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\IBVShead{4725}{11 June 1999}

\IBVStitletl{PHOTOELECTRIC VI{\Large $_c$} OBSERVATIONS AND NEW CLASSIFICATION}{ FOR RV NORMAE}

\IBVSauth{L. N. Berdnikov$^1$, D. G. Turner$^2$}
\IBVSinst{Sternberg Astronomical Institute, 13 Universitetskij prosp.,
 Moscow 119899, Russia\\ e-mail: berdnik@sai.msu.su}
\IBVSinst{Saint Mary's University, Halifax, Nova Scotia,
 B3H 3C3, Canada}

\SIMBADobj{RV Nor}

\begintext

\IBVSTnam{RV Nor = GSC 8714.0914}

\IBVSTcoo{16\hr04\mm10\sec}{$-56\deg$04\arcm48\arcs}{2000}

\IBVSTobs{South African Astronomical Observatory, 0.5-m reflector}

\IBVSTdet{Photomultiplier Hamamatsu}

\IBVSTfil{$VI_c$}

\IBVSTcomp{No. We conducted the ``all sky photometry''}

\IBVSTchk{No. See above}

\IBVSTsys{$VI_c$}{Standard stars from E-regions}

\IBVSTdata{Through IBVS Web-site as 4725-t1.txt}

\IBVSTtyp{ RV }

\IBVSTrem{
RV Nor is listed in the GCVS-IV as a type II Cepheid with the elements:
$$ {\rm Max~JD} = 2444119.43 + 32\fday333 \times E, $$
that are used in Figure 1 for plotting our data. The accuracy of the individual observations is near 0\fmm 01 in all filters. It is obvious that these elements are not valid, and if RV Nor is periodic variable, it is most probably an RVTAU type star with a period near twice of above one.
Using Harris' (1980) observations, we obtained the following ephemeris:
$$ {\rm Min~JD} = 2444138.5 + 64\fday77 \times E. $$
This ephemeris is used in Figure 2.}

\IBVSTack{
The research described here was supported in part by the Russian Foundation of Basic Research and the State Science and Technology Program ``Astronomy'' to LNB and through NSERC Canada to DGT. We would also like to express our gratitude to the administrations of SAAO for allocating a large amount of observing time.}

\IBVS2fig{7.5cm}{4725-f1.ps}{Observations obtained before and after JD 2451270 identified by circles and dots respectively.}{4725-f2.eps}{Small circles and dots represent our observations, large circles represent data from Harris (1980), whose intermediate-band measurements were converted to  $V-I_c$, using formulae from Coulson et al.\ (1985).}

\references

Coulson, I.M., Caldwell, J.A.R., \& Gieren, W.P., 1985,
{\it Astrophys.\ J.\ Suppl.\ Ser.}, {\bf 57}, 595

Harris, H., 1980, Ph.D. Thesis., University of Washington


\IBVSedata{4725-t1.txt}

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