Chapter 15- Properties of Stars Flashcards
properties of stars
-power source
-density
-age
-size
-temperature
-composition
-distance
-motion
-mass
-luminosity
PDASTCDMML
spectroscopy
measuring spectral lines
how could we go about proving that stars are like our sun, only farther away
confirm that the luminosity is similar to the suns
how do we determine luminosity
- with brightness and distance
- measured in watts
solving for brightness
the inverse square law
parallax
- apparent movement of foreground object relative to some background due to change in the observers location
- best way to measure distance
stellar brightness
lower numbers are brighter and higher numbers dimmer
apparent magnitude
based on how bright object appears from earth
absolute magnitude
how bright the object would be if it were 10 parsecs away
is the suns absolute magnitude higher or lower than its apparent magnitude
higher
how can we determine temp
temp determined by where star “peaks” on electromagnetic spectrum
spectral classification chart
OBAFGKM
-hottest stars to coolest stars
what do absorption lines tell us
ionization and ionization tells us the temp
-therefore absorption lines tells just the temp
spectral type
each spectral class is broken down into 10 subclasses
size, volume, mass differences
size= how big(radius)
volume= how much space
Mass=How much stuff
stellar mass
use keplers third law is how you find the stellar mass, but you have to have 2 or more Stellar binaries
spectroscopic binary
- astronomers can’t see both stars
- detected through Doppler Shifts in spectral lines
eclipsing binary
- one star periodically blocks the light of other star
- can give astronomers both mass and size
what does being in the main sequence mean
when stars are undergoing thermonuclear fusion of hydrogen and helium in their core
visual binary
when astronomers can see both stars
luminosity class
tells you about luminosity and size
how much mass a star has relates to what
- the stars life expectancy
- low mass=long lifetime
- high mass=short lifetime
what does star clusters tell about stars
- all stars are around the same age
- star formation makes many more low mass stars then high mass stars
open cluster
a few thousand loosely park stars
globular cluster
up to a million or more stars in a dense ball bound together by gravity
