Exam 3

Question 1

Photosphere

Answer 1

The surface of a star, where the plasma is thin enough that light can escape freely into space

Question 2

Corona

Answer 2

A stars upper atmosphere, where thin plasma is heated to millions of Kelvin by the stars magnetic field

Question 3

Fusion

Answer 3

The process where small nuclei are merged to form a heavier element, which can release energy

Question 4

Envelope

Answer 4

The interior part of a star where fusion doesn’t occur and where the composition stays the same since the star was formed

Question 5

Fission

Answer 5

When a heavy unstable nucleus breaks apart to form nuclei of lighter elements, which can release energy

Question 6

Core

Answer 6

The part of the star where energy is generated

Question 7

The sun shines because it is

Answer 7

Hot like a stove

Question 8

Heat is generated in the suns core by

Answer 8

Nuclear fusion of hydrogen into helium

Question 9

Nuclear ____ involves merging atoms while nuclear ____ involves splitting them

Answer 9

Fusion= merge
Fission= split

Question 10

The sun has been shining for __ years and is..

Answer 10

4.5 billion years; halfway through its life

Question 11

Sometimes the sun throws a ball of plasma and magnetic field out into the solar system. This is called a

Answer 11

Coronal mass ejection (CME)

Question 12

What causes sunspots and solar cycles

Answer 12

The suns magnetic field reverses polarity

Fusion powers the core, changes on the surface are c if the magnetic field

Question 13

There are more sunspots, flares, and CMEs during

Answer 13

The middle of a sunspot cycle

Question 14

Th corona glows in X-rays while the photosphere only glows in visible light, so we know the corona is ___ than the photosphere

Answer 14

Hotter

Question 15

The ___ is heated by fusion while the ___ is heated by magnetic fields

Answer 15

Core= fusion
Corona= magnetic fields

Question 16

If you were to dive into the sun, you would hit a solid surface at the..

Answer 16

… actually, the plasma would just get thicker and thicker as you fell in

Question 17

You can tell the temperature of a star by looking at its

Answer 17

Color

Question 18

Lost the spectral types from hottest to coolest

Answer 18

OBAFGKM

Question 19

How would you tell a K type red giant from a K type red dwarf?

Answer 19

The giant is more luminous

Question 20

True or false: as a star loses mass due to the stellar wind, it goes from being a main sequence O star to being a main sequence G star to finally being a main sequence M star

Answer 20

False; a star lands somewhere on the main sequence depending on its mass, and doesn’t move from there until it leaves the main sequence entirely

Question 21

On the main sequence compared to low mass stars, high mass stars are hotter

Answer 21

More luminous, and have shorter lifetimes

Question 22

High mass stars can fuse carbon but the sun cannot because

Answer 22

It’s core is not hot enough

Question 23

Stars on the main sequence range in luminosity and temperature, but they are all

Answer 23

Fusing hydrogen into helium in their cores

Question 24

Stars become larger once they leave the main sequence because

Answer 24

They are producing more energy, which makes the surface expand more

Question 25

List stellar corpses based on the mass of the star that formed from the lowest to the highest

Answer 25

White dwarf, neutron star, black hole

Question 26

When stars become red giants or red supergiants, they turn red because

Answer 26

The surface is farther from the center of the star

Question 27

Which kind of star will die by going supernova?

Answer 27

A star with more mass than our sun

Question 28

You see a bright star in the night sky. You have enough information to determine:

Answer 28

Nothing

Question 29

When a large gas cloud has clumps that form stars, you would tend to find

Answer 29

More low mass stars like K and M stars

Question 30

2 stars are the same mass. Star A is fusing hydrogen into helium, star B is fusing hydrogen into helium and helium into carbon and oxygen. Which star is older?

Answer 30

B; it’s fusing heavier elements

Question 31

List the stages that a low mass star goes through in chronological order

Answer 31

Main sequence, red giant, planetary nebula, white dwarf

Question 32

As a red isn’t the sun will fuse hydrogen in a shell around the core. What phase comes after this?

Answer 32

The sun fuses helium in the core and hydrogen in a shell around the core

Question 33

How can you measure the age of a star cluster?

Answer 33

Determine what mass the star is just about to leave the main sequence

Question 34

Your friend says, “this thing keeps publishing bright faint bright faint, and is giving me a headache.” What object is this?

Answer 34

Neutron star

Question 35

A supernova is when

Answer 35

A massive star dies, a white dwarf gains too much mass

Question 36

Parallax allows us to measure a stars

Answer 36

Distance

Question 37

You measure the pulsation period of a variable star in a star cluster. You can now estimate the?

Answer 37

Clusters distance

Question 38

Over its lifetime and death, a star creates ___ heavier elements than it uses, so it ___ the amount of heavy elements present in a galaxy’s gas

Answer 38

More, increases

Question 39

You observe a red supergiant and a red giant. Which is more polluted with heavier elements?

Answer 39

Red supergiant

Question 40

A habitable planet is one that

Answer 40

Is the right temperature for water to be liquid

Question 41

Why are exoplanets difficult to detect?

Answer 41

They’re far from earth, net to bright stars, and dim

Question 42

When we observe an exoplanet using the Doppler shift, the planets signal is

Answer 42

.. actually, we never see the planet itself

Question 43

A hot Jupiter exoplanet is a Jovian planet that

Answer 43

Is in very small orbit

Question 44

You see a star moving toward and away from you in a periodic manner. Which detection method is this?

Answer 44

Radial velocity

Question 45

Most of the planets in the exoplanet database are Jovian planets because

Answer 45

Our detection methods are biased toward finding Jovian planets

Question 46

The Drake equation allows us to estimate there are __ alien civilizations whose radio signals we could detect in the Milky Way

Answer 46

.. actually, we have no idea how many

Question 47

If you want to detect a planet like earth that is orbiting a star, you should observe it for a minimum of..

Answer 47

3 years