Stars Flashcards

(57 cards)

1
Q

more massive stars, due to greater gravity, are..?

A

squeezed into smaller, more densely packed objects than less massive stars

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

hottest, brightest and more massive stars

A

Blue stars

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

90% of the stairs

A

Main sequence stars

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

stars exceeding eight solar masses, with short life spans

A

High-Mass Stars

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

Stellar Evolution of Medium-mass (sun-like) stars

A

Nebular > protostar > main-sequence > red giant > planetary nebula > white dwarf

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

Red Giant Stage

A

begins when the hydrogen is consumed, leaving a helium-rich core > core no longer has the gas pressure that resist the inward pull of gravity > core contracts, temperature increase > expansion of the star > as the star expands, its surface cools (red) > eventually the star’s gravity stops expansion > gravity and gas pressure, again achieve balance > star enters a stable state, but is much larger > astonishing increase in temperature, converts helium into carbon and oxygen

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

largest white dwarfs = ?

A

least massive

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

smaller and more massive than white dwarfs

A

Neutron Stars

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

“average star”

A

Sun

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

radiates short pulses of radio energy named pulsar (pulsating radio source)

A

Neutron Stars

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

without fuel ->no balance between gas pressure and gravity > it collapses > enormous implosion resulting in a shock wave > this energetic shock wave blasts the star’s outer shell into space generating ..

A

SUPERNOVA

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

terminate in brilliant explosions (supernova)
*during supernova, these stars become millions of times brighter

A

High-mass stars

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

terminate in brilliant explosions (supernova)
*during supernova, these stars become millions of times brighter

A

High-mass stars

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

*much fainter and smaller than the main-sequence stars of the same temperature
*some are almost the same size of Earth

A

White Dwarfs

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

form if the core of a remaining star exceeds the three solar mass limit (neutrons can withstand the gravity)

A

Blackhole

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

90% of star-life

A

Main-sequence stage

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

some red giants alternately contract and expand

A

variable stars

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

Hertzsprung-Russell Diagram

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

Protostar Stage

A

gravitational contraction continues rapidly > core heats much faster > temperature: 10 million K > start to initiate nuclear fusion (hydrogen fusion) > will reach a point wherein inward pull of gravity will be balanced by temperature of hydrogen fusion

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

with masses ranging between 1/2 and eight times that of the Sun

A

Medium-Mass Stars

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

Stellar Evolution of Massive Stars

A

Nebula > protostar > main sequence (blue) > Red supergiants > supernova explosion > neutron star or blackhole

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

spirals around a “void”

A

accretion disk

24
Q

main sequence = ?

25
electrons are displaced inward from their regular orbits around an atom’s nucleus
Degenerate matter
26
Why is it called protostar?
heat is not enough to initiate nuclear fusion (source of energy)
27
coolest, dimmest and less massive stars
Red stars
28
without sources of energy, white dwarfs..
slowly cool and dim
29
never become bloated red giants and remain a stable main-sequence star until they ran out of hydrogen fuel and collapse into a white dwarf
Low-mass stars
30
first black hole to be discovered
Cygnus X-1
31
Stellar Remnant
\* white dwarf \* neutron star \* black hole
32
found in the center of galaxies are estimated to be millions of solar masses
Larget blackholes (supermassive)
33
densed, Earth-sized objects
White Dwarfs
34
stars with 0.5 solar mass
Low-mass stars
35
have masses 10 times that of the Sun, but are only about 20 miles across
Small black holes
36
\*stars with large radiating surfaces \*appear in the upper right position of H-R diagram
Red Giants
37
electrons are forced to combine with protons in the nucleus to produce neutrons
Neutron Stars
38
found in the center of galaxies are estimated to be millions of solar masses
it should become extremely hot and emit a flood of X-rays before it is engulfed
39
have 10 billion years
Yellow stars (sun-like)
40
useful tool for understanding Stellar Evolution
Hertzsprung-Russell Diagram
41
stars experience minimal change in size or energy output (balance maintained)
Main-sequence stage
42
gases that are pulled from the companion form an accretion disk while emitting a steady stream of X-rays
Black holes
43
gravitational attraction within a nebula causes..?
cloud to collapse on itself
44
Stellar Birth
interstellar clouds, rich in gas and dust \> gravitational contraction, pulling particles into the center \> as the cloud collapses, gravity is converted to thermal energy (increase in temperature)
45
extremely hot, their surface gravity is so immense that even light cannot escape
Black holes
46
smallest white dwarfs = ?
most massive
47
Stellar Evolution of Low Mass Stars
Nebula \> protostar \> main sequence (red) \> white dwarf
48
\>as a red giant, they fuse hydrogen and helium at accelerated rates and once fuel is exhausted, they collapse into a white dwarf \>without a source of nuclear energy, white dwarfs become cooler and dimmer
Medium-Mass Stars
49
\>independently studied the relationship between true brightness (absolute magnitude) and temperature of stars \>astronomers survey a portion of the sky and plot each star according to luminosity
Ejner Hertzsprung and Henry Russell
50
radiate energy more, depletion of fuel in just few billion years
Blue Stars
51
Every stage of a star’s life is ruled by..?
gravity
52
very immense stars
Super giants
53
have masses 1,000 times the Sun
intermediate black holes
54
with radius 800 times that of the sun
Betelgeuse
55
with rising temperature and pressure...
A star is born
56
radiate energy more, depletion of fuel in just few billion years
Red Stars
57
smallest white dwarfs were produced from...?
collapse of larger, more massive main-sequence stars