J/MNRAS/373/687 Spectra of 5 faint cataclysmic variables (Southworth+, 2006)
VLT/FORS spectroscopy of faint cataclysmic variables discovered
by the Sloan Digital Sky Survey.
Southworth J., Gansicke B.T., Marsh T.R., De Martino D., Hakala P.,
Littlefair S., Rodriguez-Gil P., Szkody P.
<Mon. Not. R. Astron. Soc., 373, 687-699 (2006)>
=2006MNRAS.373..687S 2006MNRAS.373..687S
ADC_Keywords: Binaries, eclipsing ; Binaries, cataclysmic ; Spectroscopy
Keywords: binaries: eclipsing - novae, cataclysmic variables
Abstract:
We present medium-resolution VLT/FORS2 spectroscopy of six cataclysmic
variables (CVs) discovered by the Sloan Digital Sky Survey (SDSS). We
determine orbital periods for SDSS J023322.61+005059.5
(96.08±0.09min), SDSS J091127.36+084140.7 (295.74±0.22min),
SDSS J103533.02+055158.3 (82.10±0.09min) and
SDSS J121607.03+052013.9 (most likely 98.82±0.16min, but the one-day
aliases at 92 and 107min are also possible) using radial velocities
measured from their Hα and Hβ emission lines. Three of the
four orbital periods measured here are close to the observed 75-80min
minimum period for CVs, indicating that the properties of the
population of these objects discovered by the SDSS are substantially
different to those of the CVs found by other means. Additional
photometry of SDSS J023322.61+005059.5 reveals a periodicity of
approximately 60min which we interpret as the spin period of the white
dwarf, suggesting that this system is an intermediate polar with a low
accretion rate. SDSS J103533.02+055158.3 has a period right at the
observed minimum value, a spectrum dominated by the cool white dwarf
primary star and exhibits deep eclipses, so is an excellent candidate
for an accurate determination of the parameters of the system. The
spectroscopic orbit of SDSS J121607.03+052013.9 has a velocity
amplitude of only 13.8±1.6km/s, implying that this system has an
extreme mass ratio. From several physical constraints we find that
this object must contain either a high-mass white dwarf or a
brown-dwarf-mass secondary component or both.
Description:
Time-resolved medium resolution spectroscopy is presented for six
cataclysmic variables discovered by the Sloan Digital Sky Survey. For
four of these systems the data are extensive enough to determine
orbital periods from measurements of the radial velocity motion of the
Balmer emission lines. For one of the systems we also present
time-resolved photometry which suggests that the object is an
intermediate polar.
Objects:
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RA (2000) DE Designation(s)
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02 33 22.6 +00 50 59 SDSS J023322.61+005059.5 = SDSS J023322.61+005059.5
09 11 27.4 +08 41 41 SDSS J091127.36+084140.7 = SDSS J091127.36+084140.8
09 32 38.2 +01 09 02 SDSS J093238.21+010902.5 = SDSS J093238.21+010902.5
10 10 37.0 +02 49 15 SDSS J101037.05+024914.9 = SDSS J101037.05+024915.0
10 35 33.0 +05 51 58 SDSS J103533.02+055158.3 = SDSS J103533.02+055158.4
12 16 07.0 +05 20 14 SDSS J121607.03+052013.9 = SDSS J121607.03+052013.9
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
spectra.dat 50 256 List of spectra available
int.dat 42 299 Isaac Newton Telescope photometry of
SDSS J023322.61+005059.5
lt.dat 42 193 Liverpool Telescope photometry of
SDSS J023322.61+005059.5
spectra/* . 254 Fits files of spectra
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Byte-by-byte Description of file: spectra.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- --- [SDSS]
6- 24 A19 --- SDSS Name of the source (JHHMMSS.ss+DDMMSS.s)
26- 30 F5.2 mag rmag SDSS r magnitude
32- 37 A6 --- Instr Instrument (ISIS-B, ISIS-R, FORS2) (1)
39- 50 A12 --- File Name of spectrum, in "spectra" subdirectory
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Note (1):
ISIS = Intermediate dispersion Spectrograph and Imaging System, on the
William Herschel Telescope (Blue and Red arms)
FORS2 = FOcal Reducer and low dispersion Spectrograph (VLT)
ph- = Photometry from Isaac Newton Telescope (INT) or
Liverpool Telescope (LT)
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Byte-by-byte Description of file: lt.dat int.dat
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Bytes Format Units Label Explanations
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1- 14 F14.6 JD JD Julian Date of midpoint of exposure
17- 24 F8.6 JD JDcor Heliocentric correction to Julian Date
29- 33 F5.3 mag dmag Differential magnitude of target
38- 42 F5.3 mag e_dmag Error on differential magnitude
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Acknowledgements:
John Southworth, jkt(at)astro.keele.ac.uk
(End) Patricia Vannier [CDS] 26-Mar-2007