3RD LIGHT IN THE SOLUTION OF AN ECLIPSING BINARY LIGHT-CURVE - V505-SAGITTARII

Recent spectroscopic and speckle-interferometric observations made by separate observers have established the existence of a tertiary compon ent in the V505 Sagittarii system. V505 Sgr has been observed and stud ied many times since its discovery in 1934, but the light of the third component l3 has never been detected in light curve solutions. In the present study the SIMPLEX algorithm [Kallrath & Linnell, ApJ, 313, 34 6 (1987)] and the Differential Correction (DC) code [Wilson, ApJ, 234, 1054 (1979)] were used to analyze, for the first time, data obtained by Walter [A&AS, 46, 263 (1981)]. The solutions reveal l3 contributing 7 percent light in the V bandwidth, 5 percent in B, and 4 percent in U. These relative intensities correspond to a star with an F8 V spectr um. Tomkin [ApJ, 387, 631 (1992)] obtained F7 V for the third componen t from his spectroscopic investigation. The photometric mass ratio (q = 0.52) also agrees with Tomkin's study. A comparison between the SIMP LEX and DC solutions is presented.