I know it's a simple question, but even I progressed in astronomy, I always had this question. So, I know the Sun, in the MK classification system, it's G2: yellow. But I also know the sun, in visible spectrum, is white! But when I search for NASA photos of Sun in this spectrum, I find some photos with the Sun being yellow, and others white, with some of them being even orange! What is happening here? Is something incorrect?
Although the emission peak of light in the solar spectrum is more or less in the yellow-green part of the visible spectrum, it also emits a lot of red and blue light, and about the same quantity. Suppose you combine all the colors (talking about light), then you basically see white.
If you see NASA images of the sun, they are false color images, you could make them look whatever color you like, but they do not represent what the eyes would really see.
In this emission spectrum, we can see, there is a considerable amount of all visible colors being emitted so the light will appear as white to us from space. But when observed from Earth due to Rayleigh scattering and the presence of these bluish colors being more than reddish ones the bluish colors are easily scattered giving the sky a blue color, now the light reaching us from the sun has more yellow-reddish colors, and that's why the sun seems yellow to us when observed from the ground. The colours of stars as per MK system is what the observer might observe without any optical aid, ie the light has been filtered in the atmosphere before reaching the observer. The yellow sun in outer space is generally an edited image of the Sun. This is the true color photo of the Sun.