Chapter 10 First Homework After Secnd Midterm

Question 1

An H-R diagram is a plot of which two stellar properties?

Answer 1

Luminosity (absolute magnitude)

Temperature (spectral class)

Question 2

Absolute magnitude is equivalent to what ?

Answer 2

A stars luminosity

Question 3

What is the absolute magnitude of the sun?

Answer 3

4.8

Question 4

Increasing the distance to a star by a factor of 10 decreases its apparent brightness by a factor of what?

Answer 4

100

Question 5

Apparent magnitude

Answer 5

A measure of brightness as it appears from earth

Question 6

Absolute magnitude

Answer 6

The brightness as seen at a distance of 10 parsecs

Question 7

For stars that are more than 10 pc from earth what is great the apparent magnitude of the absolute magnitude ?

Answer 7

Apparent

Question 8

For stars closer than 10 pc to earth what is great apparent magnitude or absolute magnitude ?

Answer 8

Absolute magnitude ?

Question 9

1 parsec is how many light years?

Answer 9

3.3 light years

Question 10

As distance increases

Answer 10

Parallax decreases

Question 11

The formula for a stars distance from the sun in relation to its parallax

Answer 11

Distance (in parsecs) = 1/ parallax (in arc seconds)

Question 12

A star with a parallax of 1 inch lies at what distance from the sun?

Answer 12

1 pc

Question 13

An object with a parallax of .5 is how far from the sun?

Answer 13

1/ .5 = 2 pc

Question 14

What is the closest star system to our sun and how far away is it ?

Answer 14

Alpha Centauri it has a parallax of .77 inch’s so 1.3 pc away

270,000 AU

4.3 light years

Question 15

How many stars are within 5 pc of our sun?

Answer 15

Less than 100