[vsnet-outburst 11845] V496 Aur outburst

[Taichi Kato]

V496 Aur outburst

   CRTS detected an outburst of V496 Aur, yet unclassified dwarf nova.

CSS101127:072752+404652 http://nesssi.cacr.caltech.edu/catalina/20101127/1011271400314126132.html 07 27 52.23 +40 46 52.5 15.72 http://cas.sdss.org/dr7/en/tools/chart/navi.asp?ra=111.9676300&dec=40.7812400 CV

   The following IBVS-type report might be helpful.  The CRTS data indicate
relatively regular outburst amplitudes.

===

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\begin{document}

\IBVShead{xxxx}{xx September 1999}

\IBVStitletl{CCD OBSERVATION OF THE NEW CATACLYSMIC VARIABLE IN AUR}

\IBVSauth{T.~Kato$^1$}
\vskip 5mm

\IBVSinst{Dept. of Astronomy, Kyoto University, Kyoto 606-8502, Japan,
          e-mail: tkato,katsura at kusastro.kyoto-u.ac.jp}

\IBVSobj{New CV in Aur}
\IBVStyp{UG}
\IBVSkey{Dwarf novae -- photometry}

\begintext

   Qiu et al. (1997) reported the discovery of a new cataclysmic variable
in Aur, located at 07\h 27\m 52\fs 20, +40\deg 46\arcm 55\farcs 5 (J2000.0).
Qiu et al. (1997) reported the maximum unfiltered CCD magnitude of 15.7,
and the absence of the quiescent counterpart on the POSS plates.  From
spectroscopy in outburst, they confirmed the dwarf nova classification
of the object.

   Wei et al. (1998) reported another outburst of this new cataclysmic
variable.  Since Wei et al. (1998) indicated the outburst already lasted
at least five days, we undertook time-resolved CCD photometry to test
the presence of short-term modulations, especially superhumps.

   The observation was done on 1998 December 18 using an unfiltered ST-7
camera attached to the Meade 25-cm Schmidt-Cassegrain telescope.
The exposure time was 30 s.  The images were dark-subtracted,
flat-fielded, and analyzed using the Java$^{\rm TM}$-based PSF photometry
package developed by the author.  The flux of the variable was
measured relative to GSC 2961.289 (USNO $r$-magnitude 11.8), whose constancy
was confirmed by comparison with GSC 2961.38 (USNO $r$-magnitude 11.8).
The fluxes given below are expressed relative to GSC 2961.289.

\IBVSfig{10cm}{fig1.ps}{Light curve of new CV in Aur}

   Figure 1 illustrates the light curve of the present observation.
Because of the faintness of the object, 18 to 50 successive frames were
averaged to represent points in Figure 1.  The mean flux corresponds
to an unfiltered magnitude of 17.4, based on the USNO $r$-magnitude.
We were not able to detect large-amplitude short-term variation.
The differences between observed points were within the errors of
measurements.  The safe upper limit of superhump modulation was thus
0.2 mag.

\newpage
\begin{table}
\begin{center}
Table 1. The 1998 December outburst of the new CV in Aur \\
\vspace{10pt}
\begin{tabular}{ccc}
\hline
JD       & unfiltered CCD mag & source \\
\hline
2451157.23 & 16.6 & Wei et al. (1998) \\
2451160.23 & 16.0 & Wei et al. (1998) \\
2451162.28 & 16.6 & Wei et al. (1998) \\
2451166.05 & 17.4 & this paper \\
\hline
\end{tabular}
\end{center}
\end{table}

   Table 1 summarizes the overall course of the 1998 December outburst.
The relatively rapid decline for a superoutburst of SU UMa stars, and
the apparent lack of large-amplitude light modulation seem to support
the SS Cyg-type classification of this object.  An earlier notification
on the next outburst, and prompt follow-up time-resolved photometry
at the brightest epoch will be needed to unambiguously determine the
dwarf nova subtype.

\vskip 3mm

   This work is partly supported by the Grant-in-Aid for Scientific Research
(10740095) of the Japanese Ministry of Education, Science, Culture.

\begin{references}

Qiu, Y.-L., Qiao, Q.-Y., Li, W.-D., Hu, J.-Y., 1997, {\it IAUC}, No. 6758

Wei, J.-Y., Qiu, Y.-L., Qiao, Q.-Y., Hu, J.-Y., 1998, {\it IAUC}, No. 7068

\end{references}

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