AAS 195th Meeting, January 2000
Session 39. Neutron Stars with Partners
Display, Thursday, January 13, 2000, 9:20am-6:30pm, Grand Hall

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[39.06] Possible Mass Constraints of Cygnus X-3

M.M. Hanson (U.\ Cincinnati), M.D. Still (NASA/GSFC), R.P. Fender (U.\ Amsterdam)

We have completed an investigation of the near-infrared spectroscopic data our group obtained as part of a two-year observational campaign of Cygnus X-3 in 1996 and 1997. We have applied Gaussian profile fits and tomographic modeling to the full phase coverage spectra to make the most accurate comparison of line profile variations matched against the X-ray phase of the system.

The June 1996 quiescent data reveal the He\,II and N\,V emission features to show maximum blue shift at \phix = 0.00 ±0.04, relative to the x-ray minimum. There is no significant difference in \phix between the HeII or NV lines seen during the quiescent phase.

The July 1997 outburst data show a moderately strong P Cygni-like profile developed in the He\,I 2.058~\mum singlet, providing the first absorption feature ever to be traced through an entire 4.8~hr orbital period of the system. The orbital phasing of this feature shows maximum blue shift occurring at \phix = -0.32 ±0.02, significantly different from any other spectral modulation previously found in Cygnus X-3. We suggest this feature is tracing the orbital velocity of the WR + compact object system. Assuming a reasonable inclination for the system, i = 60 - 80 \circ, we derive orbital solutions which constrain the mass of the WR companion between 6 and 10 M\odot and the mass of the compact object between 1.4 and 3 M\odot.

The author(s) of this abstract have provided an email address for comments about the abstract: hanson@physics.uc.edu

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