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Stellar and Galactic Astronomy Exam #1 > Astronomy Final Exam: Chapters 13, 14, & 15 > Flashcards

Astronomy Final Exam: Chapters 13, 14, & 15 Flashcards

1
Q

What are the two processes where fusion can take place?

A

Proton-proton chains & carbon-nitrogen-oxygen (CNO) cycle

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2
Q

A more massive star has what type of lifetime?

A

Shorter lifetime because nuclear fuel burns quicker

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3
Q

What is the Chandrasekhar Limit?

A

The maximum mass of a stable white dwarf

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4
Q

How many white dwarfs are out there?

A

8

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5
Q

What is the energy source of a white dwarf?

A

Thermal energy

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6
Q

What is a white dwarf?

A
  • dense low massive object with no nuclear fuel in core
    -Bigger than Earth but half as massive as the Sun
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7
Q

What is a planetary nebulae?

A

The region of cosmic gas & dust formed from the cast-off outer layers of a dying star

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8
Q

What is a supernova?

A

A colossal explosion of a star

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9
Q

What do supernova form?

A

Forms other stars due to shock wave of death collecting gas & dust

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10
Q

How often does a supernova happen?

A

3x a century

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11
Q

What are the types of supernovas?

A

Type II & Type Ia

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12
Q

How do Type II Supernova form?

A

Rapid collapse & violent explosion of a massive star

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13
Q

How do Type Ia Supernova form?

A

Binary system collision with one of the stars being a white dwarf

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14
Q

What is a nova?

A

An explosion from the surface of a white-dwarf star in a binary star system

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15
Q

When does a nova occur?

A

When a white dwarf “steals” gas from a companion star

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16
Q

What are event horizons?

A

The opening of a black hole where an observer would see time stopping & light is unable to escape

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17
Q

What is the Schwarzschild Radius?

A

The radius below which the gravitational attraction between the particles of a body must cause it to undergo irreversible gravitational collapse

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18
Q

How massive are black holes?

A

3-10 solar masses

19
Q

What is a black hole?

A

A region of spacetime where gravity is so strong that nothing, including light or electromagnetic waves, have enough energy to escape its event horizon

20
Q

What are neutron stars?

A

When a massive star runs out of fuel & collapses

21
Q

What are pulsars?

A

Highly magnetized rotating neutron stars that emit beams of electromagnetic radiation out of its magnetic poles

22
Q

What is the mass of neutron stars?

A

1.35 x the Sun’s mass usually

23
Q

What is neutron degeneracy pressure?

A

A pressure exerted by dense material consisting of fermions (like electrons in white dwarfs)

24
Q

What happens to neutron star pairs when they meet?

A

Merger leads to the formation of a more massive neutron star or a black hole

25
Q

Can the Sun ever become a black hole?

A

No, it would need to be 20x more massive

26
Q

What is an isolated black hole?

A

A black hole that traps light due to intense gravitational field & cannot be seen directly

27
Q

What are accretion disks?

A

A disk-like flow of gas, plasma, dust, or particles around any object in which what’s orbiting in the gravitational field of the object loses energy & angular momentum as it slowly spirals inward

28
Q

What are globular clusters?

A

Conglomeration of stars

29
Q

Where are globular clusters located?

A

Galaxy’s halo

30
Q

Why are globular clusters important?

A

Estimate the age of the Universe

31
Q

What does the Galaxy’s disk include?

A

Spiral arms

32
Q

What happens in the spiral arms?

A

Sites of ongoing star formation

33
Q

OB stars are good tracers because of why?

A

Their short lifetimes tell astronomers where recent stars were formed

34
Q

What is the Galaxy’s disk mostly made of?

A

gas & dust

35
Q

Where is the Supermassive Black Hole?

A

The Galactic Center of the Milky Way

36
Q

How was the Supermassive Black Hole discovered?

A

Radio telescopes discovered a dim speck

37
Q

How many solar masses is the Supermassive Black Hole?

A

4.154 +- 0.014 million solar masses

38
Q

What were the first stars?

A

Population II

39
Q

What were the first stars composed of?

A

Hydrogen & helium

40
Q

What is a cepheid variable star?

A

A variable star that pulses radically, varying in diameter & temperature

41
Q

What do cepheid variable stars measure?

A

Interstellar & intergalactic distances

42
Q

What is dark matter?

A

Nonluminous material that is postulated to exist in space (theorized to make approx. 85% of matter)

43
Q

What is the Milky Way Galaxy?

A

Galaxy that is includes our solar system

44
Q

How massive is the Milky Way Galaxy?

A

1.5 trillion solar masses

Stellar and Galactic Astronomy Exam #1 (9 decks)

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