Chapter 9 Quiz

Question 1

What is Parallax?

Answer 1

The effect whereby the position of an object appears to differ when viewed from different positions. This is what is used to determine the distances to stars.

Question 2

How many light years is one parsec?

Answer 2

3.26LY = 1 Parsec

Question 3

What were the historical attempts to measure the distance to the stars?

Answer 3

1. Celestial Sphere
2. Tycho could not measure
3. Bessel (1838) made telescopic observations of 61 Cyg ~ 1” over 2 AU’s

Question 4

What were some modern methods to measure the distance to the stars?

Answer 4

1. Large telescopes
2. Photographic images
3. CCD images
4. Hipparcus Satellite
   a. Operated from 1989 to 1993 which ahs given
   estimates accurate to 5% for 7000 stars.
   We now have reliable estimates for stars within
   200 PC of the Sun.
   5.

Question 5

The motion relative to background stars that most stars exhibit is called ___.

Answer 5

Proper motion.

Question 6

Why do stars differ in apparent brightness?

Answer 6

Because stars have various intrinsic brightnesses and distances.

Question 7

What is apparent magnitude?

Answer 7

the defined visual scale for catalog going from numbers 1(brightest) to 9(dimest). In other words, the brightness of a star seen from the Earth.

Question 8

What is Absolute Magnitude?

Answer 8

The intrinsic measure of a star if it were 10 parsecs away

Question 9

What is apparent luminosity?

Answer 9

The apparent luminosity that is visible to the human eye

Question 10

what is Absolute Luminosity?

Answer 10

The intrinsic measure of energy given off by a star.

Question 11

what are the rough star distance estimates based on formulas that are good to know?

Answer 11

If m-M > 0, the star is more than 10 Parsecs away,

If m-M < 0, the star is more than 10 Parsecs away, and if m-m = 0, the star is 10 parsecs away.

Question 12

What were Father Secchi’s astronomical contributions?

Answer 12

He collected Spectra from various stars.

Question 13

What were Bohr’s Astronomical contributions?

Answer 13

1. He developed a model for atoms

2. He developed a model to explain how light is produced by atoms.

Question 14

What were Cannon’s astronomical contributions?

Answer 14

She surveyed many spectra from stars and categorized them.

Question 15

Must stars have an absorption Spectra, what are the broad classes of these?

Answer 15

O B A F G K M with subclasses of 0-9

Question 16

What spectra classification is the sun?

Answer 16

G2

Question 17

Why do stars have different spectra?

Answer 17

Main Reason: 
     1. The physical condition of the atoms
Minor Reasons: 
     1. Different chemical abundances
     2. Steller ages.

Question 18

What are balmer lines?

Answer 18

Balmer lines are lines in a spectra that are seen when electrons are past the first orbit in a specific sweet spot orbit. If they pass this sweet spot, the lines will start to fade(This is affected by temperature and the organization of atoms).

Question 19

What is the Hertzsprung-Russel diagram?

Answer 19

The Hertzsprung-Russel diagram is a series of clusters categorized into specific types of stars, with each star in a specific cluster being the same distance away from the Sun as all the others in its specific cluster.

Question 20

What types of stars are there in the Hertzsprung-Russel diagram?

Answer 20

1. Main Sequence stars: The stars in the main sequence vary, but follow the same pattern. Hot stars are the brightest, while cold stars are the dimmest. Main sequence stars make up 90% of them all.
2. Giants: Very bright but cool stars compared to the main sequence stars. (main sequence stars often turn into these as they age.)
3. White Dwarfs: Very hot but dim stars when compared to main-sequence stars. (These are very old stars).
4. Supergiants: Extremely rare stars that are incredibly luminous compared to the Main sequence stars.

Question 21

In a Russel graph, stars that are cooler have a ___ number, are associated with ___, and are on the ___ axis.

Answer 21

higher, red, x.

Question 22

In a Russel graph, stars that are hotter have a ___ number, are associated with ___ and are on the ___ axis.

Answer 22

lower, blue, x.

Question 23

In a Russel graph, stars that are brighter have a ___ number, and are on the ___ axis.

Answer 23

lower, y.

Question 24

In a Russel graph, stars that are dimmer have a ___ number, and are on the ___ axis.

Answer 24

higher, y.

Question 25

What is Stephen Boltzman’s law?

Answer 25

The Stefan–Boltzmann law describes the power radiated from a black body in terms of its temperature.