Radial-velocity measurements and sine-curve fits to the orbital radial velocity variations are presented for ten close binary systems: DU Boo, ET Boo, TX Cnc, V1073 Cyg, HL Dra, AK Her, VW LMi, V566 Oph, TV UMi and AG Vir. By this contribution, the DDO program has reached the point of 100 published radial velocity orbits. The radial velocities have been determined using an improved fitting technique which uses rotational profiles to approximate individual peaks in broadening functions.Three systems, ET Boo, VW LMi and TV UMi, were found to be quadruple while AG Vir appears to be a spectroscopic triple. ET Boo, a member of a close visual binary with P vis = 113 years, was previously known to be a multiple system, but we show that the second component is actually a close, non-eclipsing binary. The new observations enabled us to determine the spectroscopic orbits of the companion, non-eclipsing pairs in ET Boo and VW LMi. The particularly interesting case is VW LMi, where the period of the mutual revolution of the two spectroscopic binaries is only 355 days.While most of the studied eclipsing pairs are contact binaries, ET Boo is composed of two double-lined detached binaries and HL Dra is single-lined detached or semi-detached system. Five systems of this group were observed spectroscopically before: TX Cnc, V1073 Cyg, AK Her (as a single-lined binary), V566 Oph, AG Vir, but our new data are of much higher quality than the previous studies.

Radial-velocity measurements and sine-curve fits to the orbital velocity variations are presented for the seventh set of ten close binary systems: V410 Aur, V523 Cas, QW Gem, V921 Her, V2357 Oph, V1130 Tau, HN UMa, HX UMa, HD 93917, NSV 223. All systems, but three (V523 Cas, HD 93917, NSV 223), were discovered photometrically by the Hipparcos mission. All systems are double-lined (SB2) binaries and all, but the detached, very close system V1130 Tau, are contact binaries. The broadeningfunction permitted improvement of the orbital elements for V523 Cas, which was the only system observed before for radial velocity variations. Spectroscopic/visual companions were detected for V410 Aur and HX UMa. Several of the studied systems are prime candidates for combined light and radial-velocity synthesis solutions.

We present results from Hubble Space Telescope ultraviolet spectroscopy of the massive X-ray and black hole binary system, HD 226868 = Cyg X-1. The spectra were obtained at both orbital conjunction phases in 2002 and 2003, when the system was in the X-ray high /soft state. The UV stellar wind lines suffer large reductions in absorption strength when the black hole is in the foreground due to the X-ray ionization of the wind ions. We constructed model UV wind line profiles assuming that X-ray ionization occurs everywhere in the wind except the zone where the supergiant blocks the X-ray flux. The good match between the observed and model profiles indicates that the wind ionization extends to near the hemisphere of the supergiant facing the X-ray source. We also present contemporaneous spectroscopy of the H emission that forms in the high-density gas at the base of the supergiant's wind and the He ii k4686 emission that originates in the dense, focused wind gas between the stars. The H emission strength is generally lower in the high/soft state than in the low/ hard state, but the He ii k4686 emission is relatively constant between X-ray states. The results suggest that mass transfer in Cyg X-1 is dominated by the focused wind flow that peaks along the axis joining the stars, and that the stellar wind contribution from the remainder of the hemisphere facing the X-ray source is shut down by X-ray photoionization effects (in both X-ray states).

Radial-velocity measurements and sine-curve fits to the orbital radial velocity variations are presented for the last eight close binary systems analyzed the same way as in the previous papers of this series: QX And, DY Cet, MR Del, HI Dra, DD Mon, V868 Mon, ER Ori, and Y Sex. For another seven systems (TT Cet, AA Cet, CW Lyn, V563 Lyr, CW Sge, LV Vir and MW Vir) phase coverage is insufficient to provide reliable orbits but radial velocities of individual components were measured. Observations of a few complicated systems observed throughout the DDO close-binary program are also presented; among them an especially interesting is the multiple system V857 Her which -in addition to the contact binary -very probably contains one or more subdwarf components of much earlier spectral type. All suspected binaries which were found to be most probably pulsating stars are briefly discussed in terms of mean radial velocities and projected rotation velocities (v sin i) as well as spectral type estimates. In

Radial-velocity measurements and sine-curve fits to the orbital velocity variations are presented for the sixth set of ten close binary systems: SV Cam, EE Cet, KR Com, V410 Cyg, GM Dra, V972 Her, ET Leo, FS Leo, V2388 Oph, II UMa. All systems except FS Leo are double-lined spectroscopic binaries. The type of FS Leo is unknown while SV Cam is a close, detached binary; all remaining systems are contact binaries. Eight binaries (all except SV Cam and V401 Cyg) are the recent photometric discoveries of the Hipparcos satellite project. Five systems, EE Cet, KR Com, V401 Cyg, V2388 Oph, II UMa, are members of visual/spectroscopic triple systems. We were able to observe EE Cet separate from its companion, but in the remaining four triple systems we could separate the spectral components only through the use of the broadening-function approach. Several of the studied systems are prime candidates for combined light and radial-velocity synthesis solutions.RS CVn-type system.Our double-lined (SB2) spectroscopic orbit is very well defined, with small errors of the orbital parameters. We note that determinations of the radial velocity semi-amplitude of the primary component, K 1 , agree well in the four existing solutions. Starting with Hiltner (1953) (as reanalyzed by Rainger et al. (1991)), Rainger et al. (1991), Pojmanski (1998) and the current, the results have been (in km s −1 ) : 121.7 ± 1.9, 122.3 ± 1.5, 118.5 ± 2.0, and 121.86 ± 0.76. The results of Pojmanski (1998) differ the most, but are still within the errors of the solutions. The center of mass velocity, V 0 , seems to show a secular progression, although the data of Pojmanski (1998) deviate from the trend. In the same order as before: −16.2 ± 1.4, −11.2 ± 1.2, −13.7 ± 1.5 and −9.13 ± 0.78 km s −1 . Noting that the observations were made in 1947, 1988, 1993 and 1997, the trend may be related to the motion about the third body with the period of about 65 -75 years and the semi-amplitude of about 2 km s −1 (Rainger et al. 1991).The results of Pojmanski (1998), although the first to reveal the motion of the secondary component, show deviations described above and, even more importantly, differ rather substantially from our results in the value of K 2 : 211.5 ± 5.5 versus our 190.17 ± 1.73 km s −1 . Possibly, the discrepancies are due to the rather complex reduction scheme of the previous study which involved successive removal of the two spectral signatures from individual spectra. This was entirely unnecessary in our case because the broadening functions that we analyzed were very well defined and radial velocities of both components could be measured with great ease. Figure 4 shows one of the broadening functions for SV Cam, in comparison with other systems analyzed in this paper. On the basis of the widths of the individual signatures in the broadening functions, and taking into consideration the instrumental broadening, we estimate the apparent rotation velocity of the components, V 1 sin i = 122 ± 10 km s −1 and V 2 sin i = 85 ± 8 km s −1 . Patkos & Hempelman...