chapter 8

Question 1

how do spectra help astronomers identify stars?

Answer 1

The astronomers observe the spectra of a star, to identify the elements in the star

Question 2

how do astronomers determine the distance that a star is from earth

Answer 2

By using principles of parallax

Question 3

what is a binary star system and why do they form

Answer 3

It is a system of two stars, orbiting, a Commons center of gravity, which holds each one and its orbit

Question 4

how do astronomers estimate how many stars are in the galaxy?

Answer 4

By observing a galaxy size brightness and mass

Question 5

Central bulge of star clusters, gas, and dust with cooler, older stars, more Central, and hot blue stars in the arms

Answer 5

Spiral galaxies

Question 6

No definite shape, little mass, a lot of gas, and new stars

Answer 6

Irregular galaxies

Question 7

Bright centers, very little gas, or dust, only has old stars

Answer 7

Elliptical galaxies

Question 8

The brightness of a star measured by an observer, who is a standard 32.6 light years away.

Answer 8

Absolute magnitude

Question 9

The brightness of an object, as it appears to an observer on earth

Answer 9

Apparent magnitude

Question 10

A pair of stars that orbit their common center of mass

Answer 10

Binary star system

Question 11

Massive celestial object with gravity, so strong that not even light can escape

Answer 11

Black hole

Question 12

The apparent shift in frequency of waves emitted by a moving source

Answer 12

Doppler effect

Question 13

Large systems of stars in their solar systems, gas, and dust held together by gravity

Answer 13

Galaxy

Question 14

apparent shift in an objects direction, viewed from two geographically distant locations

Answer 14

Parallax

Question 15

Spinning neutron star that gives off pulses of radiation at regular intervals

Answer 15

Pulsar

Question 16

Groups of stars that have a common origin and are held together by mutual gravitational attraction

Answer 16

Star cluster

Question 17

violent explosion of a star

Answer 17

Supernova

Question 18

True or false: stars give off light as a part of a nuclear fission reaction in which helium atoms are split into hydrogen atoms

Answer 18

False: stars are fueled by nuclear fusion in which two hydrogen atoms are fused into a helium atom

Question 19

True or false: before a star becomes a black hole, it explodes as a supernova

Answer 19

True

Question 20

True or false: blue stars are hotter than red stars

Answer 20

True

Question 21

True or false: some stars orbit, a neighboring star as a part of a binary star system

Answer 21

false: these stars orbit, their center of mass

Question 22

True or false: most galaxies are isolated out in space

Answer 22

false: most galaxies exist in clusters/superclusters

Question 23

True or false: the small number of supernova remnants in the universe, supports the big bang model

Answer 23

false: the small number of supernovas support the young universe worldviews

Question 24

True or false: when a stars mass is stabilized, the force of gravity maintains the stars size

Answer 24

True

Question 25

There is a balance between pressure and gravity in

Answer 25

Main sequence stars

Question 26

stars spend the majority of their life in what region of the HR diagram

Answer 26

Main sequence region

Question 27

what elements make up the greatest percent of most stars?

Answer 27

hydrogen

Question 28

What type of galaxy is the Milky Way galaxy?

Answer 28

spiral galaxy

Question 29

stars emit what two types of spectra

Answer 29

emission line spectra and absorption line spectra

Question 30

Most galaxies are what type of galaxy

Answer 30

Spiral

Question 31

In the 1880s, stars were classified according to what method

Answer 31

Spectra