Chapter 12 Flashcards
energy per second =
watts
apparent brightness =
amount of starlight that reaches the earth
brightness = (equation)
luminosity/4pi(distance)^2
1 mag star is..
100 times brighter than 6 mag. Star
-smaller the # the brighter the object
Venus =
-4
full moon =
-12
sun =
-27
hottest to coolest (spectral type)
O B A F G K M
Only Boys Accepting Feminism Get Kissed Meaningfully
sun is how many times brighter than the moon?
1 million
an HR diagram plots the ______ and ______ of stars
luminosities and temperature
how many percent of stars fall in main sequence? (even sun)
90%
which stars are the most numerous?
M Stars
what type of star is the sun?
G type
main sequence stars are fusing _____ into _____ in their cores, like the Sun.
fusing hydrogen into helium
Luminous main sequence are
hot (blue)
less luminous ones are
cooler, (yellow or red)
the mass of a normal hydrogen burning star determines what?
its luminosity spectral type and lifetime
high mass main sequence stars
high luminosity
short lived
large radius
blue
Low mass main sequence stars
low luminosity
long lived
small radius
red
whats the magic number?
10 million
when did all stars become larger and redder?
After exhausting their core hydrogen
giants and supergiants
what tells us its age?
the main sequence turn off point of a cluster
what has no stars with a life expectancy less than around 100 million years
Pleiades
