E.5 Fusion and stars

• Stars are stable when outward radiation pressure balances inward gravity.

• Fusion is a source of energy in stars.

• Fusion in stars requires high density and temperature.

• Stellar mass determines star evolution pathway.

• Use HR diagram regions to describe star properties.

• Include main sequence, red giants/supergiants, white dwarfs and lines of constant radius.

• Stellar parallax distance: d(pc)=1/p(arcsec).

• Determine stellar radius from luminosity and surface temperature.