Question

Determining the distance to stars can be challenging. The parallax method is one way of finding the distance to many stars around us. Your research team measures the parallax of two stars that have a distance of 5 degrees from each other in the night sky: The first star has a parallax of 0.11 arcsec, and the second has a parallax of 0.13 arcsec. How far apart are the two stars from each other? Express your answer in light-years​

Answer 1

The parallax method relies on measuring the apparent shift in position of a star against the background of more distant stars as the Earth orbits the Sun. The angle of this shift is called the parallax angle, and it can be used to calculate the distance to the star.

To determine the distance between the two stars in the problem, we need to use some trigonometry. Since the stars are 5 degrees apart in the night sky, we can use the formula:

distance = (angular separation / 2) x (1 / parallax)

Plugging in the values for the first star, we get:

distance1 = (5 / 2) x (1 / 0.11) = 22.7 light-years

And for the second star:

distance2 = (5 / 2) x (1 / 0.13) = 19.2 light-years

Now, we can use the Pythagorean theorem to find the distance between the two stars:

distance between stars = √(distance1^2 + distance2^2) = √(22.7^2 + 19.2^2) = 29.4 light-years

Therefore, the two stars are about 29.4 light-years apart from each other.