eli5: when a star leaves the observable universe due to expansion, does it get fainter over time from our perspective, or it just appears to turn off, like a flashlight?

Question

eli5: when a star leaves the observable universe due to expansion, does it get fainter over time from our perspective, or it just appears to turn off, like a flashlight?

In: 30

Answer 1

They emit photons of various wavelengths, thus they will appear to dim as a larger percentage of the light redshifts out of the visible spectrum.