Suppose you are an astronomer on Jupiter (distance to the Sun = 5 AU).You observe a star with a parallax of 0.1 arcseconds.What is the star's distance?
A)0.1 pc
B)2 pc
C)5 pc
D)50 pc

Question

Quizplus · Accepted Answer

Parallax is inversely proportional to the distance of the observed object. Since the parallax angle is 0.1 arcseconds, we can use the formula 1/p = d/1 AU to find the distance (d) in parsecs.

1/p = 1/d 
0.1 arcseconds = 1/d 
d = 1/0.1 pc 
d = 10 pc

However, we need to take into account that we are observing from Jupiter, which is 5 AU away from the Sun. So, the distance of the star would be 5 more than the distance we calculated.

d = 10 pc + 5 AU 
d = 10 pc + (5 x 149.6 million km) 
d = 10 pc + 748 million km 
d = 50 pc

Therefore, the star's distance is 50 pc. The correct answer is D).

Suppose You Are an Astronomer on Jupiter (Distance to the Sun