The binary star SS Lac in the open cluster NGC 7209 was reported to be variable by Hoffmeister in 1921, and subsequently analyzed by both Dugan & Wright (1935), and by Wachmann (1936). In the early 1990's Zakirov & Azimov, Schiller & Milone, and Mossakovskaya all reported that eclipses had ceased, somewhere between 1935 and the early 1950s. Lehmann (1991) suggested that the orbital inclination of the binary has been decreasing at a rate of 0.18 deg/y. Spectroscopy carried out by Schiller & Milone (1995) suggested that there appeared to be no RV variation; however, high S/N and resolution RV spectroscopy by Tomaselli & Munari (1998) who used only the Balmer lines (H alpha , beta , & gamma ), has now revealed the SB2 RV curves and provided spectroscopic elements. They also present evidence of a sharp-lined 3rd component outside of the H-lines at the cluster velocity. Since, according to good practice, Schiller had omitted the broad, noisy H-lines from his Cross-Correlation analysis, this component dominated the earlier RV results. Beginning with the Tomaselli & Munari elements, we have analyzed and rephased the the radial velocity curves and are analysing available light curves from each epoch to test the hypothesis of variable inclination.
American Astronomical Society Meeting Abstracts #192
- Pub Date:
- September 1998