Stellar Evolution Tutorial V1.0.demo

• Introduction

• The following pages are a first attempt at explaining stellar evolution in a phenomenological, rather than quantitative, way. The aim is to give you an informed overview of the physics of the various stages, the things that occur, and importantly, the nucleosynthesis which occurs. The graphs are from recent calculations (details given below) and are not schematic (unless explicitly stated). But don't worry about the numbers. Its the overall behaviour that is important.
• Obviously these pages cannot teach you all the maths and physics you need to understand the evolution! It is assumed that you have enough background in that already. These pages are perhaps best used as an adjunct to a normal course in stellar evolution and nucleosynthesis.
• My own interest is in explaining the complex behaviour of AGB stars to non-experts. But the rest of the tutorial, from the ZAMS to the AGB, is a required background and is suitable for courses which do not go as far as the AGB evolution, or are not interested in the nucleosynthesis.
• I am seeking comments on how to improve these presentations, so please feel free to email me with comments and criticisms. Any suggestions for clarification, in text of graphs, would be welcome.
• A note on time.... The movies show time-dependence, but its important to realise that this is not linear! In fact, the times were chosen to illustrate features of the evolution. The frames were picked so that the feature we were looking at was clearly seen, independent of the time. This means that sometimes the time between successive frames is dramatically different. In the movies with two frames next to each other, one of the frames usually indicates the time, so in those cases the rate of the movie is obvious. But beware that in other cases the times between frames may vary a lot!
• I tried to make the labels large, without taking up too much space in the graph. Some of the lines are too thick, I now realise. These will be fixed in the next version.
• Note that not all movies are included here, and neither is all text. This is a sample version of a product in development. For a complete and updated version please contact us at Cantanout.
• Some of the movies show two frames at a time, such as the internal evolution and the corresponding position in the HR diagram. For these movies you have the choice of the two frames appearing either horizontally (graphs next to each other) or vertically (one above the other). Choose whichever fits your screen best.
• Please note: no stars were harmed during the making of these movies....

• Overview

• We will follow the evolution of two stars, from the main-sequence through to the thermally-pulsing AGB, which is essentially the end of their lives. We have chosen two masses: M=1 Msun and M=5 Msun; both have essentially a solar composition with X=0.6872, Y=0.2928 and Z=0.02.
• The figure below shows the evolution of both stars and identifies the Early-AGB and the Thermally-Pulsing AGB.
  

• Evolution for M = 1 Msun and Z=0.02

• Evolution prior to the AGB is here
• AGB Evolution is qualitatively similar to the M = 5 case here

• Evolution for M = 5 Msun and Z=0.02

• Evolution prior to the AGB is here
• AGB Evolution is here

• Asymptotic Giant Branch Evolution (for M = 5 Msun and Z=0.02)

• Early AGB Evolution here
• Anatomy of a Thermal Pulse here
• Two Consecutive Thermal Pulses here

• Nucleosynthesis on the AGB (for M = 5 Msun and Z=0.02)

• General nucleosynthesis here
• Nucleosynthesis in thermal pulses is here
• Nucleosynthesis by Hot Bottom Burning here