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\IBVShead{4456}{12 March 1997}

\centerline{\ft PHOTOELECTRIC {\large $VI_c$} OBSERVATIONS}
\vspace{0.1in}
\centerline{\ft AND NEW ELEMENTS FOR V399 CARINAE = HR 4110}
\vspace{0.4in}

\begintext

Arellano Ferro (1981) analyzed observations of V399 Car
= HD 90772 = HR 4110, the brightest member --- of spectral type
A7 Ia-O (Turner 1978; see also references cited by Arellano Ferro
1981) --- of the young cluster IC 2581, and found four possible periods
in its power spectrum: 34.87, 40.26, 47.80, and 58.82 days. He noted
that a period of 58.82 days provided the best match of his
observations to those supplied by Madore (1980).

In an attempt to update the ephemeris for the star, we observed it at
CTIO in September-November 1996 using the 1-m reflector. A total
of 18 $VI_c$ measurements were obtained, the accuracy of the
individual data being near $\pm$0\fm 01 in both filters.
The observations are listed in Table 1.

The mean magnitudes of Arellano Ferro's (1981) as well as Cousins'
(1966) observations were coincidenced with our $V$-band data in
order to increase the sample available for a period search. We derived
the following elements:

\vspace{0.15in}
\centerline{Max JD$_{hel}$ = 2450387.4 + 47.2534 $\times$ E.}

\hspace*{2.85in}$\pm$0.4 \hspace*{0.15in}$\pm$0.0027
\vspace{0.15in}

Those elements are used in Figure 1 for plotting the light curve in $V$,
where our observations are identified by large circles and observations
published by Arellano Ferro (1981) and Cousins (1966) are denoted by
small circles and dots, respectively. The shorter period found here appears
to be supported by the rapid change in brightness of the star detected over
our observing season.

\begin{center}
Table 1
\vskip 1mm
\begin{tabular}{cccccc}
\hline
$JD_{hel}$&$V$&$V-I_c$&$JD_{hel}$&$V$&$V-I_c$\\
2450000+ & & & 2450000+ & & \\
\hline
\\
358.8828& 4.684&  .680&383.8107& 4.636&  .681\\
359.8730& 4.693&  .680&384.7948& 4.650&  .691\\
361.8785& 4.705&  .689&386.7912& 4.651&  .674\\
362.8819& 4.694&  .674&387.7955& 4.640&  .680\\
362.8887& 4.702&  .688&388.7856& 4.643&  .690\\
363.8822& 4.699&  .697&390.7897& 4.643&  .689\\
379.8201& 4.661&  .667&391.7781& 4.657&  .676\\
380.8109& 4.635&  .663&392.7720& 4.635&  .679\\
381.8093& 4.665&  .685&393.7821& 4.645&  .684\\
\hline
\end{tabular}
\end{center}

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\centerline{2}
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\centerline{Figure 1}
\vskip 3mm

As a member of the cluster IC\,2581, HR\,4110 has an estimated luminosity
of $M_{V}$ = $-8.8$ (Turner 1978), placing it in the regime of the hypergiant
stars. It is of interest to note that, at the period found here, HR 4110 falls
almost exactly on the period-luminosity relation for pulsating B and A-type
supergiants published several years ago by Maeder \& Rufener (1974;
see also Burki 1978).

The research described here was made possible in part by grants
No. 95--02--05276 and No. 94--02--04347 from the Russian
Foundation of Basic Research to LNB and through NSERC Canada to
DGT.  The authors were Visiting Astronomers at Cerro Tololo
Inter-American Observatory, National Optical Astronomy
Observatories, which is operated by the Association of
Universities for Research in Astronomy, Inc. (AURA) under
co-operative agreement with the National Science Foundation.

\vskip .8cm
\beginauthors
\authorsrightcol
 L.N.~BERDNIKOV
 Sternberg Astronomical Institute
 13, Universitetskij prosp.
 Moscow 119899, Russia
\vskip 2mm 
D.G.~TURNER
 Saint Mary's University
 Halifax, Nova Scotia, B3H 3C3
 Canada
\endauthors
\vskip -4mm

\references

Arellano Ferro, A., 1981, {\it P.A.S.P}, {\bf 93}, 351

Burki, G., 1978, {\it Astron. Astrophys.}, {\bf 65}, 357

Cousins, A.W.J., 1966, {\it Roy. Obs. Bull.}, No.\,122, E59

Madore, B.F., 1980, unpublished

Maeder, A., \& Rufener, F., 1974, {\it IAU Symp.}, No.\,59, 81

Turner, D.G., 1978, {\it Astron. J.}, {\bf 83}, 1081

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