AST 111

Which layer of the Sun is the coolest?The photosphere is the coolest.
Which of these groups of particles has the greatest mass?Four individual protons have the most mass.
Scientists estimate the central temperature of the Sun using……mathematical models of the Sun.
At the center of the Sun, fusion converts hydrogen into……helium, energy, and neutrinos.
Solar energy leaves the core of the Sun in the form of……photons.
How does the number of neutrinos passing through your body at night compare with the number passing through your body during the day?They are about the same.
Why do sunspots appear darker than their surroundings?They are cooler than their surroundings.
Which of these things poses the greatest hazard to communications satellite?Particles from the Sun pose the greatest hazard.
What causes the cycle of solar activity?Changes in the organization of the Sun’s magnetic field.
If the star Alpha Centauri were moved to a distance 10 times farther than it is now, its parallax angle would……get smaller.
What do we need to measure in order to determine a star’s luminosity?Apparent brightness and distance is used.
What two pieces of information would you need in order to measure the masses of stars in an eclipsing binary system?The time between eclipses and the average distance between the stars is needed.
Which of these stars has the coolest surface temperature?A K star has the coolest surface temperature.
Which of these stars is the most massive?A main sequence A star is the most massive.
Which of these stars has the longest lifetime?A main sequence M star has the longest lifetime.
Which of these stars has the largest radius?A supergiant M star has the largest radius.
Which of these stars has the greatest surface temperature?A 30 Msun main sequence star has the greatest surface temperature.
Which of these star clusters is oldest?A cluster whose brightest main sequence stars are yellow is the oldest.
Stars can form most easily in clouds that are……cold and dense.
A brown dwarf is……an object not quite massive enough to be a star.
What happens to a low mass star after a helium flash?Its luminosity goes down.
What would you be most likely to find if you returned to the solar system in 10 billion years?The Sun would be a white dwarf.
Which of these stars does not have fusion occurring in its core?A red giant does not have fusion.
What would stars be like if hydrogen had the smallest mass per nuclear particle?Nuclear fusion would not occur in stars of any mass.
What happens to the core of a high mass star after it runs out of hydrogen?It shrinks and heats up.
Which of these isolated neutron stars must have had a binary companion?An isolated pulsar that pulses 600 times per second.
What would happen to a neutron star with an accretion disk orbiting in a direction opposite to the neutron star’s spin?It’s spin would slow down.
What would happen if the Sun suddenly became a black hole without changing its mass?Earth’s orbit would not change.
Which of these binary systems is most likely to contain a black hole?An X-ray binary containing an O star and another object of equal mass.
How would a flashing red light appear as it fell into a black hole?Its flashes would shift to the infrared part of the spectrum.
Which of these black holes exerts the weakest tidal forces on an object near its event horizon?A 106 Msun black hole exerts the weakest tidal force.
Where do gamma-ray bursts tend to come from?Extremely distant galaxies produce gamma-ray bursts.