Astronomy Exam 4

Front 1

Hipparchus used triangulation to estimate the distance to the moon

Back 1

True

Front 2

The process by which a spinning object collapses and spins faster is called _____.

Back 2

conservation of angular momentum

Front 3

The brightness of a star at 10 parsecs is called the star's ______.

Back 3

absolute magnitude

Front 4

The shift of light toward the red end of the spectrum when it is near a black hole is caused by _____.

Back 4

gravitational redshift

Front 5

Apparent double stars are two stars going around each other.

Back 5

False

Front 6

This type of cluster has upwards of 1 million stars:

Back 6

Global Cluster

Front 7

Type II supernovas are white dwarf explosions.

Back 7

False

Front 8

A neutron star is typically about ____ across.

Back 8

16 km

Front 9

The star temperature classification that is just cooler than the sun is the F star.

Back 9

False

Front 10

This type of binary star system is detected by using the Doppler shift:

Back 10

spectral binary

Front 11

Binary stars are used to measure _____.

Back 11

Mass

Front 12

As core helium builds up it pushes the hydrogen into a _______.

Back 12

Shell

Front 13

One of the best candidates for a black hole is Cygnus X-1.

Back 13

True

Front 14

Using the period of bright stars and the standard candle formula you can measure distances to galaxies at the edge of the universe.

Back 14

False

Front 15

A white dwarf can explode from low point to low point in its cycle takes about ______.

Back 15

11 yrs

Front 16

The ______ is the point between two stars that they revolve around.

Back 16

center of mass

Front 17

Stars that are forming are called ______.

Back 17

Protostars

Front 18

Sunspots appear dark because …..

Back 18

they are cooler than the surrounding surface of the Sun.

Front 19

The Sun will ascend into the giant region of the HR diagram…

Back 19

twice

Front 20

In E=mc2 -c stands for _____.

Back 20

Speed of light

Front 21

A plot of temperature vs. luminosity for stars is known as the ______.

Back 21

HR diagram

Front 22

New interferometry techniques have measured many sizes of stars far from Earth.

Back 22

False

Front 23

A singularity is the collapse of a black hole to a point.

Back 23

True

Front 24

The stars with the shortest main sequence lifetimes will be…

Back 24

the highest mass

Front 25

The technique of combining the light from two or more smaller telescopes to obtain an image that is equivalent to that of a much larger telescope is called …

Back 25

interferometry

Front 26

The three-step process that creates energy in the sun is called the helium helium chain.

Back 26

False

Front 27

The Earth's history shows temperature has remained stable due to constant increases in greenhouses gases.

Back 27

False

Front 28

A supernova type ___ is from a white dwarf explosion.

Back 28

Ia

Front 29

Stars whose absorption lines move back and forth are called ______.

Back 29

Spectroscopic binaries

Front 30

M stars have a surface temperature of about __________.

Back 30

3000 K

Front 31

The Balmer lines in a spectrum are the signature of

Back 31

hydrogen

Front 32

This part of the sun's atmosphere is at a temperature about 1,000,000 K:

Back 32

corona

Front 33

Very massive stars live relatively short lives.

Back 33

True

Front 34

When electrons are forced very close together, they can stop collapse of a star. This is known as ________.

Back 34

Electron degeneracy

Front 35

The production of heavy atoms from light atoms inside of a star is called ___.

Back 35

Nucleosynthesis

Front 36

The process that generates energy in a white dwarf is

Back 36

nonexistent. A white dwarf no longer generates energy.

Front 37

Most stars are not on the main sequence.

Back 37

False

Front 38

A group of stars that is few hundred light years across and contains about 100 stars is likely a ______.

Back 38

Stellar association

Front 39

A white dwarf can explode in a supernova if it

Back 39

acquires enough extra mass.

Front 40

The study of waves inside the sun is called _____.

Back 40

Solar seismology

Front 41

The lower limit for a normal star is about .1 solar masses.

Back 41

True

Front 42

The core of the sun moves energy primarily by convection.

Back 42

False

Front 43

_____ of stars will lie on the main sequence.

Back 43

90%

Front 44

If you know a star's temperature and use the Stefan-Boltzmann law you can find ______.

Back 44

Luminosity

Front 45

the sun is expected to live about ____ years. …

Back 45

10 billion

Front 46

Absolute magnitude is the brightness of a star in the night sky.

Back 46

False

Front 47

Charges accelerating along a magnetic field give off _______.

Back 47

synchrotron radiation

Front 48

Star A has an apparent magnitude of 5. Star B has an apparent magnitude of 3.

Back 48

Answer = Star B is 6.310 times brighter than star A.

Front 49

The proper sequence of stages in the life of a star is…

Back 49

protostar, main sequence, red giant.

Front 50

Eclipsing binaries cannot be used to measure masses of stars.

Back 50

FALSE

Front 51

Stars like our sun will in their final phases become….

Back 51

Mira variable

Front 52

A low mass star is usually less than 12 solar masses.

Back 52

FALSE

Front 53

Luminosity is expressed as watts or wattage.

Back 53

TRUE

Front 54

When looking at stars, the brightest are the easiest to study. This is called …

Back 54

selection effect

Front 55

A main sequence star has a luminosity class of

Back 55

A … V

Front 56

Sunspots are a ________ storm on the sun.

Back 56

magnetic

Front 57

The curvature of space under general relativity can be caused by _____.

Back 57

Mass

Front 58

A cloud of ejected gas surrounding a dying star is called a ______.

Back 58

Planetary nebula

Front 59

Cepheid's have pulsation periods in the range of _____.

Back 59

1-70 days

Front 60

A flare is exactly the same as a sunspot.

Back 60

False

Front 61

A good analogy for magnetic waves in the solar atmosphere is similar to cracking a whip.

Back 61

True

Front 62

Helium core fusion in the Sun will last about _____ years.

Back 62

100 million

Front 63

Stars with a core temperature in excess of 20 million K probably have this hydrogen fusion type:

Back 63

CNO

Front 64

Using the Stefan-Boltzman law to find luminosity requires _______.

Back 64

Radius and temperature

Front 65

The baseline used in measuring the parallax of stars is….

Back 65

2AU

Front 66

As the sun's core heats up, the helium will begin to fuse in a process called __________.

Back 66

Triple alpha fusion

Front 67

Small dark areas in gas clouds that may be prime stellar formation areas are called ______.

Back 67

Bok Globules

Front 68

Mira variables have a period of about a day.

Back 68

False

Front 69

A recurrent nova is usually in a binary star system.

Back 69

True

Front 70

The hotter the star, the bluer it is. This is a consequence of _______.

Back 70

Wien's Law

Front 71

Eventually a white dwarf cools to a black dwarf.

Back 71

True

Front 72

Our sun will die as a white dwarf.

Back 72

True

Front 73

An O star is about _______ degrees surface temperature.

Back 73

30,000 K

Front 74

The sunspot cycle going from low point to low point in its cycle takes about ______

Back 74

11 years

Front 75

When a new star ejects gas in opposite directions, this is known as _______

Back 75

bipolar flow

Front 76

This is an almost massless particle that is produced in fusion:

Back 76

neutrino

Front 77

Huge plumes in the lower chromosphere of the sun following magnetic lines are called _____

Back 77

prominences

Front 78

The Sun's source of energy is

Back 78

fusion of hydrogen into helium

Front 79

Particles that exist in tiny energy fluctuations and are then gone are called _____

Back 79

. virtual particles

Front 80

Stars like our sun will leave this type of remnant after they die:

Back 80

white dwarf

Front 81

The motion along the line of sight is commonly called _____.

Back 81

Radial motion

Front 82

Large massive stars create a series of nested shells of fusion as they age.

Back 82

true

Front 83

The sun will become a supernova.

Back 83

False

Front 84

A star's first energy source comes from gravitational collapse.

Back 84

True

Front 85

The force that holds the nucleus of the atom together is called the _____.

Back 85

Nuclear force

Front 86

The Pleiades are most likely an open cluster.

Back 86

True

Front 87

Our sun is a G star.

Back 87

True

Front 88

Granulation on the Sun is evidence of

Back 88

convection in the photosphere

Front 89

The nearest star to the Earth is Proxima Centauri.

Back 89

True

Front 90

__________ are small bright dead cores of stars like our sun.

Back 90

White dwarfs

Front 91

Stellar computer models help us trace a star's life from birth to death.

Back 91

True

Front 92

If the Sun were to become a black hole, the Earth and other planets would

Back 92

Continue Orbiting as they do now

Front 93

Mira variable stars change their brightness by

Back 93

Molecules in cool atmosphere

Front 94

The Earth-sun distance is known as a(an) ______.

Back 94

Astronomical Unit

Front 95

Stars that pulsate in and out are called ______.

Back 95

Variable Stars

Front 96

Stars with less than about 0.4 times the mass of the Sun are probably

Back 96

fully Convective

Front 97

A technique to find diameters of stars using short exposures is called

Back 97

speckle interferometry.

Front 98

Cosmic rays are fast moving particles in space.

Back 98

True

Front 99

The last fusion stage in a massive star is

Back 99

Silicon to iron

Front 100

The best place to find star formation is in a _____.

Back 100

molecular cloud

Front 101

The total amount of energy that a star emits is called its _______.

Back 101

luminosity

Front 102

The layer in a variable that star that is responsible for alternately absorbing and releasing the energy flowing from the center of the star is made up of ___________.

Back 102

Partially ionized helium

Front 103

The age of a star cluster can be determined by its turnoff point.

Back 103

True

Front 104

Star clusters provide a way to test stellar evolution theory because

Back 104

all the stars in a cluster are the same age and come in many different types.

Front 105

The person who first started the magnitude scale for stars was _____.

Back 105

Hipparchus

Front 106

High mass stars are those above ___ solar masses.

Back 106

8

Front 107

We use this to help measure the distance to variable stars:

Back 107

period luminosity

Front 108

The Chandrasekhar Limit is about:

Back 108

1.4 times the mass of the Sun

Front 109

40% of visible stars are binary systems:

Back 109

True

Front 110

Some neutron stars have periods in milliseconds:

Back 110

True