PEERING OVER THE SUNS POLE - BEHAVIOR OF ITS ROTATIONAL VORTEX

A new method for measuring spectroscopically the rotation at the Sun's poles is described. Using solar CO lines at 4.666 mu m, infrared spec tra are recorded at a fixed limb distance of 4.8 are sec while progres sing along an are +/-5.7 deg from the Sun's rotational pole. Since the poles dip twice a year to about 7 are sec from the limb, our observat ions can range either side of and through the vortex axis. Advantages to this technique are: (1) a low disturbing signal from supergranules owing to their superposition at the limb, (2) no 'limb shift' error si nce limb distance is constant and the CO lines have no known limb shif t, (3) emphasis is on the quiet Sun since the CO molecule is confined there, (4) negligible scattered light in the IR (<1%), and (5) the imp roved seeing afforded by the IR. Although any definitive determination of solar rotation requires observations over an extended time span, o ur preliminary results suggest two features peculiar to the extreme po le: (1) the occasional apparent cessation of rotation, (2) some sort o f singularity again occasional, producing a sharp velocity signal (a v ortex?) within 1 deg of the pole.