Supernovae Flashcards
Type I
do not have hydrogen lines
Type II
have hydrogen lines
Type IA
show certain silicon lines
Type IB
don’t show silicon line but do show helium
Type IC
don’t show silicon or helium
Which SN are due to core-collapse?
II, IB, IC
Describe massive core-collapse.
> 8 solar masses. core grows too massive for degenerate e- pressure support. core collapse - neutrinos carry away energy. repulsion stops further collapse. leaves compact object.
what is different in the massive core-collapse which produces IB and IC SN?
IB - H layer already shed
IC - H and He already shed
What are the models for production of IA?
SD: WD accretes from a companion star.
DD: merger of two WD in binary system.
Why are IA SN are good standard candles?
rise quickly to similar peak luminosity before slowing after 50 days
Describe SNR.
ejected material from star expands into ISM. Drives shocks that heat and sweep up ISM in roughly spherical region.
Describe Crab-like (Plerions) SNR.
filled with synch. from radio to X-ray. Central radio source (pulsar)
Describe Shell-like SNR.
radio, optical, X-ray emission from outer shell. no central source.
What is interesting about the Crab nebula?
There are breaks in the spectrum. At different energies, the radiation is affected differently by energy loss.
Describe the process of Single-Degenerate SN formation.
WD accretes material from normal star in binary orbit until nearly reaches Chandrasekhar limit, increasing density and temp. lead to runaway carbon fusion which ignites a SN.
Evidence for and against the Single-Degenerate model.
No evidence of companion star near Ia SN.
Explains similar lightcurves and peak luminosities as all start same mass.
Which type of SN leads to Crab-like SNR?
II. Leave behind a pulsar.
Which type of SN leads to a shell-like SNR?
Ia. No central source. Synchrotron cooling leads to empty shell if no pulsar.
