Star A has a parallax angle that is 2 times bigger as star B. They both appear to be the same brightness, how does the luminosity of star A compare to the luminosity of star B?
The luminosity of a star is directly related to its brightness. If star A and star B appear to be the same brightness, it means they have the same luminosity.
Therefore, the luminosity of star A is the same as the luminosity of star B.