Why would a star show little parallax?
We can tell the distance of stars using their parallax (or apparent change in position) as the Earth moves in its orbit. Stars that are very close have the highest parallax and stars that are far away have very little. Alpha Centauri, the sun-like star nearest to our solar system, has a distance of 4.3 years and a parallax of 0.75″, which is the highest of any object outside our solar system. The farthest away stars that we can parallax using the Earth’s movements are about 1,600 light years away. So a star with little parallax must be approaching this limit on the distance. Just to give you some intuition on how parallax works, do this simple experiment. We can tell the distance of objects here on Earth from us using the parallax between our two eyes (your brain does this for you automatically, so you don’t even notice, but this is how you have depth perception.) Hold your finger about 6 inches from your face and look at it with only your left eye open. Now look at it with only your r
