Doppler-shift observations of a spectroscopic binary star can enable astronomers to calculate ...

Doppler-shift observations of a spectroscopic binary star can enable astronomers to calculate ________ of its individual stars.
 
  a. the minimum masses
  b. the sizes
  c. both minimum masses and sizes
  d. neither minimum masses nor sizes

Question 2

Compared to a smaller-objective lens, a larger-objective lens makes a star's image
 
  a. brighter.
  b. dimmer.
  c. no effect.

Question 3

A pair of stars orbit around one another in an elliptical orbit with a semi-major axis, a, of 1 AU with an orbital period, P, of 1 year. What is the mass of the pair of stars?
 
  a. 1 solar masses
  b. 2 solar masses
  c. 4 solar masses
  d. 8 solar masses
  e. 16 solar masses

Question 4

An ordinary glass lens forms an image by ____________ of light.
 
  a. reflection
  b. refraction
  c. diffraction