Stars range in (surface) temperature from about 3500 K to 50,000 K
 Their temperatures correlate with mass and luminosity (massive stars are hot and very bright): a 50,000
 K star gives of a
 million times the luminosity of the Sun (Tsun = 6000 K)
 Stars hotter than about 8000 do not have convective outer layers - no convection - no dynamo - no hot
 corona…
 …no
 X-rays