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Conceptual Questions
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1

What is the distinction between a "wide pair" and a "close pair"?
2

Why are there few visual binaries with orbital periods of a few years or less?
3

How is it possible to tell that the orbit of a visual binary is tipped so that the apparent orbit isn't the true orbit?
4

Why are there few spectroscopic binaries in which the stars are separated by more than 10 AU?
5

Under what circumstances is the brightness of an eclipsing binary during primary minimum equal to the brightness during secondary minimum?
6

In an eclipsing binary system, star A is brighter, larger, and cooler than its companion, star B. What can be said about the depths of the minima when each of the stars is eclipsed?
7

What information in the light curve of an eclipsing binary tells about the relative sizes of the two stars?
8

The stars in a binary system are a 4 solar mass main sequence star and a 1 solar mass red giant. Explain why this binary system makes sense if the two stars are close together but is inconsistent with what we know about stellar evolution if the stars are a wide pair.
9

The surface of a lake is an equipotential while the surface of a river is not. What is the significance of this difference?
10

What is the significance of the Roche lobe of a star in a binary system?
11

Suppose a blob of gas is motionless at L1 in a binary system. Can the blob remain at L1? If not, is it possible to predict which way it will move?
12

Suppose the less massive star (star 2) in Figure 21.14 expands until it fills its Roche lobe. Describe what will happen as the star continues to expand.
13

Suppose the two stars in a binary system have masses of 1.5 and 2.5 solar mass. What will happen to the separation of the two stars if the 1.5 solar mass star sheds mass onto the 2.5 solar mass star?
14

What would happen to the distance between Jupiter and the Sun if the Sun shed mass onto Jupiter?
15

Explain why mass exchange can proceed very rapidly if the mass-losing star is the more massive of the pair.
16

Why do the stellar cores within a common envelope move closer together?
17

What are the two possibilities for the final state of a close, massive binary system?
18

What is the ultimate source of the energy emitted by accretion disks in binary systems?
19

What causes the gas in an accretion disk to spiral inward rather than to orbit at a constant distance from the compact object?
20

In a nova, why is the shell of hydrogen on the white dwarf consumed explosively rather than steadily?
21

Why is it possible for repeated nova explosions to occur in the same binary system?
22

What does mass exchange have to do with the occurrence of a type Ia supernova?
23

What happens on the surface of a neutron star to produce bursts of X rays?
24

Describe the evidence that Cygnus X-1 and A0620- 00 are binary systems containing black holes.







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