Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Mechanism for generating the energy in supernova

  1. Jan 12, 2013 #1
    In a type II supernova If I remember correctly the core of the star collapses and turns to a neutron star. The envelope then will accelerate towards the core. The energy then come from the release of the kinetic energy of the infalling particles as they are brought to an abrupt stop by the incredibly dense surface of the neutron core. Can anyone shed any light on this idea for me please.
     
  2. jcsd
  3. Jan 12, 2013 #2

    mathman

    User Avatar
    Science Advisor
    Gold Member

  4. Jan 12, 2013 #3

    Chronos

    User Avatar
    Science Advisor
    Gold Member

    The pressure required to compress matter to 'neutronium' is much greated than exists even in giagantic stars. According to theory, when a star accumulates enough iron in its core to surpass the Chandrasekhar limit, the core collapses triggering a supernova eruption [hence the term core collapse supernova]. The extra pressure furnished by the collapse supplies the force necessary to create a neutron star. The great majority of neutron stars are at or below the Chandrasekhar limit of 1.4 solar masses.
     
    Last edited: Jan 12, 2013
  5. Jan 12, 2013 #4

    Drakkith

    User Avatar

    Staff: Mentor

    Is there a paper or something somewhere that explains step by step what happens during the collapse? Something with a little more detail than wikipedia?
     
  6. Jan 12, 2013 #5

    Chronos

    User Avatar
    Science Advisor
    Gold Member

  7. Jan 12, 2013 #6

    Drakkith

    User Avatar

    Staff: Mentor

    Awesome, thanks Chronos.
     
  8. Jan 12, 2013 #7
    Yes an awesome document thank you Chronos, and thanks to everyone else for the responses. It is the bounce I was particularly interested in. It was something I remembered from a lecture on my degree course. It was the idea that gravitational energy of the in falling matter as struck it the surface of neutrons at nuclear densities. I am developing some resources for my colleagues for use in secondary schools and sixth form colleges. It is such an interesting topic to the students and there is very little information to feed the thirst they have for knowledge about the physics of the situation.

    It is this statement on page 3 of the reference above from Chronos that I would really like help interpreting if possible

    “The abrupt halt of the collapse of the inner core and its rebound generates a shock wave as the core’s outer half continues to crash down. Once it was thought that this bounce might actually be the origin of the supernova’s energy (3,4), that the outward velocity of the bounce would grow as it moved into the outer layers of the core and
    eject the rest of the star with high velocity. Now it is known that this does not occur. Instead, the shock wave stalls due to photodisintegration and copious neutrino losses. A few milliseconds after the bounce, all positive velocities are gone from the star and the dense, hot neutron-rich core (commonly called a proto-neutron star) is accreting
    mass at a few tenths of a solar mass per second.”
     
  9. Jan 12, 2013 #8

    Chronos

    User Avatar
    Science Advisor
    Gold Member

    Many questions remain about the exact details of the explosive phase. This paper may offer some insight: Explosion Mechanisms of Core-Collapse Supernovae, http://arxiv.org/abs/1206.2503
     
  10. Jan 13, 2013 #9

    Drakkith

    User Avatar

    Staff: Mentor

    Wow, thanks again Chronos. Those were awesome papers.
     
  11. Jan 13, 2013 #10

    Chronos

    User Avatar
    Science Advisor
    Gold Member

    I have an obsession with neutron stars due to my unnatural curiousity about the apparent mass gap between neutron stars and stellar mass black holes. I blame it all on Farr, et al: The Mass Distribution of Stellar-Mass Black Holes, http://arxiv.org/abs/1011.1459.
     
  12. Jan 14, 2013 #11

    Ken G

    User Avatar
    Gold Member

    You've already had your answers, so I'll just correct one minor point: you are talking about "core collapse" supernovae, which are not quite the same thing as type II supernovae. A simpler way to think of it is that all supernovae are core collapse except type Ia, which are thermonuclear explosions.

    You might think that if we have a type I and a type II, and we have thermonuclear and core collapses, we'd just associate the two, but astronomy never makes that much sense! In astronomy, it is customary to use specific observable features when classifying, and figure out the physics later, so you invariably end up with classifications that don't fit the physics very well (think "planetary nebula", etc.). In the case of supernovae, type I just means that it is absent of hydrogen lines, and type II means it does have hydrogen lines. Since core collapse can occur in helium stars, you can have type I that are core collapse (and there is a zoo of other possibilities as well). Type Ia is also classified based on observations, but the physics works out that this is the type that is not a core collapse (I don't know of any others, but there may be all kinds of fundamentally different kinds of physics going on).
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Mechanism for generating the energy in supernova
  1. Supernova energy (Replies: 2)

  2. Energy in supernovae (Replies: 2)

Loading...