Radial Velocity Curves Of 4U1700-377
Abstract
4U 1700-377 is an eclipsing X-ray binary containing a high mass O6Iaf star paired with a compact object. Recent estimates have placed the mass of the compact object at around 2.4 solar masses, which if confirmed, would indicate that 4U 1700-377 contains either the most massive neutron star known or the least massive black hole known. We present high resolution, high signal-to-noise echelle spectra of 4U 1700-377 obtained with the MIKE spectrograph on the 6.5m Magellan Clay Telescope at Las Campanas Observatory. Radial velocity curves were obtained from measuring individual lines and from a cross correlation analysis using several lines at once. The radial velocities show considerable scatter about the mean, possibly due to the strong stellar wind. In addition, the radial velocity curves are not sinusoidal, probably due to a combination of a slightly eccentric orbit and relatively large corrections to the velocity curve owing to the distorted nature of the star (e.g. Wilson and Sofia 1976, ApJ, 203, 182). We present models of the radial velocity curves based on Roche geometry and discuss the implications for the mass of the compact object.
- Publication:
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American Astronomical Society Meeting Abstracts #215
- Pub Date:
- January 2010
- Bibcode:
- 2010AAS...21541905R