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 of which are previously known systems that were recovered in SDSS. The periods for 16 of these objects were included in the tabulation by Gänsicke et al. While most of the systems have periods less than 2 hr, only one has a period in the 80-86 minutes "spike" found by Gänsicke et al., and 11 have periods longer than 3 hr, 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 Catalina Real Time Transient Survey to refine their periods. We give a parallax-based distance of 195 (+54, −39) pc for LV Cnc (SDSS J09197+0857), which at P orb = 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 minutes) is unusually short for that subclass.

Hard X-ray cataclysmic variables

“…Both BAT and IBIS-ISGRI catalogues, still carry tentative new CV identifications, with many sources claimed as magnetic, based on optical follow-ups (e.g. Masetti et al, 2012Masetti et al, , 2013Parisi et al, 2014;Thorstensen & Halpern, 2013;Thorstensen et al, 2015) and thus subject of revisions ( Fig. 1).…”

V1460 Her: a fast spinning white dwarf accreting from an evolved donor star

“…Whereas the physical properties of both stellar components of these "failed SN Ia" can be accurately measured, providing a powerful diagnostic of this evolutionary pathway, only a relatively small number of such systems have so far been identified (e.g. Rodríguez-Gil et al 2009;Thorstensen 2015;Thorstensen et al 2015;Yu et al 2019;Rebassa-Mansergas et al 2014). Here we report that the system V1460 Her is the newest member of this exclusive list of CVs.…”

Spectroscopic properties of the dwarf nova-type cataclysmic variables observed by LAMOST

“…The spectral feature of the M star donor can be seen in several objects which have been reported to contain the M type stars previously (except for V367 Peg). These objects are GY Cnc (Gänsicke et al 2000), IP Peg (Martin et al 1987), HH Cnc (Thorstensen et al 2015), SDSS J100658.41+233724.4 (Southworth et al 2009), SDSS J105550.08+095620.4 (Thorstensen & Skinner 2012), U Gem (Stauffer et al1979), V405 Peg (Thorstensen et al2009), V1239 Her (Littlefair et al2006) and VZ Sex (Mennickent et al2002). Also, there is a weak absorption feature around λ8180 that can be found in some of such objects.…”