Spectroscopic Orbital Periods for 29 Cataclysmic Variables from the Sloan Digital Sky Survey

Abstract

We report follow-up spectroscopy of 29 cataclysmic variables from the Sloan Digital Sky Survey (SDSS), 22 of which were discovered by SDSS and seven other previously known systems that were recovered in SDSS. The periods for 16 of these objects were included in the tabulation by Gaensicke et al. (2009). While most of the systems have periods less than 2 hours, only one has a period in the 80-86 minute 'spike' found by Gaensicke et al. (2009), and 11 have periods longer than 3 hours, indicating that the present sample is skewed toward longer-period, higher-luminosity objects. Seven of the objects have spectra resembling dwarf novae, but have apparently never been observed in outburst, suggesting that many cataclysmics with relatively low variability amplitude remain to be discovered. Some of the objects are notable. SDSS J07568+0858 and SDSS J08129+1911 were previously known to have deep eclipses; in addition to spectroscopy, we use archival data from the CRTTS to refine their periods. We give a parallax-based distance of 195 (+54, -39) pc for LV Cnc (SDSS J09197+0857), which at Porb = 81 m has the shortest orbital period in our sample. SDSS J08091+3814 shows both the spectroscopic phase offset and phase-dependent absorption found in SW Sextantis stars. The average spectra of SDSS J08055+0720 and SDSS J16191+1351 show contributions from K-type secondaries, and SDSS J080440+0239 shows a contribution from an early M star. We use these to constrain the distances. SDSS J09459+2922 has characteristics typical of a magnetic system. SDSS11324+6249 may be a novalike variable, and if so, its orbital period (99 min) is unusually short for that subclass.

Accepted for Astronomical Journal. 43 pages, 10 figures

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Cited by in corpus (10)

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• The evolutionary status of Cataclysmic Variables: Eclipse modelling of 15 systems
• Evidence for reduced magnetic braking in polars from binary population models
• A catalogue of cataclysmic variables from 20 years of the Sloan Digital Sky Survey with new classifications, periods, trends and oddities
• Survey of Period Variations of Superhumps in SU UMa-Type Dwarf Novae. IX: The Ninth Year (2016-2017)
• TESS light curves of cataclysmic variables -- III -- More superhump systems among old novae and novalike variables
• Spectroscopic properties of the dwarf nova-type cataclysmic variables observed by LAMOST
• New evidence for the precession of tilted disk in SDSS J081256.85+191157.8
• Spectroscopic Studies of 30 Short-period Cataclysmic Variable Stars, and Remarks on the Evolution and Population of Similar Objects
• Investigation of superhumps in SU UMa-type dwarf novae based on the observations of TESS