Astronomy Unit 7

Question 1

_____ is the point where gravity compresses an object to infinite density and to almost no volume.

Answer 1

Singularity

Question 2

invented the spectroscope

Answer 2

Joseph Von Fraunhofer

Question 3

plotted the absolute magnitude of stars against their spectral classes

Answer 3

Henry Russel

Question 4

occurs when a star’s iron heart suddenly compresses its mass in tenths of a second from stellar death

Answer 4

Big Scrunch

Question 5

plotted the absolute magnitude of individual stars within clusters against their colors

Answer 5

Enjar Herzsprung

Question 6

a chart of the absolute magnitudes of stars plotted against their temperatures

Answer 6

H-R Diagram

Question 7

A _____ is two stars orbiting a common center of gravity.

Answer 7

Binary Star

Question 8

A _____ is when both stars in a system can be seen separately through a telescope.

Answer 8

Visual Binary

Question 9

The _____ cycle/process only occurs in really hot stars.

Answer 9

triple-alpha

Question 10

Stars toward the _____ of the main sequence fuse hydrogen at a slower rate because they have less internal nuclear activity.

Answer 10

lower right

Question 11

A red variable is a _____ star that is a red giant or supergiant.

Answer 11

long-term variable

Question 12

indicated by adding a Roman numeral to the letter and number that designates a star’s class

Answer 12

luminosity

Question 13

a unit of distance equal to 3.0857 × 1013 km

Answer 13

parsec

Question 14

approximately 9,460,000,000,000 km

Answer 14

light-year

Question 15

the center curving line in the H-R diagram

Answer 15

main sequence

Question 16

plotted to the upper right on the H-R diagram

Answer 16

giants and supergiants

Question 17

Which of the following sentences best describes our Sun?

Answer 17

Our Sun is a G2 yellow star of above-average size.

Question 18

Main-sequence stars are all designated by luminosity class _____.

Answer 18

v

Question 19

_____ measures the total energy output of a star.

Answer 19

absolute magnitude

Question 20

_____ is a term describing fluids at rest.

Answer 20

Hydrostatic equilibrium

Question 21

occurs after helium begins to fuse with carbon in the triple-alpha process

Answer 21

“helium flash”

Question 22

a form of degenerate matter that can occur after a star explodes

Answer 22

a black hole or neutron star

Question 23

keeps helium from accumulating in the core of a red dwarf

Answer 23

convection

Question 24

the exponent to which a base must be raised to produce a given number

Answer 24

logarithm

Question 25

a form of an element having the same number of protons, but having more or fewer than the usual number of neutrons

Answer 25

isotope

Question 26

A star leaves the main sequence when it stops fusing hydrogen into _____ in its core.

Answer 26

helium

Question 27

The _____ cycle process ends with the production of helium-4.

Answer 27

hydrogen helium

Question 28

_____ dictates what characteristics a star shows throughout all stages of its activity.

Answer 28

mass

Question 29

_____ spectra indicate the presence of specific elements because those elements absorb white light.

Answer 29

dark-line

Question 30

_____ spectra indicate the presence of specific elements and confirm the heat necessary to vaporize them.

Answer 30

bright-line

Question 31

Formation of _____ marks the end of a blue star’s life because it cannot be fused into another element.

Answer 31

iron

Question 32

The _____ permits light only from a selected source.

Answer 32

slit

Question 33

_____ do not shrink further because their electrons cannot get any closer together.

Answer 33

white dwarfs

Question 34

_____ spin rapidly because they are governed by the spin rate of their original star being concentrated into a drastically shrunken condition.

Answer 34

pulsars

Question 35

The _____ cycle/process begins and ends with the same element.

Answer 35

carbon

Question 36

Almost everything we know about stars comes to us through careful analysis of the _____ they emit.

Answer 36

light

Question 37

A(n) _____ is a star that suddenly flares up, then fades after a few weeks or months.

Answer 37

nova

Question 38

A _____ is a neutron star that emits narrow beams of energy as it spins on its axis.

Answer 38

pulsar

Question 39

_____ is how bright a star looks in our sky.

Answer 39

Apparent magnitude

Question 40

As a white dwarf cools, the carbon and oxygen ions lock themselves into a crystal _____, or three-dimensional pattern of atoms.

Answer 40

lattice