COMMISSION 27 OF THE I. A. U.
        INFORMATION BULLETIN ON VARIABLE STARS
                     NUMBER 286

                                    Konkoly Observatory
                                    Budapest
                                    1968 June 22


                    DH CARINAE


Andrews (1) has reported photographic photometry of DH Car in two colors (blue
and ultraviolet). As he pointed out from Hertzsprung's (2) identification
chart it was not quite clear which star did flare. Thus, before knowing the
work of Andrews, we undertook the task of observing in the UBV-system some
stars in the vicinity of DH Car as identified by Hertzsprung (2). Our first
attempt was made in 1967 at the Cerro Tololo Inter-American Observatory with
the 16-inch telescope. The results of these observations indicated that DH Car
should be earlier than M0 and fainter than V=13 mag. Our second attempt was
made at the same observatory with the 36-inch telescope. The results are
listed in Table I. The first column gives the designation in Fig. 1, The a,
b, and f stars are those given by Andrews (1) (also DH Car). From second to
last column is our photometry with the mean errors and the number of
independent observations.

Table I.

Photometric Results

          V        m.e.     (B-V)    m.e.     (U-B)    m.e.      n
DH Car  15.^m46  +-0.^m03   0.^m90  +-0.^m03  0.^m32  +-0.^m09   27
a       12.83    +-0.04     0.91    +-0.01    0.05    +-0.05      2
b       14.3     +-0.1      0.9     +-0.1     0.8     +-0.1       2
f       15.2     +-0.2      0.82    +-0.09    0.3     +-0.2       6
h       12.76    +-0.01     0.92    +-0.01    0.35    +-0.04      2
i       13.07    +-0.01     0.93    +-0.01    0.29    +-0.04      2
j       13.25    +-0.03     0.96    +-0.01   -0.03    +-0.01      2
k       16.3     +-0.2      0.87    +-0.01    0.16    +-0.06      5

We should mention that our technique consisted of eight seconds integration
time to be able to detect rapid light variations, if any. During our observing
run (March 25, 26, 27; 1968; U.T.) we had a set of much higger deflexions,
possibly caused by a flare. The results of this "flare" are listed in Table
II. The columns give first, the Julian Day, and from second to last, the
increase in brightness in V, B, and U respectively. Notice that these figures
are several times the mean errors listed in Table I.

Table II

A Possible Flare of DH Car

          J.D.
2439942.0 +        Delta V    Delta B     Delta U
0.^d529-0.^d536     0.^m17     0.^m63      1.^m00

If DH Car is not strongly affected by interstellar extinction its spectral type
is around K2.

We also took two 103a-O plates centered on DH Car of high quality with the
38-inch telescope. They show clearly a faint companion, less than two seconds
of arc apart from DH Car (mostly to the West). The probability that they form
a physical system is high because flare stars very often belong to double
systems (3).

The author thanks to Dr.E.E. Mendoza for his advise and suggestions.

                          [FIGURE 1]




Astronomy Department, University of Chile and Cerro Tololo Inter-American
Observatory.
June 13, 1968.
                                                     S. TAPIA

References:

1) A.D. Andrews, I.B.V.S. No 248 (1968)
2) E. Hertzsprung, B A.N. Vol. 2, 87 (1924)
3) L.H. Solomon, Smithsonian Ap. Obs. Special Report No 210, 4 (1966).