Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

ASTRO 100 > Larissa 1 > Flashcards

Larissa 1 Flashcards

(72 cards)

Start Studying
1
Q

where does fusion occur?

A

only in the core, compression of outer layers allows the core to get hot enough for fusion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what are the three regions of the HR diagram?

A

main sequence
supergiants
white dwarves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is the observed relationship on the HR diagram?

A

massive stars tend to be more bright

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

why is it easier to measure the masses of binary stars?

A

due to their observed movement - orbiting a centre of mass

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what is more common, high mass or low mass stars?

A

low mass

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what is considered a high mass star

A

greater than 8 solar masses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

true or false, solar flares can be up to the size of earth

A

true

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what causes aurora?

A

solar flares
charged particles from the solar flare hit the earths atmosphere and we see more colours at the poles because the earths magnetic field attracts charged particles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what is a solar maximum?

A

when the sun has the most amount of activity e.g solar flares

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

which stars tend to be more active?

A

low mass stars

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what is hydrostatic equilibrium?

A

gravity acting towards the core is balanced by pressure produced from fusion acting outwards

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

when does a star leave hydrstatic equilibrium and what happens?

A

when they run out of H.
1. gravity inwards is greater than fusion outwards.
2. H shell formation
3. new source of outwards pressure and makes star bigger - red giant phase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

true or false, the sun will become a red giant

A

true, 100x bigger than current size
earth life wouldnt survive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what is a brown dwarf?

A

not enough material for fusion to start

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

why are white dwarves stable?

A

due to electron degeneracy pressure balancing gravity acting inwards and preventing collapse

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

a more massive star gives a _________ white dwarf

A

smaller

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

why can high mass stars fuse heavier elements than low mass stars?

A

because there is more mass weighing on the core

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

describe shell fusion in high mass stars

A

shell fusion with elements higher than H, and each new element fuses quicker than the previous

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

why does the fusing of elements stop at Fe in high mass stars?

A

because fusing Fe consumes energy and Fe has the highest binding energy (nuclei lighter than Fe release energy when fused, but nuclei heavier than Fe require energy to fuse)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what happens when a dying HMS tries to fuse Fe?

A

it consumes energy and causes the HMS to collapse in on itself and causes a core-collapse supernova

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

can supernovae be naked eye objects?

A

yes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what do supernovae remnants look like?

A

nebulae

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

how long does a LMS planetary nebula phase last?

A

billions of years

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

core collapse supernova plus protons and electrons combining into neutrons equals a?

A

neutron star

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
what happens if you get too close to a black hole?
extreme tidal forces causes spaghettification
26
describe the death of binary stars
more massive dies first and when it is a white dwarf, it can gain enough mass from the newly dying red giant to surpass the chandrasekhar limit and can cause a type 1A supernova
27
true or false, an atom is more empty than our solar system
true
28
astronomy involves how many different magnitudes of size?
50
29
describe the origin of elements and the big bang
10 sec to 20 mins first 10 sec too hot and blew atoms apart as the universe expanded
30
describe cosmic ray collisions
high energy particles that come from a cosmic source, hit earth atmosphere and cause a shower of secondary particles
31
which elements does cosmic ray collisions make
Be
32
describe dying stars planetary nebula
enriches universe through slow neutron capture (and release of an electron) - can happen because they are in this stage for ages
33
true or false, dying LMS can fuse heavier elements than dying HMS
true, because the planetary nebula phase gives the low mass stars more time to do slow neutron capture
34
describe dying high mass stars as the origins of the elements
core collapse supernova spews heavier elements into space. can also do slow neutron capture but can't fuse as heavy element as low mass stars
35
describe white dwarf supernova origin of elements
thermonuclear SN fuses as it explodes. A carbon oxygen core fuses and creates heavier elements in a few seconds
36
describe merging neutron stars
causes a kilonovae after exceeding their 3SM limit and does rapid neutron capture
37
how do neutron stars merge?
they begin to orbit due to their dips in space time, not due to gravity, and release gravitational waves as they do so which cause the system to lose energy, causing them to orbit closer together until they merge, causing rapid neutron capture. then no GW as no more movement
38
what is a common feature of man-made elements?
very short half lives
39
almost everything came from the death of a star in one way or another
true, apart from H and He from the big bang
40
why do objects in space all look similar?
all stuff in space was made from other space stuff
41
why do things orbit the sun in ellipses?
because of the centripetal force provided by the suns gravity balanced with the objects velocity
42
why do things orbit the sun in a flat disk
due to the conservation of angular momentum - makes things spin faster as it collapses and flattens them into a disk
43
what proves an interstellar object over a stellar object
hyperbolic orbits
44
comets look like?
KBOs
45
describe the not stationary sun
bow shock shape with the heliosphere long and in one direction due to the sun travelling
46
formation of stars and planets happens?
together within a molecular cloud (a cold clump of gas and dust)
47
why are molecular clouds cold?
so gravity can pull everything together and make a star (colder means less kinetic energy)
48
why do all planets spin the same direction (more or less)
due to the original spin of the molecular cloud
49
what is bennu?
an asteroid that proves solar nebula theory step 3- other gas and dust particles collide to form asteroids etc - loosely held together rock
50
what caused the moon's craters?
rocks smashing into it
51
how do we know the sun formed at the same time as the planets?
radiometric dating of oldest rocks in SS.
52
why do we have bigger planets in the outer ss?
1. due to them being past the frost line, so more solid objects, which is rqd for planet formation, and larger cores are able to form 2. larger cores can attract more gas and dust which is trapped due to higher escape velocity 3. colder outer ss means Vgas is smaller and easier to be captured
53
what is the nearest astronomical object?
the moon, at 384,000 kms away
54
what are the effect of the earths tidal forces on the moon?
earths gravity stretches the moon as is stronger due to earth having more gravity. - causes the moon to rotate slower, causing tidal locking
55
why does mars have a blue sunset?
its atmosphere preferentially scatters red light, and when the sun is setting, all the red light is scattered and gone, and we see blue.
56
where is the H2O on mars?
H2O ice under CO2 ice at the polar ice caps
57
brown dwarves are __-__ times the mass of jupiter
13 - 80
58
which is more dense, jupiter or saturn?
jupiter, and is far more massive than you would expect
59
what is the red spot?
a hydrogen storm that is earth sized
60
what makes moons of the outer ss active?
tidal heating
61
what are near earth objects?
they orbit the sun but are within 0.3 AU or 45 million km to earth
62
where did our water today come from?
90% from KBOs or oort cloud objects that hit our planet and melted
63
what evidence is there for a 9th planet
KBOs are aligned when they should be randomly distributed
64
what is saggitarius A?
black hole at the centre of the milky way
65
true or false, there is a centre of the universe
false, but there was a time where everything was at one point
66
why was hubble's constant originally wrong?
he was observing a different kind of cepheid variable with a different period-luminosity relationship
67
Hubbles constant doesn’t take into account ________?
changes in rate of universe expansion
68
what is the coincidence problem?
why do we live in an era where dark energy is starting to dominate?
69
what is the large scale structure of the universe?
the cosmic web
70
which galaxy type is most likely to have a central BH?
larger ones such as elliptical or spiral
71
why is andromeda blueshifted?
because its peculiar velocity is higher than the speed of universe expansion and swamps the redshift
72

ASTRO 100 (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions