1994A&A...289..868P

From spectral line profiles the presence of a cool polar cap has been inferred for several late-type stars; for some other similar stars the absence of a cool polar cap has been suggested. In addition, it would be surprising if a star with a cool region at one rotational pole did not have a similar cool region at the other pole. To test the detectability of cool polar caps on late type stars we have computed the effect such cool spots would have on the profile of the Ca I 6439 A. While a cool cap at the visible pole may be detected, the presence of another equivalent cap at the other pole cannot be detected with current techniques.