Possibly useful formulae:
Doppler Shift: ; Distance(parsecs)
Stephan's Law: Energy/area Temp ; Intensity
a) What are their relative distances b) what are their relative luminosities?
___ stellar apparent brightness vs. stellar distance
___ stellar luminosity vs. stellar distance
___ stellar apparent brightness vs. stellar surface temperature
___ none of these
___ Red giants have very little hydrogen in their atmospheres
___ Most of the hydrogen has been ionized in these cool stars
___ Most of the hydrogen atoms have their electrons in the ground state and therefore can't absorb visible light photons
___ This is another of Bolte's trick questions - the coolest stars have the strongest hydrogen absorption lines
___ 0.1 parsec
___ 10 parsec
___ 10 light-years
___ it depends on the amount of dust between us and the star
a) How would the apparent brightness of the Sun change? b) How would the luminosity of the Sun change?
a) Compare the energy generated per unit surface area for these two stars. b) If Star A is the same luminosity as star B, compare the relative sizes (either surface area or radius, but specify which) of the two stars.
___ Star C is more luminous than Star D
___ Star C and Star D have the same temperature
___ Star D is more distant than Star C
___ Star C must be a giant
a) Compare the luminosities of Star E and Star F if Star E has a higher surface temperature and twice the distance of Star F. b) Compare the masses of Star E and Star F from part (a).
a) What type of system is this very likely to be? b) What property of stars can be measured from such systems?
___ The surface temperature of the star
___ The chemical composition of the star
___ The amount of interstellar reddening in the direction of the star
___ The size of the telescope used to observe the star