PX282 - E6 - higher mass stars
-
they evolve similarly to low-mass stars, up to AGB, but they burn faster with no helium flash
-
fusion can continue, potentially up to iron
-
C-burning
- temperature
- forms Ne, Na and Mg
- lasts about
years
- temperature
-
O-burning
- a temperature
- forms Si, P, S and Mg
- lasts about
days
- a temperature
-
Si burning
- forms Fe,
- lasts about 2 days
-
a shell structure forms with an degenerate iron core
-
if the mass of the core goes above the chandrashekhar limit
, it collapses, resulting in a supernova -
this is a gravitational collapse, ie. a free fall timescale
-
as the inner core collapses, eventually the strong nuclear force causes a bounce-back
-
this causes a substantial energy release of
-
about 1% of it is kinetic energy released as neutrinos in about
-
observationally, such core-collapse supernovae are labelled type
, , -
the outer layers fall slower and they are suspended over the collapsing core
-
a lot happens in a short time
-
the core collapses in seconds, while the shockwave takes hours to reach the surface
-
a large quantity of
-elements is produced