Solar rotation as marked by extreme-ultraviolet coronal holes

Spectroheliograms produced in the light of Fe xv lambda284 by the Goddard Space Flight Center experiment on OSO-7 are used to determine solar rotational periods for low-emission coronal hole features. From 1972 May to 1973 October, daily measures were obtained of the coronal hole area appearing at the central solar meridian. Autocorrelations of the coronal-hole-area time series in seven latitude zones provide synodic rotation periods which indicate a close to rigid rotation by such features for lag lengths of only one rotation. For latitudes below about 50degree, both the autocorrelation functions for short-lived coronal holes and analyses of more persistent features over these 18 months suggests a quadrupolar distribution of coronal hole longitudes