Exploring the Cosmos - Degree Exam 2014 - Life and Death of Stars (Part 2)
1. Electron degeneracy
prevents neutron star formation in solar-like stars.
causes pulsars to have a strong magnetic ï¬eld.
prevents black hole formation in massive stars.
prevents the Sun from collapsing within a few years.
2. Globular clusters
are recently formed collections of approximately 10^6 stars.
contain mainly stars of low metallicity.
are probably the largest clusters of stars in the Universe.
are found in elliptical but not spiral galaxies.
3. Black holes
are often observed due to their tidal effect on nearby matter.
can never be observed.
are often observed by their tidal effect on the Earth.
have never been observed.
4. Neutrinos
are mainly associated with type Ia supernovae.
carry most of the energy away from a type-II supernova.
are too weak to have any effect.
cause massive stars to collapse.
5. A main-sequence star 10 times as massive as the Sun
is much denser than the Sun so has roughly the same diameter.
obtains most of its energy by the triple alpha process.
has a core temperature that is much higher than that of the Sun.
has about 10 times the amount of hydrogen and so burns approximately 10 times longer than the Sun.
6. Analysis of the H-R diagram for a cluster is a good means to
count the number of stars in the cluster.
estimate the distance to the cluster.
estimate the age of the cluster.
estimate the mass of dust in the cluster.
7. Neutron stars
can rotate at a rate of more than 100 revolutions per second.
are about the same density as white dwarfs, but made of nuclear material.
are very dense and so cannot rotate faster than about once an hour.
contain most of the neutrinos in the known Universe.
8. Open clusters are
an unnamed constellation.
any number of stars in a group.
several stars weakly bound by gravity.
several galaxies weakly bound by gravity.
9. T Tauri stars, EGGs and Bok globules are associated with
star death.
most pulsars.
star birth.
main sequence stars.
10. Pulsars
are made of neutrons and so have zero electric and magnetic ï¬eld.
have not yet been detected.
are known to be nearly perfect spheres.
pulse uniformly over their whole surface in a perfectly synchronised manner.
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