Astr 222 Jan 10 2004: Stellar evolution and supernovae  

Star Clusters and Stellar Evolution

High Mass evolutionary tracks

Question: what nuclear reactions are going on?

Question: What is the brighter sequence?

Question: Where do we find binary systems on HR diagrams?

Open Cluster Image

Open cluster NGC 3293 --CMD

CMD with evolutionary tracks and ages

Question: where are the stars that evolved off the main sequence?

Question: How might the HR diagram of a galaxy be different?

CMD of Local Group dwarf galaxy Leo I

Models of Leo I CMD with different ages

Star formation history of Leo I

Supernovae

Supernovae

Type II Supernovae

SN 1987A light curve

Radioactive Decay Core Collapse and Pre-Supernova

Reverse Beta Decay

Question: What determines how much closer particles need to be for neutron degeneracy?

Answer: Ratio of neutron to electron masses

Question: What conditions are necessary for neutrinos to transfer heat effectively?

Fig from Fryer et al 2002: Isosurface of material with radial velocities of 1000 km s-1 for models A, B, and C. The isosurface outlines the outward moving convective bubbles. The open spaces mark the downflows.

Figure of velocity flows: Slice of supernova model, colored by its entropy and showing velocity vectors. The cold, low-entropy material flows downward as the high-entropy material bubbles upward.