LECTURE 19, NOVEMBER 4, 2010

ASTR 101-3, FALL 2010 1

LECTURE 19, NOVEMBER 4, 2010

ASTR 101, SECTION 3INSTRUCTOR, JACK BRANDT

[email protected]

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a) its mass exceeds the Chandrasekhar limit.b) its electron degeneracy increases enormously.c) fusion reactions increase in it’s core.d) iron in its core collapses.e) the planetary nebula stage ends.

Question 13

A white dwarf can explode when

a) its mass exceeds the Chandrasekhar limit.b) its electron degeneracy increases enormously.c) fusion reactions increase in it’s core.d) iron in its core collapses.e) the planetary nebula stage ends.

Question 13

A white dwarf can explode when

If additional mass from a companion star pushes a white dwarf beyond 1.4 solar masses, it can explode in a Type I supernova.

Question 14

A Type II supernova occurs when

a) hydrogen fusion shuts off.b) uranium decays into lead.c) iron in the core starts to fuse.d) helium is exhausted in the outer layers.e) a white dwarf gains mass.

a) hydrogen fusion shuts off.b) uranium decays into lead.c) iron in the core starts to fuse.d) helium is exhausted in the outer layers.e) a white dwarf gains mass.

Question 14

A Type II supernova occurs when

Fusion of iron does not produce energy or provide pressure; the star’s core collapses immediately, triggering a supernova explosion.

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a) in the Big Bang.b) by nucleosynthesis in massive stars.c) in the cores of stars like the Sun.d) within planetary nebulae.e) They have always existed.

Question 2

Elements heavier than hydrogen and Helium were created

Question 2

Elements heavier than hydrogen and helium were created

Massive stars create enormous core temperatures as red

supergiants, fusing helium into carbon, oxygen, and even

heavier elements.

a) in the Big Bang.b) by nucleosynthesis in massive stars. c) in the cores of stars like the Sun.d) within planetary nebula e) They have always existed.

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a) pulsars can be used as interstellar navigation beacons.

b) the period of pulsation increases as a neutron star collapses.

c) pulsars have their rotation axis pointing toward Earth.

d) a rotating neutron star generates an observable beam of light.

Question 3

The lighthouse model explains how

Question 3

The lighthouse model explains how

a) pulsars can be used as interstellar navigation beacons.

b) the period of pulsation increases as a neutron star collapses.

c) pulsars have their rotation axis pointing toward Earth.

d) a rotating neutron star generates an observable beam of light.

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ASTR 101-2, SPRING 2006

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a) matter spiraling into a large black hole.b) the collision of neutron stars in a binary

system.c) variations in the magnetic fields of a

pulsar.d) repeated nova explosions.e) All of the above are possible.

Question 4

One possible explanation for a gamma-ray burster is

a) matter spiraling into a large black hole.b) the collision of neutron stars in a binary

system.c) variations in the magnetic fields of a

pulsar.d) repeated nova explosions.e) All of the above are possible.

Question 4

One possible explanation for a gamma-ray burster is

Gamma-ray bursts vary in length, and the coalescence of two neutron

stars seems to account for short bursts.