'm not one hundred percent sure but i think i remember coming across an article saying the differences was in the gasses that make up the supernovae...unfortunately i cannot recall those gasses at this time.