ASTR 1102 Final Exam Summer B Rob Parks
Order the following objects from smallest to largest, according to their radii. 1Msun Star 1.5Msun Neutron Star 1Msun Black Hole 1Msun White Dwarf
1Msun Black Hole, 1.5Msun Neutron Star, 1Msun White Dwarf, 1Msun Star
Which galaxy type is shaped like a rugby ball?
E5
On the basis of how the life cycles of stars affect the composition of interstellar gas with time, rank the expected metallicities of the following components of our galaxy in order from lowest to highest.
Halo, Bulge, Thin Disk
How does the energy production in a high-mass, main-sequence star differ from energy production in the Sun?
High-mass stars use carbon in a process that fuses hydrogen to helium, and high mass stars produce energy at a faster rate
What causes a high-mass star to explode as a Type II supernova?
Iron absorbs energy when it fuses.
What would happen to a protostar that formed without any rotation at all?
It would not have planets
How does mass determine the main-sequence lifetime of a star?
More massive stars burn fuel faster than low-mass stars and thus have shorter lives
Which of the following pieces of evidence support(s) the theory that the Milky Way is a spiral galaxy?
Ongoing star formation occurs in clouds of gas and dust. The 21-cm radiation emitted from neutral hydrogen clouds shows the existence of spiral arms. Most stars in our galactic neighborhood share the same relative motion around the galactic center.
Why does on-going star formation lead to a blue-white appearance?
Short-lived blue stars outshine the others.
If gas and dust are dark to visible telescopes, how do we know they exist in space?
Sometimes absorption lines are seen from interstellar gas between the Earth and a galaxy. Infrared telescopes can see cool dust. Radio telescopes can detect interstellar gas.
Which parts of the Milky Way contain old stars, and which contain young stars?
The disk contains young and old stars; the halo contains mostly old stars.
If a star follows a horizontal path across the H-R diagram, the star
The star is getting redder The star is getting larger
Which property is detectable for both dark matter and the supermassive black hole at the center of the Milky Way?
Their gravity
Describe the path of the golf balls when they come just inside the edge of the dip created by a bowling ball placed in the center of the rubber sheet.
They would follow a curved path.
Why is the Andromeda Galaxy now moving toward us?
This is due to the mutual gravitational attraction between the Milky Way and Andromeda galaxies.
Astronauts in the International Space Station
are in free fall
The Large Magellanic Cloud and Small Magellanic Cloud will probably
become part of the Milky Way.
Astronomers detect dark matter
by comparing luminous mass to gravitational mass.
Hubble's law was discovered using measurements of two properties of a galaxy: <blank1> and <blank2>.
distance; recession velocity
A white dwarf will become a supernova if
enough mass accretes from a companion to give the white dwarf a total mass of 1.38 MSun.
When the Sun runs out of fuel in its core, the core will be
filled with helium.
Stars begin burning helium to carbon when the temperature rises in the core. This temperature increase is caused by
gravitational collapse.
If a neutron star is more than three times as massive as the Sun, it collapses because
gravity overpowers the force of neutron degeneracy.
Where are the youngest stars in the Milky Way Galaxy?
in the disk
Einstein's formulation of gravity:
is approximately equal to Newton's universal law of gravitation for small gravitation fields. explained why Newton's universal law of gravitation describes the motions of masses.
A planetary nebula glows because
light from the central star causes emission lines
Supermassive black holes
occur in most, perhaps all, large galaxies.
One reason astronomers think neutron stars were formed in supernova explosions is that
pulsars sometimes have material around them that looks like the ejecta from supernova
According to Einstein's general theory of relativity, gravity is the
result of the distortion in spacetime around a massive object.
All the light in an AGN outburst travels
same speed
Galaxies are classified according to
shape
Currently, stars form in
spiral galaxies
A globular cluster with no variable stars would have been left out of Shapley's study because
the distance to the cluster could not be determined.
A planetary nebula forms from
the ejection of mass from a low-mass star.
The energy required to begin nuclear fusion in a protostar originally came from:
the gravitational potential energy of the protostar.
A neutron star is
the remains of a star that died in a massive star supernova (if no black hole was created)
If a black hole suddenly doubled in mass, the event horizon would become <blank> its original size.
twice
If the main-sequence turnoff of s star's cluster occurs near the very top of the main sequence, then the star cluster is
very young