# Spectroscopy of Nine Cataclysmic Variable Stars

## TL;DR

This study provides optical spectroscopy and orbital period measurements for nine cataclysmic variable stars, revealing interesting properties such as secondary star detection, high space velocity, and magnetic accretion features, contributing valuable data to CV research.

## Contribution

The paper offers new orbital periods for nine CVs and detailed spectral analysis, including secondary star identification and magnetic accretion evidence, expanding the understanding of CV diversity.

## Key findings

- BF Eri has a K3 secondary star and likely belongs to the halo population.
- CZ Aql shows signs of magnetically-channeled accretion.
- V1006 Cyg's period falls within the 2-3 hour gap in CV distribution.

## Abstract

We present optical spectroscopy of nine cataclysmic binary stars, mostly dwarf novae, obtained primarily to determine orbital periods Porb. The stars and their periods are LX And, 0.1509743(5) d; CZ Aql, 0.2005(6) d; LU Cam, 0.1499686(4) d; GZ Cnc, 0.0881(4) d; V632 Cyg, 0.06377(8) d; V1006 Cyg, 0.09903(9) d; BF Eri, 0.2708804(4) d; BI Ori, 0.1915(5) d; and FO Per, for which Porb is either 0.1467(4) or 0.1719(5) d. Several of the stars proved to be especially interesting. In BF Eri, we detect the absorption spectrum of a secondary star of spectral type K3 +- 1 subclass, which leads to a distance estimate of approximately 1 kpc. However, BF Eri has a large proper motion (100 mas/yr), and we have a preliminary parallax measurement that confirms the large proper motion and yields only an upper limit for the parallax. BF Eri's space velocity is evidently large, and it appears to belong to the halo population. In CZ Aql, the emission lines have strong wings that move with large velocity amplitude, suggesting a magnetically-channeled accretion flow. The orbital period of V1006 Cyg places it squarely within the 2- to 3-hour "gap" in the distribution of cataclysmic binary orbital periods.