PHYS104 FINAL

Approximately how long does it take the photons released in nuclear reactions in the core of the Sun to exit the Sun?

100,000 years

We observe neutral hydrogen gas using

21-cm emission

Star A and star B appear equally bright, but star A is twice as far away from us as star B. Which of the following is true? A. Star A is twice as luminous as star B B. Star A is four times as luminous as star B

B. Star A is four times as luminous as star B

Which of the following are created by solar magnetic activity? A. sunspots B. prominences C. solar flares D. all of the above

D. all of the above

stars with a larger brightness must be: A. closer to us than fainter stars B. larger in size than fainter stars C. more luminous than fainter stars D. any combination of the above

D. any combination of the above

How do we understand the very fast rotation of neutron stars?

It is a consequence of the conservation of angular momentum applied to collapsing objects

What mechanism provides the internal pressure inside a neutron star?

degenerate pressure from neutrons

When looking at the space between stars, what might you see?

gas

A protostar is in ___________ as it collapses

hydrostatic equilibrium

When a spectral type G2 star like the Sun leaves the main sequence, its luminosity ______ and its surface temperature ________

increases; decreases

A low-mass star that burns helium in its core and hydrogen in a shell surrounding the core is ________ luminous than a similar star that burns hydrogen only in its core

more

The _______ massive a main-sequence star is, the more hydrogen it has to burn, and the ________ it's main-sequence lifetime lasts

more; shorter

When a molecular cloud fragments, the ______ massive stars are the first to form, while the ______ massive stars take longer

most; least

What critical event transforms a protostar into a normal main-sequence star?

nuclear fusion begins in the core

The collapse of the core of a high-mass star at the end of its life lasts approximately

one second

The solar neutrino problem was solved by

postulating that neutrinos had mass and oscillated between three different types

When radiation from an object passes through the interstellar medium, the object appears

redder and dimmer

Massive stars explode when they

run out of nuclear fuel in their cores, and the cores collapse

Asymptotic giant branch stars have high-mass loss rates because they have low ___________

surface gravity

The detection of solar neutrinos confirms that

the Sun's core is powered by proton-proton fusion

What ionizes the gas in a planetary nebula and makes it visible?

ultraviolet photons emitted by a white dwarf