Pathways to Astronomy

Stephen E. Schneider

Chapter 57 The Sizes of Stars - all with Video Answers

Educators

Chapter Questions

Problem 1

Alpha Centauri is actually two stars that orbit each other Recent measurements show that Alpha Centauri A has an angular diameter of 0.0085 arcsec, while Alpha Centauri B has an angular diameter of 0.0060 arcsec. The pair are at a distance of 4.4 ly. What are their diameters, compared to the Sun's?

Farhanul Hasan

Numerade Educator

05:18

Problem 2

A star with the same color as the Sun is found to produce a luminosity 81 times larger. What is its radius, compared to the Sun's?

Matthew Miranda

Numerade Educator

02:32

Problem 3

A star with the same radius as the Sun is found to produce a luminosity 81 times larger. What is its surface temperature, compared to the Sun's?

Hubert Agamasu

Numerade Educator

02:41

Problem 4

The surface temperature of Arcturus is about half as hot as the Sun's, but Arcturus is about 100 times more luminous than the Sun. What is its radius, compared to the Sun's?

Prabhu Ramji

Numerade Educator

02:09

Problem 5

If a star's surface temperature is $30,000 \mathrm{K},$ how much power does a square meter of its surface radiate?

Vishal Gupta

Numerade Educator

02:18

Problem 6

Betelgeuse is roughly the same temperature as Proxima Centauri, the closest star to the Earth aside from the Sun. However, it is $10^{9}$ times brighter. How much larger in radius is Betelgeuse than Proxima Centauri?

Ajay Singhal

Numerade Educator

00:56

Problem 7

A star is five times as luminous as the Sun and has a surface temperature of $9000 \mathrm{K}$. What is its radius, compared to that of the Sun?

Farhanul Hasan

Numerade Educator

02:18

Problem 8

Using the information that Betelgeuse has an angular size 0.05 arcsec and is 130 pc from the Earth, show how you can calculate its diameter in kilometers.

Ajay Singhal

Numerade Educator