STUDIES OF EARLY-TYPE VARIABLE-STARS .9. THE ORBIT AND PHYSICAL PARAMETERS OF V1425-CYGNI

From a new spectroscopic orbit of the early-type binary system V1425 Cygni we find m(p) sin3 i=3.82 +/-0.07m., m(s) sin3 i=2.45+/-0.05m., (a(p)+a(s)) sin i=9.01 +/-0.07 R. and m(p)/m(s)=1.56+/-0.03. The velocity measures were determined iteratively by fitting each cross-correlation function with a digital profile generated from an observation at conjunction. These measures were then used as the basis for a tomographic reconstruction of the mean primary and secondary spectra. In turn digital masks generated from cross-correlation functions (ccf's) of these spectra yielded revised velocities and better orbits with systemic velocities in close accord. A spectrophotometric analysis indicates that the light ratio (p/s) is 1.72+/-0.15 which value in turn constrains the light-curve solution to that of a semi-detached system. V1425 Cygni had been thought to be a reverse Algol but our results rule conclusively against this interpretation. However the primary is well-evolved, occupying 92% of the inner Lagrangian lobe. Absolute dimensions have been determined for the system which is reddened [E(B-V)=0.16m+/-0.01m] at a distance of 510+/-35 pc.