Mass Loss from Giant Stars
		• Envelope of red giant very loosely held – Star is so big, gravity very weak at the surface • Degenerate core makes nuclear “thermostat” sluggish – Core doesn’t quickly expand and cool when fusion is to fast – Energy can be generated in “thermal pulses” • Low temperature opaque envelope can also “oscillate” – Energy is transmitted in “pulses” as envelope expands and contracts – Main cause of “Variable Stars”
	• Some Red Giants have very strong stellar winds ejecting envelopes, forming “Planetary Nebulae” • PN called this because some looked like planets in poor telescopes • PN don’t have anything to do with formation of planets