Question

6. Which of the following are steps toward measuring the distance to stars using spectroscopic parallax? a) Measure the star’s spectral type and calculate the mass. b) Measure the star’s spectal type and the apparent brightness, i.e., the flux. c) Measure the star’s rotation period and the number of starspots. d) Measure the star’s orbital period if it is in a binary and use that to estimate the spectral types of both stars. e) Measure the slight wobble in the star’s motion caused by planets orbiting the star.

What single piece of information revolutionized our understanding of “spiral nebulae”, such as the spiral nebula in Andromeda, to show that they are spiral galaxies full of stars? a) We measured their average temperature. b) We placed them on the Hertzsprung-Russel diagram. c) We measured their distance. d) We measured their parallax. e) We measured their orbital periods

2. Which statement about our Galaxy, the Milky Way, is true? a) The halo contains no O and B stars while the disk contains stars of all spectral types. b) The halo contains only young stars while the disk contains stars of all ages. c) The halo contains hundreds or perhaps thousands of “super-massive” black holes. d) Our Sun is located a few light years from the center of our Galaxy. e) The Milky Way is unique in having no smaller galaxies orbiting around it.

Answer 1