Return to HomePageTonny Vanmunster wrote in [vsnet-chat 208]:
>>Selected CCD results: >>0000+00 DW CNC 2450523.3243 1997-03-15 0.8243 14.4, is >>this an outburst ? > >It probably is. The star is catalogued as an UG cataclysmic variable with >a magnitude range of 15v - 17.5v. Past outburst observations list maximum >magnitudes around mag 14.5 (CCD unfiltered). Recurrence time of this >poorly studied object seems to be rather short, although I have not been >able to derive an exact value. Maybe Taichi Kato has more information on >DW Cnc (discovery paper, ...) ?
DW Cnc (=SVS 2424) was discovered by J. A. Stepanian (Perem. Zvezdy 21, 691, 1982) in the course of a search for UV-bright galaxies at Byurakan. The follow-up spectroscopic study revealed the presence of doubly peaked emission lines of hydrogen, HeI, HeII and CaII. Photometrically, following estimates were listed.
2440920 17.5
41003 17
42804 15
43222 16.5
43607 16
43608 15.5
43637 17.5
43952 16.5
43956 16
43961 15.5
43963 15
The star was then studied by I. M. Kopylov et al. (Astrophysics 28, 168, 1988). In the description of DW Cnc = FBS 0756+164 they wrote: "The lines of the hydrogen series are moderately broad. The Balmer decrement is very gentle. The line He II 4686 is rather weak, about twice as weak as He I 4471 and about ten times weaker then H beta. The line Ca II (K) is observed in emission. Numerous weak shell lines of low excitation (Fe II et al.) are observed. The object may be classified as adwarf nova."
Makoto Iida (VSOLJ) once communicated that he suspected this star to be a Z Cam star based on his CCD measurements.
This article by I. M. Kopylov et al. is interesting in that this FBS survey includes both famous and neglected CVs. Examples:
(1950.0) mag their classification present
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FBS 0022-021 002224 -0210 15 dwarf nova
FBS 0107-082 010706 -0814 15 novalike
FBS 0756+164 075606 +1625 15-17.5 dwarf nova
FBS 0948+343 094842 +3421 14-17 A5-A7V = RZ LMi, peculiar DN
FBS 1031+590 103100 +5903 14.5-15 polar = DW UMa, NLAD+E
FBS 2320+181 232036 +0108 13-18.5 dwarf nova, IP Peg
FBS 2351+228 235118 +2252 15-16 recurrent nova? (*1)
(*1) FBS 2351+228 shows both TiO bands (M-type spectrum) and H alpha in emission. The authors state the spectrum resembles T CrB and RS Oph at minimum.
Regards,
Taichi Kato
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