COMMISSION 27 AND 42 OF THE IAU
                   INFORMATION BULLETIN ON VARIABLE STARS
                               Number 3848

                                                         Konkoly Observatory
                                                         Budapest
                                                         26 February 1993

                                                         HU ISSN 0374 - 0676


                     RECENT UBVR MAGNITUDES FOR RHO Cas

Rho Cas is a yellow hypergiant that undergoes both pulsation and mass-loss
episodes accompanied by complex spectrum and photometric changes. Zsoldos &
Percy (1991) have found an underlying significant period of 298.5 days which
has remained constant for nearly three decades.
   Photometrically, Rho Cas has been well observed. Its light variations are
semi-regular in nature with occasional deep minima which are likely associated
with the mass-loss events  This paper continues a series of observations of
this star. All data were obtained utilizing the 0.6-m telescope of the
Corralitos Observatory and two photometric systems, one based on an EMI 9924A
tube and the other on an R4457, both ambient temperature. Considerable care
was taken in insuring that sufficient standard stars were observed so as to
maintain consistency in magnitude and colors between the two systems. In
previous papers (Halbedel, 1988, 1991), two comparison stars were utilized:
Tau Cas and HR 9010. However, in the last two observing seasons, Tau Cas has
been found to be brighter than normal (Halbedel, to be published). Therefore,
it has been dropped as a comparison star for the Rho Cas magnitudes of the last
two observing seasons. However, Tau Cas has remained stable enough over the
previous years of observing to allow the previously cited Rho Cas magnitudes to
continue to be valid. For the most recent magnitudes of Rho Cas (which appear
in Table 1), only HR 9010 (V=5.510; B-V=+1.650; U-B=+1.810; V-R=+1.290) is
used as a comparison. In the future, another comparison star will be added in
order to unambiguously insure that HR 9010 is nonvariable.
   Figure 1 shows a composite light curve for Rho Cas. It incorporates data
from all recent sources: Halbedel (1988, 1991, and this paper), Leiker & Hoff
(1987, 1990), Leiker, Hoff, Nesbella et al. (1988), Leiker, Hoff, & Milton
(1989), Leiker, Hoff, & Caruso (1991), and Zsoldos & Percy (1991). There
is surprisingly little scatter when one considers the multiplicity of sources
used. The behavior of the star is essentially unchanged: it still undergoes
semiregular variations, though the most recent increase in mean magnitude has
ceased and the star is reddening again. At present, there are too few U-B and
V-R magnitudes to delineate a trend in those colors. Rho Cas will continue to
be observed indefinitely at the Corralitos Observatory.

   The author would like to most gratefully acknowledge a Theodore Dunham, Jr.
grant of the Fund for Astrophysical Research for purchase of photometric
equipment.


                              [FIGURE 1]

 Figure 1. Magnitudes and colors for Rho Cas. The top diagram shows V, 
 the bottom B-V. Julian Date is JD - 2440000.


                   Table I
             UBVR magnitudes for Rho Cas
Since only one star was used for comparison purposes,
        there are no standard errors

JULIAN DATE       V        B-V     U-B      V-R
(2440000+)

8532.78611      4.429    +1.192
8535.74861      4.434     1.184
8546.70833      4.417     1.155
8562.69444      4.404     1.164
8597.67292      4.413     1.166
8620.59583      4.353     1.138
8636.59028      4.342     1.126
8637.59236      4.343     1.144
8800.93056      4.550     1.286
8842.89306      4.606
8898.78958      4.620     1.318   +1.190   +1.176
8901.75347      4.618     1.322    1.211    1.167
8932.77292      4.586     1.349    1.268    1.161
8951.70903      4.600     1.347    1.259    1.196
8973.65694      4.579



                                       ELAINE M. HALBEDEL
                                       Corralitos Observatory
                                       P.O. Box 16314
                                       Las Cruces, NM
                                       U.S.A. 88004



References:

Halbedel, E. M., 1988, IBVS, No. 3171.
   1991, IBVS, No. 3616.
Leiker, P.S. & Hoff, D.B., 1987, IBVS, No. 3020.
   1990, IBVS, No. 3490.
Leiker, P.S., Hoff, D.B., & Caruso, J.R., 1991, IBVS, No. 3639.
Leiker, P.S., Hoff, D.B., & Milton, R., 1989, IBVS, No. 3345.
Leiker, P.S., Hoff, D.B., Nesbella, J., Gainer, M., Milton, R., & Pray, D.,
   1988, IBVS, No. 3172.
Zsoldos, E. & Percy, J.R., 1991, AAp, 246, 446. [BIBCODE 1991A&A...246..441Z ]