COMMISSION 27 OF THE I. A. U.
           INFORMATION BULLETIN ON VARIABLE STARS
                      Number 3170
                                 
                                       Konkoly Observatory
                                       Budapest
                                       30 March 1988

                                       HU ISSN 0374-0676

            THE LAST MAXIMA OF HR 8752 = V509 Cas

  Much interest in the light and spectrum variability of the hypergiant
HR 8752 = V509 Cas has recently been shown, particularly since there is 
speculation that the cause of the changes is non-radial pulsation. Sheffer and 
Lambert (1987) have determined that this pulsation may be bimodal with a dominant
mode of approximately 421 days and a secondary of 315, both of which may be
overtones of a primary fundamental mode of 1070 days. Concerted efforts by
photometrists (e.g., Mantegazza et al., 1988; Zsoldos, 1986; Halbedel, 1985,
1986) have provided relatively complete coverage of the recent light variations
of this star. It has been interesting to note that while the average magnitude
of HR 8752 has remained essentially constant over the past decade, the B-V
colors have consistently become more blue with time, implying that there has
been an effective temperature increase of about 800 K over that time period.
  This paper reports on the most recent behaviour of this interesting hypergiant.
Observations at the Corralitos Observatory have now followed HR 8752
through four maxima. The observations in BV colors have been carried out with
the single channel photon-counting photometer and uncooled EMI 9924A 
photomultiplier tube. The comparison star HR 8761 (V=6.20;B-V=+1.50) and its check
HR 8778 (V=6.43; B-V=+0.90) have remained constant throughout this time period
to within 0.01 in V magnitudes and 0.02 in B-V.
  The thusfar unpublished Corralitos magnitudes are shown in Table I, and
graphically depicted for the entire four year span in Figure 1. It is 
interesting to note that the last maximum of HR 8752 was somewhat depressed in
V magnitude and that the trend towards bluer colors has most definitely
continued.
  Two spectra centered on H-alpha were also obtained by the author with the
Kitt Peak Observatory coude feed telescope and CCD camera on JD 2447119.6715
and 7120.6819. These showed the same profile at H-alpha as has been previously
observed by others for this stars a double peaked emission line with deep
central absorption superimposed on a wider absorption. Mean radial velocity
measures of these features and a superposition of the line profiles revealed
no detectable change from night to night. The radial velocities appear in
Table II and the line profile in Figure 2.

                        Table I

       JD-2440000 V      B-V          JD-2440000 V      B-V
       6710.6868 4.92   +1.24         7038.7777 5.01   +1.27
       6713.7958 4.88    1.25         7045.8340 5.03    1.29
       6714.7826 4.88    1.23         7046.7993 5.01    1.29
       6717.7277 4.88    1.23         7047.8201 5.03    1.26
       6730.7805 4.91    1.21         7049.7507 4.97    1.27
       6732.7395 4.88    1.25         7050.8438 4.98    1.25
       6735.6847 4.87    1.22         7051.7021 4.99    1.25
       6754.6062 4.90    1.29         7062.7750 4.96    1.24
       6755.6548 4.91    1.25         7066.7826 4.98    1.23
       6756.7381 4.95    1.25         7067.6875 4.97    1.22
       6759.6111 4.84    1.24         7087.7194 4.95    1.21
       6773.6326 4.91    1.21         7088.7528 4.96    1.20
       6774.6145 4.94    1.19         7089.6271 4.94    1.21
       6776.6125 4.95    1.23         7102.7451 4.92    1.21
       6777.5784 4.93    1.23         7106.6965 4.90    1.21
       6794.6263 5.01    1.19         7124.6819 4.91    1.17
       6795.5951 5.02    1.26         7125.6806 4.90    1.17
       6797.5770 4.99    1.24         7126.6271 4.90    1.17
       6800.5909 4.99    1.25         7127.6340 4.91    1.17
       6814.5784 5.00    1.30         7128.6229 4.90    1.18
       6817.5826 5.00    1.30         7169.5771 4.88    1.16
       6945.9424 4.99    1.13         7170.5868 4.86    1.17
       6948.9479 4.97    1.20         7173.5785 4.91    1.12
       6949.9417 4.98    1.20         7174.5785 4.91    1.10
       6951.9076 4.99    1.20         7175.5861 4.96    1.15
       6994.8465 4.97    1.22


                              [FIGURE 1]

 Figure 1. V and B-V observations for HR 8752 for the past four
           observing seasons.


                  Table II

       H-alpha feature mean radial velocities:
       Violet Emission Peak            -134.7 km s^-1
       Line Profile center             - 98.2
       Deepest Absorption              - 94.0
       Red Emission Peak               - 49.0

       Mean stellar radial velocity:

       -43.7 +/- 5.9 km s^-1 (from 7 lines)


                            [FIGURE 2]

            Figure 2. Mean H-alpha line profile for HR 8752.




                         E.M. HALBEDEL
                         Corralitos Observatory
                         P.O. Box 16314
                         Las Cruces, NM 88004
                         USA

References:            

Halbedel, E.M., 1985, Inf.Bull.Var.Stars, No. 2718
Halbedel, E.M., 1986, Inf.Bull.Var.Stars, No. 2876
Mantegazza, L., Poretti, E., and Antonello, E., 1988, Inf.Bull.Var.Stars, No. 3137
Sheffer, Y., and Lambert, D., 1987, Publ.Astr.Soc.Pacific, 99, 1277 [BIBCODE 1987PASP...99.1277S ]
Zsoldos, E., 1986, Inf.Bull.Var.Stars, No. 2913