COMMISSION 27 OF THE I. A. U.
             INFORMATION BULLETIN ON VARIABLE STARS
                         Number 3611    

                                                Konkoly Observatory
                                                Budapest
                                                28 May 1991

                                                HU ISSN 0374 - 0676


     THE DISCOVERY OF RAPID OSCILLATIONS IN THE Ap STAR HD 119027


The star HD 119027 was observed for 5.0 hr on the night JD 2448377 as part of
the Cape Rapidly Oscillating Ap Star Survey. Inspection of the real-time data
display at the telescope revealed the presence of rapid oscillations with a
period P=8.63 min and an amplitude A=1.8 mmag (Fig. 1). The observations were
acquired with the University of Cape Town photometer attached to the 1.0-m
Elizabeth telescope of the South African Astronomical Observatory at
Sutherland. The data comprise continuous 10-s integrations through a Johnson B
filter with occasional interruptions for measurements of the sky background.

The data were corrected for coincidence-counting losses, sky background and
extinction, in that order. We then removed some gradual (T>0.5 hr) sky
transparency variations and binned the data to 40-s integrations. The light
curves were then Fourier analyzed individually and as a group.


                             [FIGURE 1]
                             [FIGURE 2]


The amplitude spectrum of the data acquired on night JD 2448377 is presented in
the upper panel of Fig. 2. The prominent peak is at nu_1=1.93 mHz. We
observed this star again on the following two nights, JD 2448378 & 8379, and the
amplitude spectra of those two nights are shown in Fig. 2 in the middle and
lower panel, respectively. We also Fourier analyzed the three nights together
to refine our determination of nu_1 to nu_1=1.9302 mHz.

Note that the height of the peak nu_1 differs among the panels by somewhat more
than the level of the noise. This suggests that the oscillations in HD 119027
are amplitude modulated on a timescale of ~1 day. We are unable to investigate
the nature of this modulation with that data currently at hand. Further
observations of this star are scheduled and a detailed frequency analysis will
be presented in a future publication.


PETER MARTINEZ & D.W. KURTZ
Dept of Astronomy
University of Cape Town
Rondebosch, 7700
South Africa
PETER%UCTVAX%QUAGGA@UUNET.UU.NET
DKURTZ%UCTVAX%QUAGGA@UUNET.UU.NET