Spiral arms can be traced through the sun's neighborhood by locating the positions of spiral tracers such as:
A. Cepheid variable stars.
B. globular clusters.
C. type Ia and type II supernovae.
D. massive stars.
Answer:D
Spiral arms can be traced through the sun's neighborhood by locating the positions of spiral tracers such as:
A. Cepheid variable stars. B. globular clusters. C. type Ia and type II supernovae. D. massive stars.