Test 2

Luminosity

amount of power a star radiates (does not depend on distance)

apparent brightness

the amount of starlight that reaches earth

Distance

1r:1. , 2r:1/4, 3r:1/9

Magnitude

negative bright positive dark

Absolute magnitude

how bright 0 parsecs away

apparent mag> abs mag

star is farther than 10 parsecs

Apparent < absolute

closer than 10 parsecs

Stellar parallax

star appears at two different positions in the sky during earths different seasons

d=1/p

p in arc seconds, d in parsecs

higher temperature

bluer star

Lower temperature

Redder star

star can have high total luminosity if…

its hot and heavy

main sequence stars

convert h to he in core

low mass stars

white dwarfs

High mass stars

neutron star

Very large

black hole

All stars in star clusters are…

the same age and the same distance from earth

With 10 parsecs…

absolute fainter than apparent