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\IBVShead{4792}{4 November 1999}

\IBVStitle{Possible Identification of M\lowercase{is}V0106 and NSV 25425}

\IBVSauth{Seiichi Yoshida$^1$, KenIchi Kadota$^2$, Taichi Kato$^3$}

\IBVSinst{MISAO Project, 1065-16 Miyawada Fujishiro-machi Kitasoma-gun Ibaraki 300-1514, Japan,\\ \indent e-mail: seiichi@muraoka.info.waseda.ac.jp}

\IBVSinst{MISAO Project, 77-1-3-12-204 Koshikiya Ageo City Saitama 362-0064, Japan,\\ \indent e-mail: kenic-k@astroarts.co.jp}

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

\IBVSabs{This report discusses on the possible identification of MisV0106 and}
\IBVSabs{NSV 25425 based on the MISAO Project observations.}

\SIMBADobj{NSV 25425}

\begintext

This report discusses the possible identification of MisV0106, one of 
new variable stars discovered in the course of the MISAO Project, and 
NSV 25425, one of the suspected variable stars in the NSV catalog (New
Catalogue of Suspected Variable Stars) Supplement 1.0 (Kazarovets et
al.\ 1998).

In the course of variable star survey based on the MISAO Project observations, the variable brightness of USNO-A2.0 1200.16773850,
${\rm R.A.}\!=\!21\hr 00\mm 37\fsec 223, {\rm Decl.}\!=\!+37\deg 28\arcm 55\farcs 08$ (2000.0), 14.5 mag$(R)$, 17.8 mag$(B)$, was discovered and named as MisV0106 (Yoshida et al.\ 1999).

NSV 25425 is 52 arcsec from MisV0106. At the position of NSV 25425, there is a star USNO-A2.0 1200.16771307, ${\rm R.A.}= 21\hr 00\mm 34\fsec 472$, ${\rm Decl.}= +37\deg 29\arcm 36\farcs 80$ (2000.0), 13.9 mag$(R)$, 15.4 mag$(B)$ (see Figure~1).

Table 1 shows the photometry of these two stars, obtained automatically
by the PIXY system from unfiltered CCD images taken by Kadota between
1999 May and September. The magnitudes were measured using the USNO-A1.0 catalog based on a preliminary $V$ magnitude calculated from $R$ and $B$ magnitude in the catalog based on Kato's (1998) equation:
\[
V = R + 0.375 (B - R)
\]
Further details are the same as described in Yoshida and Kadota (1999).
These observations confirmed the variability of USNO-A2.0 1200.16773850,
while USNO-A2.0 1200.\hskip0pt{}16771307 was constant within the error.

In order to confirm the color of the two stars, we measured relative
colors of these stars by comparing images with an R60-filter and an
IR-blocking filter (Table 2). Red stars are relatively fainter through an IR-blocking filter. The data in the USNO-A2.0 catalog of these two stars implies both stars are red. Our observations confirm that USNO-A2.0 1200.16773850 is evidently red, while USNO-A2.0 1200.16771307 is not red.

The finding chart of NSV 25425 is given in Margoni and Stagni (1984).
The star labelled as NSV 25425 on the chart is identical with USNO-A2.0
1200.16771307. However, there is a remark on NSV 25425 that ``{\it is very bright in the infrared}''. This does not agree with the result of our observations.

As a conclusion, the identification of NSV 25425 with USNO-A2.0 1200.16771307 is possibly a mistake and USNO-A2.0 1200.16773850 (MisV0106) is the true NSV 25425.

Because the finding chart of Margoni and Stagni (1984) was based on a blue photographic plate, USNO-A2.0 1200.16773850, a red star, was too faint to be visible on the chart. This may explain why Margoni and Stagni (1984) labelled the wrong star as the variable.

\IBVSfig{7cm}{4792-f1.ps}{A: USNO-A2.0 1200.16773850 (MisV0106)\\ B: USNO-A2.0 1200.16771307}

\begin{table}
\begin{center}
\caption{Photometry (unfiltered CCD)}
\begin{tabular}{ccc} \hline
JD & USNO-A2.0 1200.16773850 & USNO-A2.0 1200.16771307 \\ \hline
2451300.25 & 12.7 & 15.3 \\
2451367.20 & 14.0 & 15.4 \\
2451408.22 & 14.4 & 15.4 \\
2451426.12 & 13.4 & 15.2 \\
\hline
\end{tabular}

\caption{Photometry (filtered CCD)}
\begin{tabular}{ccc} \hline
Filter & USNO-A2.0 1200.16773850 & USNO-A2.0 1200.16771307 \\ \hline
none & 13.4 & 15.2 \\
R60 & 13.2 & 15.1 \\
IR-blocking & 15.6 & 15.3 \\
\hline
\end{tabular}
\end{center}
\end{table}

\references

Kato, T., 1998, \\ {\tt http://www.kusastro.kyoto-u.ac.jp/vsnet/Mail/vsnet-chat/msg00700.html}

Kazarovets, E. V., Samus, N. N., Durlevich, O. V., 1998, {\it IBVS}, No. 4655

Margoni, R., Stagni, R., 1984, {\it AsAp Suppl.}, 56, 87

Yoshida, S., Kadota, K., 1999, {\it IBVS}, No. 4746

Yoshida, S., Kadota, K., Kato, T., 1999, {\it IBVS}, No. 4770

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