The Astrophysical Journal · 1973 · 10 citations · 0 references
Natural SciencesAstronomyPhysicsAstrophysicsOptical AstronomyX-ray AstronomyX-ray BinariesX-ray Source CatalogsMass Ratio DeterminationPhotometryTransient X-ray Sources
The variability of Sanduleak 160, the proposed optical counterpart of SMC X-l, has been confirmed. It shows a double-peaked optical variation with the minimum at X-ray eclipse being the deeper. The cos 20 variation has a semiamplitude of 0.050 mag in the B filter, the cos 0 variation has a semiamplitude of 0.025 mag, and there is a cos 30 variation of 0.012 mag semiamplitude. From an analysis of the optical photometry and X-ray eclipse duration the mass ratio is found to be 0 28 i - 79 and P - 3.89206 days. On the assumption that the mass of Sk 160 is 20 M0, the mass of SMC X-l is 5.6 M0. Subject headings:binaries - black holes - Magellanic Clouds - X-ray sources