DSS Images Other Images
|The mass of X-ray Nova Scorpii1994 (=GRO J1655-40)|
We have obtained high- and intermediate-resolution optical spectra ofthe black hole candidate Nova Scorpii 1994 in 1998 May/June, when thesource was in complete (X-ray) quiescence. We measure the radialvelocity curve of the secondary star and obtain a semi-amplitude ofK_2=215.5 +/- 2.4 km s^-1, which is 6 per cent lower than the onlypreviously determined value. This new value for K_2 thus reduces thebinary mass function to f(M) = 2.73 +/- 0.09 M_solar. Using only thehigh-resolution spectra, we constrain the rotational broadening of thesecondary star, v sin i, to lie in the range 82.9-94.9 km s^-1 (95 percent confidence) and thus constrain the binary mass ratio to lie in therange 0.337-0.436 (95 per cent confidence). We can also combine ourresults with published limits for the binary inclination to constrainthe mass of the compact object and secondary star to the ranges 5.5-7.9and 1.7-3.3 M_solar respectively (95 per cent confidence). Finally, wereport on the detection of the lithium resonance line at 6707.8 Å,with an equivalent width of 55 +/- 8 m Å.
|Radial velocities of southern stars obtained with the photoelectric scanner CORAVEL. III - 790 late-type bright stars|
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1985A&AS...59...15A&db_key=AST