File:Altair (35529679801).png

English: Altair is a nearby main sequence rapidly rotating star which is spinning so fast that it is flattened along its poles. Another interesting thing about rapid rotators is the gradual darkening around the equator. These characteristics were predicted before the technology to observe them was created, but now both flattening and darkening have been observed using astronomical interferometers here on Earth. I do not know enough about stars or interferometers to write much more, so I will stop before I make some embarrassingly wrong mistake, assuming I haven't already...

This illustration is based on data collected by the CHARA array in 2006 for Monnier et al. More information on that can be found here: www-personal.umich.edu/~monnier/Altair2007/altair2007.html

I find that there is little interest in stars among the public at least compared to the excitement that surrounds planetary science. It is very frustrating to me personally that we have a singular example of a star to work with visually and everything else is a point source or, if we are lucky, a fuzzy blob as is the case with Betelgeuse which was recently resolved by ALMA. Even though I call it a fuzzy blob, it's still an astonishingly good picture which reveals some bright spots in the star's atmosphere.

Aside from the polar flattening and equatorial gravity darkening, I have read that these types of stars have polar outflows of gas coming out either end of them. I'm not sure what that might look like. Does it come out of just the center, or is it more diffuse? I also wonder if differential rotation might be represented by surface features in some stars. Our Sun and Jupiter both have differential rotation, but Jupiter has obvious banding while the Sun does not. Maybe it's too subtle to notice in the Sun. Might it be more obvious in other stars? Could convection play a role in the external appearance of such a star? Who can say? It's fun to speculate.

Anyway, illustrators don't have a lot to work with when dealing with stars. It's pretty much all the Sun with various tweaks applied. I can't say mine is much different. Nobody knows for sure what the surface of another star looks like beyond the most vague of details. I hope that one day we will see them better. I have a feeling they'll surprise us as much as the planets do.