COMMISSION 27 OF THE I. A. U.
          INFORMATION BULLETIN ON VARIABLE STARS
                      Number 1742

                                  Konkoly Observatory
                                  Budapest
                                  1980 February 15


        FURTHER NOTE ON HD 219018, COMPARISON STAR TO SZ Psc


Last year a small controversy arose over whether or not HD 219018 is variable.
Jakate (1979) claimed that it is variable on a scale of about 0.1 mag, while I
could find no such variability in observations made by me in Chile 1974 (Fernie,
1979). The result is important for much previous work done on SZ Psc itself,
an interesting RS CVn binary, since HD 219018 has long been used as a
comparison star for SZ Psc.

Jakate arrived at his result by using HD 219150 as a check star, and in my note
I suggested that possibly it was this star that was variable. During the past
season, therefore, I obtained sporadic differential observations over several
months between each of these stars and a nearby bright star HR 8852. The
results in B and V are shown in Table I, each entry being the mean of four
pairs of observations.

Table I

Differential Photometry

J.D.              HD 219018-HR 8852            HD 219150-HR 8852
                Delta V       Delta B         Delta V      Delta B
 2444121.697   4.062+-.008   3.725+-.010    3.539+-.007   2.970+-.008
    4134.682   4.064+-.005   3.739+-.003    3.534+-.003   2.990+-,003
    4163.610   4.064+-.006   3.744+-.006    3.534+-.006   2.988+-.010
    4225.496   4.067+-.005   3.741+-.003    3.559+-.004   2.986+-.002
    4237.464   4.060+-.016   -              3.536+-.010   -
    4242.475   4.057+-.018   3.742+-.021    3.558+-.011   2.988+-.002
Weighted means:4.064+-.001   3.740+-.002    3.541+-.005   2.987+-.002

It is clear that there is no variability of HD 219018 exceeding a few
thousandths of a magnitude. The same is probably true of HD 219150, although
the scatter is slightly larger in Delta V, but quite comparable in Delta B.

However, in the course of this work it was discovered that HD 219150 is a
particularly interesting star with a massive uv excess, and more detailed
photometry and spectroscopy of it will be reported elsewhere (Fernie and
Bolton, in preparation). There is a suggestion that the star may be variable
at times or variable on a much longer time-scale.

Meanwhile, it seems safe to continue to use HD 219018 as the primary comparison
star for SZ Psc.


J.D. FERNIE
David Dunlap Observatory
Richmond Hill, Ontario
Canada L4C 4Y6

References:

Fernie, J.D. 1979, I.B.V.S. No. 1609
Jakate, S.M. 1979, I.B.V.S. No. 1578