Two 2'2 hour series of high-resolution spectra of the rapidly rotating 09.5 V star Ophiuchi show several distinct features at the 1% level which move through the broad A6678 He I absorption line. The nature of the velocity variation is consistent with nonuniformities in stellar surface brightness being carried across the line of sight by rotation. If a narrow absorption feature, which is seen on both nights, corresponds to the same region of the star, the rotation period is 21.7 hours. If this period is correct, then the observed acceleration of the feature leads to 560 km -1 for V Sin i and 7 >c 106 km or 10 R0. for r* sin i. These correspond well with published values except that they imply i 900. Alternatively, if values of i = 550 and r* = 10 R0. are assumed, the rotation period is 19.7 hours and V sin i is 508 km s1. The profiles of the velocity variable features have been recovered by a Fourier deconvolution technique for each night. They both show a broad emission with a sharp reversal. The latter doubled in strength by the second night. The associated "spot" appears to be confined to about 1% of the visible stellar disk. Some indication of the degree of gravity darkening is given in Figure 1 based on a value of V sin i = 560km s Subject headings: line profiles - stars: early-type - stars: individual - stars: rotation
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Walker et al. (1979) studied this question.