The Second Celebration of Knowledge

Question 1

imagine taking a census of the stars in our galaxy that are near to the sun. what types of stars are you most likely to find?

Answer 1

those with low luminosity and low temperature

Question 2

when you look up at the stars, what stars can you see with your naked eye?

Answer 2

the ones that have a high luminosity that are far away

Question 3

You apply the technique of spectroscopic parallax to determine the distance to a an A0V star having an apparent magnitude of 8.0. Later you realize that you made a mistake in determining the spectral type of the star and you find out the star is actually spectral type K5V. How does this change the distance you estimated?

Answer 3

The distance to the star is less than before.

Question 4

what are the two properties that determine how long a star will live on the main sequence?

Answer 4

1. mass (how much hydrogen it contains)

2. luminosity (the rate at which the hydrogen is burned

Question 5

compared to the sun, what happens to a star that is 10 x more massive than our sun

Answer 5

it burns the fuel 10,000 x faster, thus having a much shorter lifetime

Question 6

compared to the sun, what happens to a star that is 10 x less massive than our sun

Answer 6

it burns the fuel 100 x slower, thus having a much longer lifetime

Question 7

as luminosity and mass increase, what happens to the star?

Answer 7

it consumes more hydrogen, which then decreases the star’s lifetime

Question 8

as luminosity and mass decrease, what happens to the star?

Answer 8

its hydrogen consumption becomes more modest, thus increasing the star’s life

Question 9

what is the spectral order of the stars

Answer 9

O B A F G K M (oh boy, a fine girl, kiss me!)

Question 10

what is convection?

Answer 10

transport of thermal energy by the motion of a fluid (surface of the sun)

Question 11

what is radiation?

Answer 11

transport of thermal energy by radiant energy (middle region of the sun)

Question 12

what is the temperature for O-0?

Answer 12

40,000 K

Question 13

what is the temperature for B-0?

Answer 13

20,000 K

Question 14

what is the temperature for A-0?

Answer 14

10,000 K

Question 15

what is the temperature for F-0?

Answer 15

7,500 K

Question 16

what is the temperature for G-0?

Answer 16

5,500 K

Question 17

what is the temperature for K-0?

Answer 17

4,000 K

Question 18

what is the temperature for M-0?

Answer 18

3,000 K

Question 19

based on the ideal gas law, what happens when you increase the pressure of plasma

Answer 19

the temperature increases

Question 20

what are stars made of?

Answer 20

very hot hydrogen faith in an ionized state, aka plasma

Question 21

What is the Standard Solar Model (SSM)

Answer 21

a mathematical treatment of the sun as a giant ball of gas that predicts many of the intrinsic properties of the sun

Question 22

what about a star should a good SSM predict?

Answer 22

the mass, radius, age, luminosity, surface temperature, composite