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Explorations an Introduction to Astronomy Thomas T. Arny | ||||||||
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Chapter
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Chapter 16, Figure 15
Figure
16.15
Finding the
distance to a galaxy using Cepheid variables as standard candles. B*
and Bg are the apparent brightness of the Cepheid in the Milky
Way and in the Cepheid distant galaxy, respectively. Their distances are d*
and dg, respectively. From a measurement of the brightness ratio
of the Cepheids, astronomers can calculate the ratio of their distances and,
knowing the distance of the Cepheid in the Milky Way, they can therefore find
the distance to the other galaxy.
