Neutron Stars and Black Holes - Chapter 22
The mass range for neutron stars is:
1.4 to 3 solar masses.
Which of the following are attracted by gravity?
Antimatter, any object with mass, electromagnetic radiation, neutrino - All of the above
The observed slowing of a clock in the vicinity of a black hole is a prediction of:
General relativity.
What explanation does general relativity provide for gravity?
Gravity is the result of curved spacetime.
What would happen if more mass was added to a 1.4 solar mass neutron star?
It could eventually become a black hole, via a hypernova explosion.
Which of the following can actually escape from inside a black hole's event horizon?
None of the above
What compelling evidence links pulsars to neutron stars?
Only a small, very dense source could rotate that rapidly without flying apart.
A neutron star detectable by its rapid rotation and strong magnetic field is called a(n) ________.
Pulsar
What would happen if mass is added to a 1.4 solar mass white dwarf?
The star would erupt as a carbon detonation (type I) supernova.
What are X-ray bursters?
They are neutron stars on which accreted matter builds up, then explodes in a violent nuclear explosion.
A hypernova creates:
a black hole.
X-ray bursters occur in binary star systems. The two types of stars that must be present to make up such an object are:
a main sequence or giant star and a neutron star in a mass transfer binary.
Three terrestrial-sized planets in orbits of a fraction of an AU have been found near:
a millisecond pulsar.
Most pulsars have a measured mass of:
about 1.4 solar masses
The average density of neutron stars approaches:
about 1017 kg/m3, similar to the density of atomic nuclei.
A black hole may be visible because electromagnetic radiation is emitted from a(n) ________ surrounding it, heated up enough to emit X-rays.
accretion disk
If light from a distant star passes close to a massive body, the light beam will:
bend towards the star due to gravity.
Two important properties of young neutron stars are:
extremely rapid rotation and a strong magnetic field.
The densely packed neutrons of a neutron star cannot balance the inward pull of gravity if the total mass is:
greater than Schwartzschild's limit of 3 solar masses.
In the Lighthouse Model,
if the beam sweeps across us, we will detect a pulse of radiation.
Michelson and Morley demonstrated that the speed of light is ________ of the motion of the observer.
independent
The largest known black holes
lie in the cores of the most massive galaxies.
A method for identifying a black hole is to:
look for their effects on nearby companions.
In a neutron star, the core is:
made of compressed neutrons in contact with each other.
A normal neutron star is spun up to a millisecond pulsar by accretion of matter from a ________ binary companion.
mass transfer
As its name implies, in a(n) ________ star the protons and electrons are fused together and the charges eliminated via neutronization.
neutron
To which of these phenomena are X-ray busters most similar?
novae
A rapidly rotating compact star that emits a beam of energy like a cosmic lighthouse is usually found by observation at ________ wavelengths.
radio
The idea of rapidly rotating white dwarf stars to explain pulsars was immediately ruled out because such objects would not be ________ enough to spin that rapidly.
small
The rate of flashing of a pulsar is a measure of its ________.
spin or rotation
Pulsars:
spin very rapidly when they're young.
A gamma-ray burster emits a quantity of energy similar to that emitted in a _________.
supernova or supernova explosion.
If a neutron star attains a mass over ________ solar masses it becomes a black hole.
three
The Crab Nebula and its pulsar were produced by a ________ supernova.
type II or core-collapse
If the Sun were replaced by a one solar mass black hole:
we would still orbit it in a period of one year.
The key to identifying a black hole candidate in a binary system is that:
we would still orbit it in a period of one year.
