Review of Distance to Stars

Astronomy 25

1) Three methods to determine stellar distances are ________ parallax,

________ parallax, and ________ stars.

2) The most accurate method, good out to about 160 ly, is _______________.

3) Using this method, we can measure the very small parallax angle using an

Earth base-distance of ________.

4) About ________ stars, measured both from Earth and the Hipparcos

satellite, have had their distances calculated this way.

5) These stars, our most valuable catalogue, have been plotted on the

____________ diagram, temperature vs. absolute magnitude or luminosity.

6) The stars on this diagram very often fall on a diagonal line called the

______ _______.

7) For more distant stars, we must first use a photometer to measure their

________ magnitude (m) and a spectrometer to measure its ________.

8) We then place this star in an appropriate place on the diagram and are

able then to read its __________ ________ (M) to the left.

9) Knowing both M and m we can calculate the star’s _________.

10) In 1912, Henrietta Leavitt paid particular attention to a group of stars

whose light _______ over regular periods of time.

11) Comparing the periods of distant stars to similar stars whose distance was

determined by another method, she concluded that their _________

magnitudes were probably the same, solving the distance puzzle.