Most nearby stars move relative to the Sun at speeds below about 30 km/s. Suppose you observe a nearby star that is moving much faster than this (say, 300 km/s). Which of the following is a likely explanation for its high speed?
A)It is a very high mass star.
B)It is a very young star, recently formed.
C)It is probably a halo star that is currently passing through the disk.
D)It has been pushed to high speed by the shock wave from a nearby supernova.

Question

Quizplus · Accepted Answer

Halo stars, which orbit in the halo of the Milky Way, often have high velocities compared to stars in the disk, including the Sun. When they pass through the disk, their relative speeds can be much higher than those of most nearby stars, making option C a likely explanation for the observed high speed.

Most Nearby Stars Move Relative to the Sun at Speeds