The burning of this element occurs as the very brief final stage of nuclear fusion in post-main-sequence stars. For 10 points each:
[10h] Name this element whose fusion leads eventually to an iron core. Type Ia (“one-A”) supernovae are distinguished from type Ib and type Ic supernovae by the presence of a strong absorption band at 615 nanometers corresponding to this element.
ANSWER: silicon [or Si; accept silicon burning or silicon fusion]
[10e] In silicon burning, silicon nuclei successively fuse with these particles. Photodisintegration of these particles produces two protons and two neutrons, since they are equivalent to helium-4 nuclei.
ANSWER: alpha particles [or alpha rays or alpha radiation]
[10m] After fusion stops, mechanisms like photodisintegration and electron capture remove degeneracy pressure support for the star, accelerating this process. Type Ia supernovae uniquely do not result from this process.
ANSWER: core collapse [accept core-collapse supernova; prompt on collapse]
<Other Science>