10.5

Stellar distances

Assesment statements

- Define the parsec

- Describe the stellar parallax method of determining the distance to a star

- Explain why the method of stellar parallax is limited to measuring stellar distances less than several hundred parsecs

- Solve problems involving stellar parallax

The parsec is defined as the angle subtended at the star.

If the distance to a star is 1 pc, the angle subtended, theta will be 1 second.

This makes calculations much easier since the distance in pc is simply 1/the angle in seconds

- Arc seconds

One degree can be split up into 60 arc minutes and each arc minute into 60 arc seconds, so there are 3600 arc seconds in one degree.

In radians 1 arc second is therefore (1/3600) x (2pi/360)

	Created by Moa Lindström over 10 years ago

short notes about 10.2 - stellar radiation and stellar types, and 10.5 - stellar distances