COMMISSION 27 OF THE I. A. U.
         INFORMATION BULLETIN ON VARIABLE STARS
                     Number 1605

                                  Konkoly Observatory
                                  Budapest
                                  1979 May 15



             TWO STARS NAMED KY AQUILAE




    Dr. W.P. Bidelman recently called to my attention a confusion
in the identification of KY Aql. At Harvard in 1932 I had discovered 
a star provisionally called HV 5429, 14.3 - 15.5pg. This is the
star first assigned the designation KY Aql, and the corresponding
data were included in the GCVS through the 1958 editions. Then
Gessner (1958) discovered another variable close to this one and
mistakenly assumed it to be KY Aql, even though she, herself, pointed 
out that her results did not substantiate mine. Bidelman noted
that the position of an infrared source, which does appear to be
the star that Gessner discovered, is about 1.3' north and 2 sec west
of the position I gave. Figure 1 shows the relative positions of
the two variable stars.                     

                        [FIGURE 1]

 Figure 1. Finder chart, about 10' x 10', for the two stars called
 KY Aquilae. A = HV 5429; B = variable discussed by Gessner.

    In my original publication I had indicated that HV 5429
might be a short period variable; indeed a period of 0.5023 day
seemed promising although not quite acceptable. This result, however, 
must be considered as spurious. Some 50 plates of the MC
series (16-inch Metcalf telescope) and only six MF (10-inch Metcalf)
and 5 B (8-inch Bache) were available, all within the interval
1926-31. The basis for the assumption of the short period was that
a maximum on an MC plate fell between two minima on the MF. Later
I established that the color transmission of the MF is different
from that of most of the other Harvard lenses: there is a sharp
cut-off to the red of Hbeta for the MF. Thus, if either the variable
or one of its comparison stars is red, then there may well be 
systematic errors between the estimates made from the different plate
series. Figure 2 shows the bulk of the observations on the MC
plates alone. This suggests a probably irregular variable.

                         [FIGURE 2]

 Figure 2. Observations of HV 5429 from JD 26100 to 26700; markers
 at intervals of 100 days. Ordinates, photographic magnitudes at
 intervals of 0.5 mag.

According to Bidelman this star does not have a late-type spectral
class.

  The question now is, which of the two variable stars is to
retain the designation, KY Aquilae?





                       DORRIT HOFFLEIT

                       Department of Astronomy
                       Yale University
                       New Haven, Conn. 06520
                       U.S.A.


References:
Bidelman, W.P. 1978, Private communication
Gessner, H. 1958, Mitt der Veranderlichen Sterne, Sonneberg, Nr. 366
Hoffleit, D. 1932, Bull. Harvard Coll. Observatory, No. 887, p. 9 [BIBCODE 1932BHarO.887....9H ]