COMMISSIONS 27 AND 42 OF THE IAU
            INFORMATION BULLETIN ON VARIABLE STARS
                         Number 4040


                                              Konkoly Observatory
                                              Budapest
                                              16 June 1994

                                              HU ISSN 0374 - 0676


               NON-CEPHEID CHARACTER OF V588 Cas

  V588 Cas (RA=1h19m12s, Dec=+54d6', 1950.0) is listed in the 4th Edition of the
GCVS as "DCEP:" with no period or epoch given. The magnitude range is listed as
12.2m-13.6m (photographic). We observed V588 Cas during January-March in 1992 and
1993, included in our list of Cepheids thought to have few or no recent observations. We
found no indication of a Cepheid light curve.
  The GCVS lists a reference for a finder chart (Hoffmeister, 1957), which has been
reproduced in Figure 1. Although no chart on the No. 291 page is labelled as V588 Cas,
we recognize the field, in comparison with our CCD images (our telescopes point to 30"
or better). The MVS chart is labelled "S3880 Cas".
  A printout of one of our R-bandpass CCD images is shown in Figure 2, for comparison
with Figure 1. Our field of view in this image is about 5 arc minutes. We have 
assigned arbitrary star numbers and the variable marked in the MVS is #1 on our diagram.
Agreement of our field with this MVS chart is not in doubt.
  We obtained CCD observations during the 1992 and 1993 observing seasons to check
the light curve of this star. We used two similar telescopes and CCD equipment, at two
sites. RHB obtained observations with the U.S. Air Force Academy's 0.4 m DFM Engineering 
reflector, and a 14-bit Photometrics (LN_2-cooled) CCD system. DLD obtained
observations with Virginia Military Institute's 0.5 m DFM Engineering reflector, and a
14-bit Photometrics (Peltier-cooled) CCD system.
  Observations were obtained in the Johnson V and R bandpasses, with a field of view of
12', and 5', respectively, for the two systems. Standard flat field corrections were applied
to all V588 Cas images. We obtained images of the standard field in M67 (Schild, 1983),
to insure that our detector/filter system was close to the standard Johnson system. We
used DAOPHOT (VMI) or rectangular aperture photometry (USAFA) to obtain magnitudes 
from the corrected CCD images. Observations were entered into a spreadsheet, with
comparison star differences tabulated to help insure that any errors would be noticed.


                               [FIGURE 1]
                               [FIGURE 2]

                               [FIGURE 3]

                Figure 3. Light curve of V588 Cas (1993 data)


  Unlike the other Cepheids observed, we found that V588 Cas does not show any indication 
of a Cepheid light curve. In Figure 3 is shown our differential R bandpass CCD
observations of V588 Cas, referenced to the average magnitude of comparison stars #2
and #3 (squares=VMI data, triangles=USAFA data). In the bottom half of the graph
is shown magnitude differences of comparison stars #2 and #3 (with an offset to place
the difference conveniently on the graph), as an indication of the variability and 
observational noise in these comparison stars. We found that the average of our comparison
star differences (VMI-USAFA) showed an 0.031m difference, and we added that amount
to one set to insure no systematic differences; that difference might be attributed to the
different manner of obtaining magnitudes.
  The standard deviation of the differences (shown on the graph) of the comparison stars
(#2 minus #3) is 0.016m. For the variable minus the average of the two comparison stars,
the standard deviation is 0.021m. The variation in the variable star is comparable to that
in the comparison stars. Although only our 1993 results are shown, we obtained similar
results with the 1992 data.
  We examined the surrounding stars out to about 4' (radius) for variability above the
0.1m level, and found none. The CCD photometry, using images, greatly reduces the risk
of misidentification. We conclude that the star denoted as V588 Cas is not a Cepheid.


David L. DuPUY                Raymond H. BLOOMER
Dept. Physics & Astronomy     Dept. of Physics
Virginia Military Institute   King College
Lexington, VA 24450           Bristol, TN 37620
(dupuydl%physics%vmi@
ist.vmi.edu)



References:
Hoffmeister, C., 1957, Mitt. Ver. Sterne, No. 291
Schild, R., 1983, Publ. Ast. Soc. Pac., 95, 1021 [BIBCODE 1983PASP...95.1021S ]