ASTRONOMY 101 EXAM 3 QUESTIONS
AND ANSWERS 100% CORRECT!!
, The total amount of power (in watts, for example) that a star radiates into space is
called its _________. - ANSWER Luminosity
According to the inverse square law of light, how will the apparent brightness of an
object change if its distance to us triples? - ANSWER Its apparent brightness will
decrease by a factor of 9.
If star A is closer to us than star B, then Star A's parallax angle is _________. -
ANSWER larger
Star A has an apparent magnitude of 3 and star B has an apparent magnitude of 5.
Which star is brighter in our sky? - ANSWER A
Which of the following terms is given to a pair of stars that we can determine are
orbiting each other only by measuring their periodic Doppler shifts? - ANSWER
spectroscopic binary
What can we infer, at least roughly, from a star's luminosity class? - ANSWER its size
(radius)
the remains of a star that ran out of fuel for nuclear fusion - ANSWER White Dwarf
It is the spectral type of the hottest main sequence star in a star cluster, and it tells us
the cluster's age. - ANSWER main-sequence turnoff point
All stars are born with the same basic composition, yet stars can look quite different
from one another. Which two factors primarily determine the characteristics of a star? -
ANSWER Mass and stage in life
1/parallax angle (arcsecond) - ANSWER distance (parsecs)
the magnitude it would have if it were a distance of 10 parsecs (32.6 light-years) away -
ANSWER Absolute magnitude
To calculate the masses of stars in a binary system, we must measure their _________
and_________. - ANSWER orbital period and average orbital distance
Before we can use parallax to measure the distance to a nearby star, we first need to
know __________. - ANSWER the Earth-Sun distance
AND ANSWERS 100% CORRECT!!
, The total amount of power (in watts, for example) that a star radiates into space is
called its _________. - ANSWER Luminosity
According to the inverse square law of light, how will the apparent brightness of an
object change if its distance to us triples? - ANSWER Its apparent brightness will
decrease by a factor of 9.
If star A is closer to us than star B, then Star A's parallax angle is _________. -
ANSWER larger
Star A has an apparent magnitude of 3 and star B has an apparent magnitude of 5.
Which star is brighter in our sky? - ANSWER A
Which of the following terms is given to a pair of stars that we can determine are
orbiting each other only by measuring their periodic Doppler shifts? - ANSWER
spectroscopic binary
What can we infer, at least roughly, from a star's luminosity class? - ANSWER its size
(radius)
the remains of a star that ran out of fuel for nuclear fusion - ANSWER White Dwarf
It is the spectral type of the hottest main sequence star in a star cluster, and it tells us
the cluster's age. - ANSWER main-sequence turnoff point
All stars are born with the same basic composition, yet stars can look quite different
from one another. Which two factors primarily determine the characteristics of a star? -
ANSWER Mass and stage in life
1/parallax angle (arcsecond) - ANSWER distance (parsecs)
the magnitude it would have if it were a distance of 10 parsecs (32.6 light-years) away -
ANSWER Absolute magnitude
To calculate the masses of stars in a binary system, we must measure their _________
and_________. - ANSWER orbital period and average orbital distance
Before we can use parallax to measure the distance to a nearby star, we first need to
know __________. - ANSWER the Earth-Sun distance
