COMMISSION 27 OF THE I. A. U.
        INFORMATION BULLETIN ON VARIABLE STARS
                    Number 2120

                               Konkoly Observatory
                               Budapest
                               1982 March 31

                               HU ISSN 0374-0676



         OBSERVATIONS OF EARLY-TYPE ULTRA-SHORT
                  PERIOD VARIABLES




   Jakate (1979) proposed a new class of early-type ultra-short period
variables from observations of four B2V and B3IV stars. Their periods are
an hour or less and their light amplitudes between 0.015 and 0.025 
magnitudes. Percy (1980) re-observed the only northern member of the group,
HR8768, and confirmed it to be variable with a period and amplitude
consistent with Jakate's finding. However, the range appears not to
be constant, since Percy found only marginal variability on one of the
two nights that HR8768 was observed.

It is clearly of great importance to confirm the existence of this
new group of variable stars as it may give a new insight to the nature of
beta Cep variables. For this purpose, we observed the remaining three southern
members with the 0.5m reflector of the Sutherland station of the South African
Astronomical Observatory. All observations were made through the Johnson
B filter. For HR5285 we used the comparison stars HR5294 and HR5249. For
HR3467 and HR3582 we used the comparison stars HR3568 and HR3503. The results
of five nights of observations are shown in the accompanying figures.

   It is clear that in all cases the stars are constant to within a few
thousandths of a magnitude over several hours. The reality of this group of
variables must be considered doubtful at this stage. However, further
observations of HR8768 are clearly required before a definite conclusion
can be made.

                    L. A. BALONA

                    South African Astronomical Observatory
                    P.O. Box 9
                    Observatory 7935
                    South Africa

References:         

Jakate, S.M. 1979, Astron. J. 84, 1042. [BIBCODE 1979AJ.....84.1042J ]
Percy, J.R. 1980, IBVS No. 1734.


                       [FIGURE 1]
                       [FIGURE 2]
                       [FIGURE 3]
                       [FIGURE 4]

Figs. 1, 2, 3, and 4: Observations of suspected early-type ultra-short
period variables. The tick marks are spaced at 0.02 magnitude intervals.





                        [From IBVS 2124]


                         ERRATUM


A label in the paper "Observations of Early-type Ultra-short Period
Variables" by L.A. Balona (I.B.V.S. No. 2120) is in error. This occurs in
the figures where the star labeled HR 3462 should read HR 3467.