COMMISSION 27 OF THE I.A.U.
                 INFORMATION BULLETIN ON VARIABLE STARS
                              Number 2931

                                                         Konkoly Observatory
                                                         Budapest
                                                         8 September 1986

                                                         HU ISSN 0374 - 0676


              PHOTOELECTRIC LIGHT CURVES OF TY BOOTIS

The eclipsing binary system TY Boo was discovered by Guthnick and
Prager (1926). Carr (1972) published the first photoelectric light curves
and determined seven times of minimum light. He attempted a Russel-Merrill
solution of the system but stated that nonrectifiable distortions in this
W Ursae Majoris-type light curve limited the accuracy of his results. One
subsequent photoelectric minimum has been determined (1982) since Carr's
observations.
   The present observations of TY Boo were made on five nights during
June, 1986. The 31 inch F/16 telescope at Lowell Observatory was used with
standard B, V filters and a thermoelectrically cooled EMI 6256 photomultiplier.
The comparison and check star were those designated by Szafraniec (1953) as
"f" and "g" respectively. The positional information is given in Table I.
Neither TY Boo, nor the check or comparison star, has a catalogue 
identification. Approximately 350 observations were obtained at each effective
wavelength.

                      Table I

           STAR       R.A.        Dec.
                     (1950)      (1950)

          TY Boo    14h58m47s    35d19.8'
        Comparison  14h58m54s    35d16.1'
           Check    14h58m05s    35d22.0'

   Four epochs of minimum light were determined from the observations
made during two primary and two secondary eclipses using the Hertzsprung
technique (1928). These are given in Table II.


                        [FIGURE 1]

   Fig. 1 - Light curve of TY Boo defined by the individual observations.


                 Table II

JD Hel
2446500+   Minimum   Cycles      (O-C)

87.7281      II       -6.5      -0.0011
88.8392       I       -3.0      -0.0000
89.7908       I        0.0      -0.0000
91.8510      II        6.5      -0.0012

These four minima along with the eight other photoelectric minima were
introduced with varying weights into a least squares solution to obtain the
following improved ephemeris:

           JD Hel Min.I= 2446589.7907  +0d.31714964E
                                  +-5           +-3 (p.e.)

   This emphemeris was used in calculating the O-C's in Table II.
   The B and V light curves of TY Boo defined by the individual observations 
are shown in Figure 1 as delta m versus phase. The analysis of the
observations is underway.


                       RONALD G. SAMEC
                     BEVERLY B. BOOKMYER

                   Dept. of Physics & Astronomy
                       Clemson University
                   Clemson, SC 29634-1911 USA



References:

BAV 34 (1982)
Carr, R. B. 1972, Astron. J. 77, 155. [BIBCODE 1972AJ.....77..155C ]
Guthnick, P., and Prager, R. 1926, Astron. Nachr. 228, 99. [BIBCODE 1926AN....228...99G ]
Hertzsprung, E. 1928, Bull, Astron. Inst. Neth. 4, 179. [BIBCODE 1928BAN.....4..178H ]
Szafraniec, R. 1953, Acta Astron. Ser. b, 2, 100.