Pathways to Astronomy

Stephen E. Schneider

Chapter 60 Star Formation - all with Video Answers

Educators

Chapter Questions

Problem 1

Use Wien's law to find the wavelength of maximum radiation from a 2000 -K protostar. To what part of the electromagnetic spectrum does this wavelength belong?

Sheh Lit Chang

University of Washington

03:09

Consider a 2000 -K protostar that is the same diameter as the Sun. What is its luminosity, compared to the Sun? How many times bigger than the Sun would it have to be to emit 10 times more luminosity than the Sun?

Zachary Warner

Numerade Educator

00:39

Problem 3

The jets from a T Tauri star are measured to have speeds of about $300 \mathrm{km} /$ sec. At this speed, how long would it take the ejected material to travel 1 ly away from the protostar?

Chris Johnson

Numerade Educator

03:32

Problem 4

Suppose a molecular cloud begins with a mass of $1 M_{\odot}$ and has a radius of 1 ly. Imagine a dust grain at the outer edge of the cloud pulled straight inward, accelerating the entire way. When it reaches a radius of 1 million $\mathrm{km}$ from the center of the forming star, how fast will it be moving? (Hint: This problem is much easier to answer through the conservation of energy.)

Donald Albin

Numerade Educator

04:54

Problem 5

Compare the average density of a newly formed star of mass $20 M_{\odot}\left(\text { radius } \approx 10 R_{\odot}\right)$ and $0.1 M_{\odot}$ (radius $\approx 0.1 R_{\odot}$ ) to the Sun's density. You should find that the higher-mass star has a lower density. Relate these relative densities to the formation processes that determine the upper and lower mass limits for stars.

Willis James

Numerade Educator

01:49

Problem 6

Assuming that a $0.08-M_{\odot}$ brown dwarf has the same density as Jupiter (see Appendix Table 5 for data), what is its radius? Compare this radius to the Sun's radius.

Farhanul Hasan

Numerade Educator

Problem 1

Problem 2

Problem 3

Problem 4

Problem 5

Problem 6