Cepheid variable stars are used to determine the distances to globular clusters in the Milky Way halo because these stars:
A. are companion stars of neutron stars or black holes.
B. have periods are correlated with their luminosities.
C. contain trace amounts of dark matter.
D. are brighter than O- and B-type main sequence stars.
Answer:B
Cepheid variable stars are used to determine the distances to globular clusters in the Milky Way halo because these stars:
A. are companion stars of neutron stars or black holes. B. have periods are correlated with their luminosities. C. contain trace amounts of dark matter. D. are brighter than O- and B-type main sequence stars.