Star Number on Fig. 4 |
Radial Velocity (km/sec) |
Angle q | Transverse Velocity (km/sec) | Proper Motion (arcsec/year) |
Distance (parsecs) |
---|---|---|---|---|---|

1 | 31.6 | 0.151 | |||

2 | 31.0 | 0.121 | |||

3 | 36.6 | 0.124 | |||

4 | 38.3 | 0.114 | |||

5 | 43.8 | 0.120 | |||

6 | 38.2 | 0.098 | |||

7 | 39.3 | 0.100 | |||

8 | 38.6 | 0.108 | |||

9 | 43.6 | 0.079 | |||

10 | 38.8 | 0.065 | |||

Average Distance: |
|||||

Error in Distance: |

- Give two reasons why distances to individual stars vary from each other.
- Could the distance to the Hyades be determined by annual parallax? Discuss.
- Using criteria of your choice, what is the diameter of the Hyades in parsecs?
- What is the mean distance in light years to the Hyades? What is the diameter of the Hyades in light years?
- The Hipparcos satellite was able to measure the parallaxes of 200 Hyades stars very reliably. The distance to the Hyades's center of mass has been pinpointed at 46.34 +/- 0.27 parsecs, or 151 +/- 0.9 light years.
- Compare your (albeit crude) results to the Hipparcos results.
- Why is it significant that Hipparcos has parallaxes for so many stars?
- What implication does this more accurate (and precise) measurement of the distance to the Hyades have for the size of the Universe?

- Compare your (albeit crude) results to the Hipparcos results.