Astronomy 101 Exam 5 questions and Verified
Answers
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
apparent shift caused by a change in the way you are looking at an object, not an actual motion
- ANSWER parallax
stars are different from the sun in ________, __________,__________, _________ - ANSWER
Age, size luminosity, brightness
3 most fundamental properties of starts - ANSWER luminosity, surface temperature, mass
how bright stars look in sky - ANSWER Apparent brightness
how bright stars are in absolute sense - ANSWER Luminosity
brightest stars are______
second brightest are _______ - ANSWER first magnitude, second magnitude
________ magnitude means ___________stars - ANSWER Larger, dimmer OR
smaller, brighter
determine surface temperature from - ANSWER color or spectrum
Answers
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
apparent shift caused by a change in the way you are looking at an object, not an actual motion
- ANSWER parallax
stars are different from the sun in ________, __________,__________, _________ - ANSWER
Age, size luminosity, brightness
3 most fundamental properties of starts - ANSWER luminosity, surface temperature, mass
how bright stars look in sky - ANSWER Apparent brightness
how bright stars are in absolute sense - ANSWER Luminosity
brightest stars are______
second brightest are _______ - ANSWER first magnitude, second magnitude
________ magnitude means ___________stars - ANSWER Larger, dimmer OR
smaller, brighter
determine surface temperature from - ANSWER color or spectrum
