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What you will learn in Stars and Stellar Evolution
1. How bright is a star?
The scale astronomers use for brightness runs backwards, and it has for two thousand years. Sirius is −1.46; the faintest star you can see is +6.
2. Colour and temperature
Red stars are the cool ones and blue stars are the hot ones. Every tap, warning light and heat map you have ever used teaches the opposite.
3. The HR diagram
Plot every star by colour and true brightness and they do not scatter: they fall on a few lines. Which lines you see depends on which stars you chose to plot.
4. Mass decides everything
One number sets a star's brightness, its size, its colour, how long it lives and how it dies. The widget has one slider because the physics has one input.
5. What powers a star
The Sun is not burning. A chemical fire of the Sun's mass would last a few thousand years, and that calculation is what told nineteenth-century physicists something was missing.
6. The iron wall
Fusion releases energy up to iron and costs energy beyond it. That single fact ends the star, and it is a statement about the binding-energy curve rather than about stars.
7. How stars die
White dwarf, neutron star or black hole. Which one is decided by the mass the star started with, and the boundaries between them are soft.
8. Where the elements came from
The oxygen in your blood was made in a massive star, the carbon in your cells in a dying red giant, the iron in your haemoglobin in an exploding white dwarf. This is not a metaphor and the table is checkable.
9. Measuring the distance to a star
A class of star whose pulse period tells you its true brightness. Compare that against how bright it looks and the distance falls out — the method that first showed the universe was bigger than the Milky Way.