Comment by MarkusQ
10 hours ago
Right, that's what I'm objecting to. With tidal forces that strong, there should be no rotation parallel to the axis of tidal stretching. In the two-body reference frame the axis of rotation should be identical to the axis of rotation (tidal locking). So it should keep one pole towards the star.
The terminator is only secondarily significant here, but since it lies in a plane perpendicular to this axis, any bands should be parallel to it. But since this means that there will be a "hot side" and a "cold side" and convective cells between these will probably eliminate any banding.
Well, if it's tidally locked (which it probably is and the paper doesn't disabuse me), then both its rotation and orbit are about 8 hours on the sameish axis. So it's still spinning pretty dang fast, enough that the gas doesn't have to settle into hot and cold sides. I can't fully parse the part of the paper where they talk about the wind structure, but they do seem to think it still has some banding. Section 5: https://iopscience.iop.org/article/10.3847/2041-8213/ae157c (linked elsewhere, here again for convenience).