COMMISSION 27 OF THE I.A.U.
                 INFORMATION BULLETIN ON VARIABLE STARS
                             Number 3247

                                                         Konkoly Observatory
                                                         Budapest
                                                         4 October 1988

                                                         HU ISSN 0374 - 0676


     A NEW RAPIDLY OSCILLATING Ap STAR IN THE NORTHERN HEMISPHERE

We monitored the star HD 176232 (HR 7167; 10 Aqr), classified as an
F0p, photometrically for a total of ~29 hours over a period of 8 days during
July 1988. We detected a low amplitude light variation with a period of
approximately 11.5 minutes. This is equivalent, within the errors, of the
period detected in July 1987 (Heller and Kramer 1988) and confirms the
suspected variability. There are also indications that other frequencies may
be present.
   We obtained high speed photometric observations of HD 176232 using
the one-meter telescope and single channel photometer of the Mount 
Laguna Observatory (MLO), jointly operated by San Diego State University
and the University of Illinois. A series of continuous 20-second integrations
were taken through a Johnson B filter and 40 arc sec diaphragm; interrupted 
only for occasional sky measurements and recentering at irregular
intervals. The equipment and reduction of the data are described in Heller
and Kramer (1988). We computed the amplitude spectrum using Deeming's 
(1975) algorithm along with the time saving schemes of Kurtz (1985),
and O'Donoghue and Warner (1982). All amplitudes reported are semi-
amplitudes.
   Figure 1 shows an amplitude spectrum of the combined one-meter data.
A peak rising above the noise level at approximately 1.45 mHz dominates
the periodogram with an amplitude of 0.42 mmag. An excess of power at
nearby frequencies can be seen in the figure and may indicate the presence
of other variations in HD 176232.
   We are currently reducing an additional ~90 hours of photometric data
taken with the 61-cm telescope at MLO in June and July 1988. The full
data set spans some 60 days. Unfortunately, because of the smaller mirror
diameter of the 61-cm telescope, the scintillation noise is significantly
larger than with the 1-meter.
   We feel there is strong evidence for rapid light variation in HD 176232.
While the presence of other frequencies are suggestive by the preliminary
investigation, a full analysis of the entire data set is necessary before this
can be stated with confidence. Further analysis of the data is currently in
progress.
   We acknowledge Steven Kawaler for reviewing this manuscript.


                              [FIGURE 1]

 Figure 1: An amplitude spectrum of data taken between JD2447351 and
 JD2447359 for HD 176232. The highest peak is at 1.45 mHz (11.5 min)
 and has a semi-amplitude of 0.42 mmag.



                     CLAYTON H. HELLER

                   Department of Astronomy
                       Yale University
                   New Haven, CT 06511 USA

                     KAREN S. KRAMER

                  Mount Laguna Observatory ^1
                 San Diego State University
                  San Diego, CA 92182 USA



References:

Deeming, T. J. 1975, Ap. Space Sci., 36, 137. [BIBCODE 1975Ap&SS..36..137D ]
Heller, C. H. and Kramer, K. S. 1988, P.A.S.P., 583, 100. [BIBCODE 1988PASP..100..583H ]
Kurtz, D. W. 1985, M.N.R.A.S., 213, 773. [BIBCODE 1985MNRAS.213..773K ]
O'Donoghue, D. E. and Warner, B. 1982, M.N.R.A.S., 200, 563. [BIBCODE 1982MNRAS.200..563O ]


^1 Visiting astronomer