parsecs or light years
Light years
That is one of the things scientists use to help them measure a stars distance but it isn't just based on the color.
preallax
Usually such distances are measured either in light-years, or in parsecs.
Stellar parallax
Parallax
For nearby stars, the parallax method gives the most accurate measure of distances.For nearby stars, the parallax method gives the most accurate measure of distances.For nearby stars, the parallax method gives the most accurate measure of distances.For nearby stars, the parallax method gives the most accurate measure of distances.
by the property of reflection or electromagnetic waves
Stellar distances, like the distances of stars and galaxies from Earth
another unit for measuring distances is AU (Astronmical Unit)
because the stars are very far away so the astronomers use light years
Parallax is the apparent change in position of an object when you look at it from different angles. Astronomers often us parallax to measure distances to nearby stars. This method can be used to determine stars' distances up to 400 light-years from Earth.