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