Final answer:
Stars moving away from us appear redshifted due to the stretching of light wavelengths as they move, which makes them appear redder than their actual emitted light. The color of a star is also indicative of its temperature, with hotter stars tending to be bluish and cooler stars reddish, even without considering their motion relative to the observer.
Step-by-step explanation:
When stars move away from a telescope, they appear to be redshifted, meaning their light is shifted to longer, redder wavelengths compared to the light they emit. This phenomenon is a consequence of the Doppler effect, which states that light from objects moving away from an observer tends towards longer wavelengths. As the star moves farther away, the light waves stretch out, leading to an increase in wavelength, and hence shifting towards the red part of the spectrum. This redshift is an important tool for astronomers to measure the movement of stars and galaxies in the universe.
Conversely, if a galaxy or star were moving toward us, its light would be blueshifted, or shifted to shorter, bluer wavelengths. Dust in the interstellar space interacts differently with various colors of light as well, sometimes causing additional reddening which is more accurately described as 'deblueing' since it involves the subtraction of blue tones rather than the addition of red tones.
The overall color of stars is directly related to their surface temperatures, as described by Wien's law. Hot stars emit more light at blue wavelengths, while cooler stars emit more at red wavelengths, independent of their movement or position in space.