An Introduction To The Stars

Front 1

What does the gravity of Jupiter effect?

Back 1

1. motion of Mars
2. asteroids may collide with planets

but since individual stars are separated by huge distances and do not interact with one another

Front 2

How do stars move in the milky way?

Back 2

combined gravitational influence of all the other stars

Front 3

Motion of individual stars

Back 3

1. slowly changing positions, SIDEWAY MOTIONS
2. Doppler shift to measure radial velocities

Front 4

How do single star live it's life?

Back 4

quiet isolation

Front 5

From patters of motions of other stars we can..

Back 5

conclude that sun is travelling at 30km/sec in the solar neighbourhood

Front 6

What do the stars differ by?

Back 6

apparent brightness, need to determine distances

Front 7

How do we describe the brightness of the star?

Back 7

scale of magnitudes

Front 8

magnitude of scales

Back 8

1. fainter stars have numerically larger magnitudes
2. magnitudes can be negative or positive
3. nothing special about magnitude of 0

Front 9

Stars have different colours, which means..

Back 9

they produce different proportions of red and blue light

Front 10

Cool star

Back 10

produces mostly red light

Front 11

A hotter star produces

Back 11

more light overall but the balance would shift towards the blue

Front 12

What is the colour of a star a good indicator of?

Back 12

temperature

Front 13

What can affect the colour of a star?

Back 13

intervening gas and dust
-interstellar material

Front 14

Pattern of absorption lines..

Back 14

tells you the truth about the temperature
-because the star will look fainter than expected if affected by dust and gas

Front 15

What exactly does isolation imply?

Back 15

-an orbit whose shape is determined by the combined gravitational influence of all the other stars
-as the sun moves, it never comes close enough to other stars that they ,individual objects, influence us in any way

Front 16

Individual stars nearest to Solar System..

Back 16

HAVE SOME effect on us

Front 17

Light year

Back 17

the distance light travels in a year

Front 18

Stars have two motions..

Back 18

1. Ordered
2. Random

Front 19

distance

Back 19

ESSENTIAL, to say anything of real physical interest

Front 20

brightness

Back 20

both apparent and absolute
-measure how much energy is being received here on Earth from each star (apparent)
-THIS IS TO WORK OUT HOW MUCH ENERGY THE STAR PUMPS OUT IN TOTAL

Front 21

temperature

Back 21

red stars are cooler then blue stars

Front 22

entire spectrum

Back 22

how much light is given out AT EACH wavelength

Front 23

motions of the stars

Back 23

1. sideways (transverse) motion result in apparent stellar positions
2. radial (towards-or-away) motions measured from Doppler shift of the absorption lines in the spectrum

Front 24

masses

Back 24

need to find "test particle" whose motion is influenced by the star

Front 25

size and shape

Back 25

of the star need to be determined

Front 26

rotation rate

Back 26

deduced from the spectrum by an analysis of the widths of absorption lines in it's spectrum

Front 27

average density

Back 27

determined from it's mass and it's size

Front 28

composition

Back 28

study of it's spectrum

Front 29

internal structure

Back 29

knowledge of physics of atoms

Front 30

energy sources

Back 30

within the star itself, what keeps it hot

Front 31

Is it active?

Back 31

does it flare up? as an example

Front 32

How an if it is changing?

Back 32

at present as it slowly uses it's fuel

Front 33

What we need to know about the stars lastly?

Back 33

1. how it will end up
2. it's age
3. how it formed

Front 34

True motion of the stars

Back 34

carries it partly along our line of sight(radial velocity) and partly across it (transverse velocity)

Front 35

Proper motion

Back 35

a change in the direction in which we see the star, relative to its neighbours

Front 36

Which star has the largest proper motion?

Back 36

Bernards star

Front 37

Stellar paradox

Back 37

if all stars moved an approximately equal speeds, the ones which are closest seem to change position most quickly

Front 38

How to determine where the sun itself is going

Back 38

1.positon
2. velocity

Front 39

Peculiar velocity

Back 39

-the suns owns speed, causing it to pass through the general distribution of the nearby stars

Front 40

More-or-less in parallel

Back 40

stars movement

Front 41

solar apex

Back 41

absorption lines in the spectra of the stars are Doppler-shifted to shorter wavelengths, indicating catching up to those stars

Front 42

solar antapex

Back 42

average velocity of the stars is a bit positive, that is the distance between us and them is increasing as slowly leave them behind

Front 43

In what direction is the sun moving?

Back 43

star VEGA

Front 44

First magnitude

Back 44

the brightest stars

Front 45

Magnitude of the full moon and sun?

Back 45

-10 for the full moon and -26 for the sun

Front 46

Ratios of brightness is measured where?

Back 46

magnitude scale (logarithmic scale)

Front 47

For every 5 magnitudes difference, that represents..

Back 47

brightness factor of a factor of 100

Front 48

What is beneficial about magnitude scale?

Back 48

-cover a very great range of values
-DYNAMIC RANGE

Front 49

Distance does not matter in colour of the star, why?

Back 49

all photos travel unimpeded through empty spac and their relative numbers, the ratio of the numbers of blue and red photons, and this the colour of the light will not change

Front 50

Why does the sun look red at sunset, is it because it is cooling down?

Back 50

NO, because we are seeing it low in the sky