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\IBVShead{4673}{25 February 1999}

\IBVStitletl{New dwarf novae on Moscow plates II}


\IBVSauth{S.V. ANTIPIN}
\IBVSinsto{Sternberg Astronomical Institute, 13, Universitetskij Prosp., Moscow 119899, Russia,
\newline e-mail: antip@sai.msu.su}

\IBVSabs{We report discovery and investigation of four new dwarf novae}

\SIMBADobj{Antipin V63, Antipin V64, Antipin V65 and Antipin V66}
\IBVStyp{ UG }
\IBVSkey{photometry}


\begintext

A search for new variable stars on Moscow archive plates was continued,
resulting in the discovery of four new UG-type stars
(Var\,63--66). The coordinates of new dwarf novae, taken from the
USNO A1.0 catalogue, are listed in Table 1 and their finding
charts are shown in Figure 1.

The stars were estimated by eye on plates taken with the 40-cm astrograph
in Crimea. The magnitudes of comparison stars are given in Table 2.
Standard sequences in NGC 1027 (Hoag et al., 1961) and in
IC 5146 (Walker, 1959) were used to obtain $B$-band magnitudes of
comparison stars for Var\,64 and Var\,66, respectively. Magnitudes of
comparison stars for Var\,63 and Var\,65 are based on the $B$-band
standard for 3C 454.3 (Angione, 1971) with the exception of
comparison stars {\it a, b, c} and {\it d} for Var\,63 whose $B$-band
magnitudes were measured photoelectrically by Shugarov (private communication)
at the 60-cm reflector in Crimea.

Var\,63, 64 and 65 are blue on the Palomar prints. The color
of Var\,66 is discussed below.

\smallskip


{\bf Var\,63 Peg.}
We estimated the star on 176 plates taken in JD\,2437176--48893.
The range of variability on our plates is 13\fmm 3--[17\fmm 7.
A total of seven outbursts have been revealed. The rather large
amplitude of variability --- more than $4\fmm 4B$ --- and long duration
of the best-observed outburst (\#6, see below) ---
more than 14 days --- allow us to consider Var\,63 as a UGSU-subtype
dwarf nova candidate. Further observations and search for superhumps
are strongly encouraged. Outbursts (JD24...):

\begin{center}
\begin{tabular}{ccrccrccr}
\#1 & 38949.461 & 13.43 & \#4 & 46081.234 & 13.29  & \#6 & 47390.407 & [17.7  \\
    &           &       &     &	   	  &	   &     & 47396.420 &  13.48 \\
\#2 & 44521.353 & 15.25 & \#5 & 47035.492 & [17.15 &     & 47397.440 &  13.34 \\
    & 44523.421 &[17.7  &     & 47041.485 &  16.45 &     & 47398.483 &  
13.38 \\
    &           &       &     & 47057.391 & [16.66 &     & 47407.368 &  15.61 \\
\#3 & 44901.347 & [17.7 &     & 	  &	   &     & 47410.457 &  17.70 \\
    & 44904.307 & 15.95 &     &	          &	   &     &	     &	      \\
    &           &       &     &	   	  &	   & \#7 & 48566.216 &  13.48 \\
\end{tabular}
\end{center}

\newpage

\IBVSfig{13cm}{4673-f1.eps}{Finding charts}

\IBVSfig{6.3cm}{4673-f2.ps}{Var66 Cyg. Summary light curves of the short-lasting
outburst (a) and the long-lasting~one~(b)}


\newpage
\begin{table}
\caption{Coordinates of New Variables}
\begin{center}
\begin{tabular}{cr@{\hr}c@{\mm}c@{\fsec}lr@{\deg}c@{\arcm}l}
\hline
Var & \multicolumn{4}{c}{$\alpha$ (J2000.0)} & \multicolumn{3}{c}{$\delta$ (J2000.0)} \\
\hline
Var 63 & 22 & 58 & 43 & 5 & +11 & 09 & 13\arcs \\
Var 64 & 03 & 21 & 14 & 4 & +61 & 05 & 26\arcs \\
Var 65 & 22 & 45 & 00 & 6 & +16 & 55 & 15\arcs \\
Var 66 & 21 & 44 & 03 & 7 & +44 & 39 & 02\arcs \\
\hline
\end{tabular}
\end{center}
\end{table}

\begin{table}
\caption{Comparison Stars}
\begin{center}
\begin{tabular}{cccccccccc}
\hline
Var & a & b & c & d & e & f & g & h & i \\
\hline
Var 63 & 12.63 & 13.57 & 14.12 & 14.39 & 15.83 & 16.66 & 17.15 & 17.4  & 17.7 \\
Var 64 & 13.74 & 14.18 & 14.71 & 15.07 & 15.59 & 16.07 & 16.69 & 16.94 & 17.6 \\
Var 65 & 15.53 & 16.22 & 16.80 & 17.4  & 17.6  \\
Var 66 & 15.02 & 15.65 & 16.73 & 17.2  & 17.5  \\
\hline
\end{tabular}
\end{center}
\end{table}


{\bf Var\,64 Cam.}
The UG-type variability was suspected on the basis of 223 estimates
(JD\,2433150--48627). The $B$-band magnitude changes in the range
14\fmm 0--[17\fmm 6. However, the star was in the bright state on two plates
only. Confirmation was needed for the classification.

This confirmation came from Pietz (1998) who found the outburst
on September 23, 1998. T. Kinnunen suspected short-term variations
close to the maximum of this outburst (Kato, 1998). This is very interesting
because our plate estimates show Var\,64 to be definitely variable
during the minimum of brightness (16\fmm 5--[17\fmm 6).

We measured the accurate position of Var\,64 on our plate
(in outburst, JD2442719) relative to 18 neighbouring GSC stars.
Our measurements yielded coordinates $3\hr 21\mm 14\fsec 33$,
$+61\deg 05\arcm 26\farcs 0$ (J2000), which are accurate to about
$\pm 0\farcs 3$. The variable is thus identical to the USNO A1.0
object at $3\hr 21\mm 14\fsec 41$, $+61\deg 05\arcm 25\farcs 7$ (J2000).

According to available data (Moscow estimates and {\it vsnet} observations),
all observed outbursts are short-lasting. Outbursts on Moscow plates (JD24...):

\begin{center}
\begin{tabular}{ccrccrccr}
\#1 & 42719.417 & 14.00 & \#2 & 48240.309 & [16.69   \\
    &           &       &     & 48244.363 &  14.40   \\
    &           &       &     & 48246.210 &  15.83   \\
\end{tabular}
\end{center}


{\bf Var\,65 Peg.}
We investigated this star on 153 plates (JD\,2444076--47477) and revealed
a total of seven outbursts. The range of variability on our plates
is 15\fmm 8--[17\fmm 6. Two best-observed outbursts are short
(\#1 and \#3, see below).
Outbursts (JD24...):

\begin{center}
\begin{tabular}{ccrrcrccr}
\#1& 44873.397 & [17.6  & \#3 & 45552.391 & [17.4  & \#6 & 46768.250 & [16.8  \\
   & 44875.366 &  15.81 &     & 45553.518 &  15.94 &     & 46769.174 &  16.08 \\
   & 44876.355 &  15.94 &     & 45558.381 &  17.45 \\
   & 44877.356 &  15.77 &     & 45562.487 & [17.6  & \#7 & 47410.457 &  16.01 \\
   & 44880.383 &  16.65 &     &           &        &     & 47417.364 &  17.04 \\
   & 44883.430 & [17.4  & \#4 & 45666.233 & [17.6  &     & 47421.440 & [17.4  \\
   &           &        &     & 45674.205 &  16.36 \\
\#2& 45199.526 &  16.15 \\
   & 45200.510 &  16.08 & \#5 & 46376.269 &  16.71 \\
   & 45205.469 & [17.4  &     & 46382.394 &  16.15 \\
\end{tabular}
\end{center}

\newpage
{\bf Var\,66 Cyg.}
We estimated this star on 208 plates taken in JD2433483--49634 and found
its $B$-band magnitude to vary from 15\fmm 25 to [17\fmm 5.
Moscow photographic observations show that the light curve of Var\,66 is
typical of dwarf novae. We observed two types of outbursts:
the long-lasting ones with 15\fmm 25$B$ at maximum and a duration of about
15 days and the short-lasting ones with 15\fmm 5$B$ at maximum and
a duration of about 6 days. We used three ``long'' best-observed outbursts
and five ``short'' ones to construct the summary light curves (Figure 2).
It is significant that the star spends little time in a
quiescent state with the outbursts following one after another
almost immediately.

The only problem is the color of the new variable.
The color index (blue minus red) is 1\fmm 3 in the USNO A1.0
and 0\fmm 7 in the USNO A2.0. It is not blue enough for a UG-type variable,
especially if compared to the colors of neighbouring stars. The issue
remains open and all observers are welcome to resolve the uncertainty.


\bigskip

The author would like to thank Drs.\ S.Yu.\ Shugarov, N.N. Samus and A.K. Dambis
for their help and attention to this investigation, and to express gratitude
to Mr.\ J. Manek for the software to visualize the USNO A1.0 and A2.0
catalogues. I acknowledge the very useful {\it vsnet} Data Base maintained by
Drs.\ D. Nogami, T. Kato, S. Masuda and H. Baba. This study was supported
in part by the Russian Foundation for Basic Research and the Council of
the Program for the Support of Leading Scientific Schools through
grants Nos.\,99-02-16333 and 96-15-96656.

\references

Angione, R.J., 1971, {\it AJ}, {\bf 76}, 412

Hoag, A.A., Johnson, H.L., Iriarte, B.,
Mitchell, R.I., Hallam, K.L., Sharpless, S., 1961, {\it Publ.\ of
the US Naval Obs.}, {\bf vol.\ XVII}, part VII, Washington

Kato, T., 1998, vsnet-alert {\bf 2232}

Pietz, J., 1998, vsnet-alert {\bf 2218}

(available on http://www.kusastro.kyoto-u.ac.jp/vsnet/Mail/vsnet-alert/msg02232.html,
 .../msg02218.html)

Walker, M.F., 1959, {\it ApJ}, {\bf 130}, 57

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