Christopher S. Peters

Spectroscopy of Four Cataclysmic Variables with Periods above 7 Hours

We present spectroscopy of four cataclysmic variables. Using radial velocity measurements, we find orbital periods Porb for the first time: for GY Hya, 0.347230(9) days, for SDSS J204448045929, 1.68(1) days, for V392 Hya, 0.324952(5) days, and for RX J1951.73716, 0.492(1) days. We also detect the spectra of the secondary stars, estimate their spectral types, and derive distances based on surface brightness and Roche lobe constraints.

Optical Studies of 20 Longer-Period Cataclysmic Binaries*

We obtained time-series radial-velocity spectroscopy of 20 cataclysmic variable stars, with the aim of determining orbital periods Porb. All of the stars reported here prove to have Porb > 3:5 h. For 16 of the stars, these are the first available period determinations, and for the remaining four (V709 Cas, AF Cam, V1062 Tau, and RX J2133 þ 51), we use new observations to improve the accuracy of previously published periods. Most of the targets are dwarf novae, without notable idiosyncrasies. Of the remainder, three (V709 Cas, V1062 Tau, and RX J2133 þ 51) are intermediate polars (DQ Her stars); one (IPHAS 0345) is a secondary-dominated system without known outbursts, similar to LY UMa; one (V1059 Sgr) is an old nova; and two others (V478 Her and V1082 Sgr) are long-period novalike variables. The stars with new periods are IPHAS 0345 (0.314 days); V344 Ori (0.234 days); VZ Sex (0.149 days); NSVS 1057 þ 09 (0.376 days); V478 Her (0.629 days); V1059 Sgr (0.286 days); V1082 Sgr (0.868 days); FO Aql (0.217 days); V587 Lyr (0.275 days); V792 Cyg (0.297 days); V795 Cyg (0.181 days); V811 Cyg (0.157 days); V542 Cyg (0.182 days); PQ Aql (0.247 days); V516 Cyg (0.171 days); and VZ Aqr (0.161 days). Noteworthy results on individual stars are as follows. We see no indication of the underlying white dwarf star in V709 Cas, as has been previously claimed; based on the nondetection of the secondary star, we argue that the system is farther away that had been thought and the white dwarf contribution is probably negligible. V478 Her had been classified as an SU UMa-type dwarf nova, but this is incompatible with the long orbital period we find. We report the first secondary-star velocity curve for V1062 Tau. In V542 Cyg, we find a late-type contribution that remains sta- tionary in radial velocity, yet the system is unresolved in a direct image, suggesting that it is a hierarchical triple system.

Spectroscopy of Five Old Novae: New or Refined Orbital Periods*

We present spectroscopy of five old novae and report new or refined orbital periods, Porb. For two of the systems, we detect a spectral contribution from the secondary star and infer distances from spectroscopic parallax. Updated period histograms of old novae and all other cataclysmic variables (CVs) are included. Statistical tests show that the orbital period distribution of old novae is significantly different from that of other CVs.

A NEW, BRIGHT, SHORT-PERIOD, EMISSION LINE BINARY IN OPHIUCHUS*

The 11th magnitude star LS IV-08°3 has been classified previously as an OB star in the Luminous Stars survey, or alternatively as a hot subdwarf. It is actually a binary star. We present spectroscopy, spectroscopic orbital elements, and time-series photometry from observations made at the Kitt Peak National Observatory 2.1 m, Steward Observatory 2.3 m, MDM Observatory 1.3 m and 2.4 m, Hobby-Eberly 9.2 m, and Michigan State University 0.6 m telescopes. The star exhibits emission of varying strength in the cores of H and He I absorption lines. Emission is also present at 4686 A (He II) and near 4640/4650 A (N III/C III). Time-series spectroscopy collected from 2005 July to 2007 June shows coherent, periodic radial velocity variations of the Hα line, which we interpret as orbital motion with a period of 0.1952894(10) days. High-resolution spectra show that there are two emission components, one broad and one narrow, moving in antiphase, as might arise from an accretion disk and the irradiated face of the mass donor star. Less coherent, low-amplitude photometric variability is also present on a timescale similar to the orbital period. Diffuse interstellar bands indicate considerable reddening, which however is consistent with a distance of ~100-200 pc. The star is the likely counterpart of a weak ROSAT X-ray source, whose properties are consistent with accretion in a cataclysmic variable (CV) binary system. We classify LS IV-08°3 as a new member of the UX UMa subclass of CV stars.