Question

To calculate the dashed orbits from the stellar positions, astronomers had to assume that __________.

A. if they observed for many more years, the dots would trace out ellipses
B. the stars are all main-sequence stars
C. if they observed for many more years, the dots would trace out parabolas
D. the central object has a mass of about 4 million solar masses

Answer 1

A. if they observed for many more years, the dots would trace out ellipses.

Step-by-step explanation:

To calculate the dashed orbits from the stellar positions, astronomers had to assume that A. if they observed for many more years, the dots would trace out ellipses.

Generally the orbitals the stellar objects when traced over the year are elliptical.