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\IBVShead{4553}{6 February 1998}

\IBVStitle{On the recent Nova in NGC\,205}


\IBVSauth{A.S. SHAROV$^1$, A. ALKSNIS$^2$}
\IBVSinst{Sternberg Astronomical Institute, 13, Universitetskij Prosp., Moscow 119899, Russia
[sharov@sai.msu.su]} %email

\IBVSinst{Institute of Astronomy, University of Latvia, Raina Boulevard 19, Riga, LV-1586, Latvia
[aalksnis@acad.latnet.lv]} %email


\IBVSabs{We present brightness estimates for the Nova}
\IBVSabs{recently discovered in NGC 205.}

\IBVSobj{N1997-in-NGC205}
\IBVStyp{ N }
\IBVSkey{photometry}


\begintext

  Qiao et al. (1997) reported the discovery of a nova in NGC 205
  in the course of the Beijing Astronomical Observatory supernova
  survey. They derived unfiltered CCD magnitudes of the nova on three
  nights in succession, and on one of the nights obtained a
  low-resolution spectrogram which showed features typical of novae
  after maximum.

  We  estimated the brightness  of the Nova  on  plates taken for
search of novae in M~31  with the Baldone 80-cm Schmidt telescope
of the Institute of Astronomy, University of Latvia, and with the
50-cm Maksutov telescope at  the Crimean Laboratory of the Sternberg
Astronomical  Institute of the  Moscow  University.

  The dates, times of the middle of exposure in Julian days, and
  B-magnitudes of the Nova  based  on the photometric sequences in the
central region of M 31 (Rosino et al., 1989) are given in  Table 1.
\vskip 3mm
\centerline{Table 1}
\vskip 2mm
\begin{center}
\begin{tabular}{lcl}
\hline
\noalign{\medskip}
Date,&JD 2450000+ &$B$\\
1997\\
\noalign{\medskip}
\hline
\noalign{\medskip}
                 Nov 5/6   &   758.300&   (19.    \\
                 Nov 5/6   &   758.340&   (19.9   \\
                 Nov 9/10  &   762.482&   (19.5   \\
                 Nov 20/21 &   773.242&    17.8   \\
                 Nov 20/21 &   773.319&    18.0   \\
                 Nov 24/25 &   777.217&    18.5   \\
                 Nov 28/29 &   781.194&    19.0:: \\
                 Dec 1/2   &   784.406&    19.3:: \\
                 Dec 5/6   &   788.377&    19.3:  \\
                 Dec 5/6   &   788.464&   (19     \\
                 Dec 16/17 &   799.187&   (19.5   \\
                 Dec 19/20 &   802.191&   (19.9   \\
                 Dec 19/20 &   802.227&    20.1   \\
\noalign{\medskip}
\hline
\end{tabular}
\end{center}

\bigskip

  From the nearly simultaneous  (Nov. 23.4 and Nov. 23.44 UT)
$V= 18.1$  and unfiltered $m({\rm CCD}) = 18.5$  magnitudes  (Qiao et al.,
1997) and the average intrinsic colour index  $B - V = 0.23$  for
novae  at maximum light  (van den Bergh and Younger, 1987)  we
derive  $B - m({\rm CCD}) = - 0.17$,  and from magnitudes  by Qiao et al.
we obtain
estimates of  $B$-magnitudes of the Nova: 18.6  at JD 2450774.04,
18.2  at 0775.00,  and 18.3 at 0775.92, values that on the average
fit well to our light curve.

  The available  photometric data  for the Nova  do not allow to
determine time and value  of the maximum  brightness exactly. However,
the Nova  was at least as bright as $B = 17.8$,
and probably  17.4  or even brighter (see Figure 1). In the case of the mentioned
alternatives, the estimated  rate of decline is  $\log (100d) = 0.94$
and $\log(100d) = 1.03$,  which corresponds to the fast novae according
to the classification by Payne-Gaposchkin (1957).

\IBVSfig{10cm}{4553-f1.ps}{The light curve of the nova in NGC 205. Filled circles: our confident
measurements; open circles: our uncertain measurements; triangles:
our bright limits; crosses: measurements by Qiao et al. reduced to
$B$ magnitudes by us.}

  It  is  difficult to prove  that  this Nova  really  belongs to
NGC 205.  If we suppose  that  the Nova  is located  in  the main
plane of the galaxy  M 31,  then the Nova's distance from its center  is
about 31 kpc,  as large as  that  of another  very  distant  Nova
ShA 39 in  M 31 (Sharov and Alksnis, 1995).

According to measurements by Yu.A. Shokin, the coordinates of the Nova
are the following:

$$\alpha_{1950.0} =  0\hr 37\mm 39\fsec 478$$
$$\delta_{1950.0} = +41\deg 27\arcm 00\farcs 05$$

  The  Nova  is the second  known nova  in the region  of NGC 205.
The first one was discovered by Zwicky (1957)  $7'$ north from  the
center of NGC 205  on September 21, 1955. However, no details were
published.

  We wish to thank  Yu.A. Shokin  for determining  the coordinates
of the Nova. One of the authors (A.Sh.) is  also grateful to the
Russian Foundation for Basic Research  and  to the Council of the
Program for the Support  of  Leading  Scientific  Schools
(grants 95-02-03942  and  96-15-96656).

\vskip 1cm

\references

Payne-Gaposchkin, C., 1957, {\it The Galactic Novae}, North-Holland  Publ.
Comp., Amsterdam, p.24

Qiao, Q.Y., Qiu, Y.L., Hu, J.Y., Li, W.D., Esamdin, A., Zhang, Y.,
1997, {\it IAU Circ.}, No.\,6777

Rosino, L., Capaccioli, M., D'Onofrio, M., Della Valle, M., 1989,
{\it Astron. J.}, {\bf 97}, 83

Sharov, A.S., Alksnis, A., 1995, {\it Pis'ma v Astron. Zh.}, {\bf 21}, 650  =
{\it Astron. Lett.}, {\bf 21}, 579

van den Bergh, S., Younger, P.F., 1987, {\it A\&A Suppl. Ser.}, {\bf 70}, 125

Zwicky, F., 1957, {\it Morphological Astronomy}, Berlin--G\"ottingen--Heidelberg, p.210

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