COMMISSION 27 OF THE I. A. U.
         INFORMATION BULLETIN ON VARIABLE STARS
                     Number 1593

                                 Konkoly Observatory
                                 Budapest
                                 1979 April 28




 PHOTOELECTRIC PHOTOMETRY OF THE DELTA SCUTI STAR HD 4818


 HD 4818 has been observed in November 1978 at the Merate 
Observatory in the framework of the photoelectric researches on
Delta Scuti stars (Guerrero et al., 1979). This star has been
found variable by Bhatnagar (1973) with period equal to 0.1360d
and light amplitude of 0.025m+-0.01.
  We observed HD 4818 for three nights in V light: comparison
and check stars were HD 4881 and HD 6028, respectively. The 
results are represented in the Figure: each point is the mean of
about eight individual observations (variable minus comparison)
and the bars represent two standard errors.
  To search for multiple periodicity, these data were then 
analysed with the Vanicek method (1971). Two sinusoidal component
were found unambiguously: P_1=0.0526d and P_2 =0.0396d with the 
semiamplitudes: A_1 =0.0018m+-0.0006 and A_2 =0.0028m+-0.0005. Though these
amplitudes are very small, the statistical significance of these
peaks in the spectrum against random noise is of 96% and 99.4%
respectively.
  The ratio between the two periods, i.e. (P_2/P_1)=0.753 suggests
that radial pulsational modes are working in HD 4818 (Petersen
et al., 1972).




                 G. GUERRERO, L. MANTEGAZZA, M. SCARDIA
                 Osservatorio Astronomico di Brera
                     20121 Milano, Italy




References:

Bhatnagar, A.K., Gupta, S.K. 1973, Inf. Bull. Var. Stars, No. 778
Guerrero, G., Mantegazza, L., Scardia, M. 1979, Astron. and
    Astrophys. Suppl., in press [BIBCODE 1979A&AS...38..181G ]
Petersen, J.O., Jorgensen, H.E. 1972, Astron. and Astrophys. 17, 367 [BIBCODE 1972A&A....17..367P ]
Vanicek, P. 1971, Astrophys. Spa. Sci., 12, 10 [BIBCODE 1971Ap&SS..12...10V ]


                      [FIGURE 1]