COMMISSION 27 OF THE I. A. U.
                 INFORMATION BULLETIN ON VARIABLE STARS
                             Number 3539

                                                       Konkoly Observatory
                                                       Budapest
                                                       8 November 1990

                                                       HU ISSN 0374 - 0676


          An independent confirmation of rapid oscillations
                 in the cool Ap star HD 12932

   The V=10.3 Ap star HD 12932 is classified as Ap SrEuCr by Houk and
Smith-Moore (1988), making it a good candidate for rapid oscillations. Weiss
and Schneider 1990 (private communication and I.B.V.S., submitted) have just
discovered it to be a rapidly oscillating Ap (roAp) star; in this bulletin, I
report an independent confirmation of the detection of rapid oscillations.
   Photometry was obtained on three nights in Oct. 1990 with the Lowell 1.1-m
John S. Hall telescope and the 0.8-m reflector in Johnson B. A total of over
7 hours of photometry was obtained over a time-span of 7 days. A periodicity
analysis of the data was undertaken utilizing Kurtz' (1985) faster algorithm of
the Deeming (1975) DFT technique. The figure shows a peak in the amplitude
spectrum near 124 c/d (nu=1.44 mHz), corresponding to a period of about 11.6
minutes. A least-squares cosine fit to the data yields a best fit to the
period 11.605+/-0.003 minutes, with a semi-amplitude of 2.27 millimagnitudes.
   I gratefully acknowledge the Lowell Observatory endowment for support of
this research.


                               [FIGURE 1]




                                            TOBIAS J. KREIDL
                                            Lowell Observatory
                                            Mars Hill Rd., 1400 West
                                            Flagstaff, AZ 86001, U.S.A.



References:

Deeming, T.J., 1975. Astrophys. Space Sci., 36, 137. [BIBCODE 1975Ap&SS..36..137D ]
Houk, N., Smith-Moore, M., 1988. Michigan Spectral Catalogue,
   Vol. 4, Department of Astronomy, University of Michigan, Ann Arbor. [BIBCODE 1988mcts.book.....H ]
Kurtz, D.W., 1985. Mon. Not. R. astr. Soc., 213, 773. [BIBCODE 1985MNRAS.213..773K ]


* The discovery note has been published by Schneider and Weiss in the
  No. 3520 issue of the I.B.V.S. (Editors). [IBVS 3520]