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Pathways to Astronomy

Stephen E. Schneider

Chapter 49

The Sun, Our Star - all with Video Answers

Educators

Chapter Questions

03:45

Problem 1

The Sun's angular size is $0.5^{\circ},$ and its distance is $1.5 \times 10^{8} \mathrm{km}$ Use this information to calculate the Sun's diameter.

Willis James
Willis James
Numerade Educator
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Problem 2

Calculate the Sun's average density in kilograms per liter. The Sun's mass is approximately $2 \times 10^{30} \mathrm{kg} .$ Its radius is approximately $7 \times 10^{8} \mathrm{m} .$ Show that its average density is approximately $1.4 \mathrm{kg} / \mathrm{L}$.

Ankur S
Ankur S
Numerade Educator
01:23

Problem 3

How much mass would the Sun have to lose each second in order to lose $10 \%$ of its mass in 10 billion years?

Rehmat Kazmi
Rehmat Kazmi
Numerade Educator
07:53

Problem 4

At the rate at which the Sun is losing mass in the solar wind, how many years does it take the Sun to lose as much mass as the mass of the entire Earth?

Linda Winkler
Linda Winkler
Numerade Educator
01:33

Problem 5

Wolf-Rayet stars have very strong stellar winds, losing as much as $10^{-5} M_{\odot}$ per year. If a typical Wolf-Rayet star is $20 \mathrm{M}_{\odot}$, what percentage of its mass might it lose in a million years?

Zachary Warner
Zachary Warner
Numerade Educator
00:43

Problem 6

Suppose you were an astronomy student on Jupiter. Use the orbital data for Jupiter (distance from Sun 5.2 AU; period 11.8 years) to measure the Sun's mass using the modified form of Kepler's third law.

James Kiss
James Kiss
Numerade Educator
04:18

Problem 7

If a packet of gas rising through the interior of the Sun reduces its temperature from 1.5 million $\mathrm{K}$ to $10,000 \mathrm{K}$ and has a density decrease from $120 \mathrm{kg} / \mathrm{L}$ to $5.5 \mathrm{kg} / \mathrm{L}$, by what factor has the pressure on it changed?

Guilherme Barros
Guilherme Barros
Numerade Educator