The sun is actually white, not yellow — its visible wavelengths reach Earth as white light, but our atmosphere scatters the shorter blue wavelengths more efficiently, making the solar disk appear golden

The UCAR Center for Science Education puts it plainly: sunlight reaches Earth’s atmosphere as white light. Those molecules are much smaller than a wavelength of visible light, and when light meets something that small it scatters sideways in every direction rather than bouncing off cleanly. Blue light is short. A great many familiar solar images are captured in narrow slices of the spectrum, often outside visible light altogether, then colour-coded afterwards so the features can be told apart. This is why paper looks white under a kitchen bulb and white again outdoors, despite the two light sources being nothing alike.