Quiz 5

Question 1

An object in the process of becoming a star, before it reaches the main sequence is called a

Answer 1

protostar

Question 2

Singularity is also called a

Answer 2

black hole

Question 3

Reflection nebulae look ______ than the star whose light they are scattering

Answer 3

Bluer

Question 4

Dark nebulae are

Answer 4

clouds of dust and gas

Question 5

Interstellar extinction refers to

Answer 5

The absorption and scattering of starlight by the interstellar material

Question 6

A star like our sun takes about ______ years to form

Answer 6

30 million

Question 7

Polycyclic aromatic hydrocarbons

Answer 7

All of the above

• Are inorganic molecules found in interstellar dust
• are organic molecules found in the interstellar medium
• provide a tool to understanding the abundances of chemicals related to life
• are common in daily life

Question 8

Polycyclic aromatic hydrocarbons are inorganic

Answer 8

False

Question 9

A _____ nebula is a spherical shell of gas that is expelled by a low mass red giant near the end of its life

Answer 9

Planetary

Question 10

Astronomers estimate that 10% of all stars are ____ dwarfs.

Answer 10

White

Question 11

____ flash is the process of runaway helium fusion reactions that occurs during the evolution of a red giant

Answer 11

Helium

Question 12

As it evolves, the sun will go through the following stages:

Answer 12

Protostar
Main Sequence
Red Giant
Planetary Nebula
White Dwarf

Question 13

Compared to the main-sequence lifetime of our sun, the main sequence lifetime of a star that is twice as massive as the sun and 100 times as luminous is about

Answer 13

There is something wrong with the numbers given. This is impossible.

Question 14

Just after a low-mass star like our Sun exhausts the hydrogen in its core

Answer 14

The core contracts and the star’s outer layers expand

Question 15

A _____ star is a star that has collapsed to the point at which it is supported by neutron degeneracy.

Answer 15

Neutron

Question 16

In the densest interstellar cloud, the particles density is ________ the particle density of air at sea level on earth

Answer 16

Much less than

Question 17

The study of star clusters

Answer 17

All of the above

Question 18

The presence of an emission nebula suggests the presence of

Answer 18

Interstellar gas and a hot star

Question 19

The instability strip

Answer 19

is a region in the H-R diagram where pulsating stars are found

Question 20

When a star goes supernova and a neutron star is formed

Answer 20

all of the above

Question 21

An object shows large variations in its energy output (covering its entire surface) in a time period of about 30 microseconds. This implies that the source could be a

Answer 21

neutron star

Question 22

Type II supernovae are most likely the result of

Answer 22

the collapse of the iron core of a massive star

Question 23

Black holes are real

Answer 23

true

Question 24

An event horizon is the surface of the sphere around a black hole from which nothing can escape. It’s radius is the ________ radius.

Answer 24

Schwarzschild

Question 25

_____ in space accounts for 99% of the total mass of interstellar material.

Answer 25

Gas