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\IBVShead{4479}{22 May 1997}

\centerline{\ft FUOR V1057 Cyg - TWO YEARS IN LOCAL MINIMUM}
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   The star V1057 Cyg belongs to a small-number group of eruptive
FU Orionis variables or Fuors (Herbig 1977; Hartmann et al.
1993). Since peak light in 1970 the light curve of the Fuor V1057
Cyg exhibits most remarkable and dynamic changes in comparison
with more quiescent behavior in post-outburst stage of two other
best-studied Fuors FU Ori and V1515 Cyg. Over the period 1970-1994 
V1057 Cyg had declined by about of 3.5 mag in B (Figure 1). In
contrast, FU Ori and V1515 Cyg have a much slower declining
rates. Throughout post-outburst states both FU Ori and V1515 Cyg
have faded by 1.1 (1937-1994) and 0.3 mag (1974-1994) in B,
respectively. Moreover, in 1995 V1057 Cyg had suddenly dimmed by
0.8 mag in B (Ibrahimov 1996). Note that the 1995 drop in
magnitude of V1057 Cyg is similar to the 1980 one of V1515 Cyg. In
1996 the observations of V1057 Cyg were continued at Mt.
Maydanak observatory. These observations have been obtained
using the same equipment as described in Ibrahimov (1996). These
new observations are combined with existing ones and used to
construct the figures. Figure 1 shows historical pg/B light curve
of the Fuor based on all available data which have been compiled
by the authors and joined with Mt. Maydanak database. Figure 2 shows a 
more detailed V-light curve of the Fuor based on our own
observations in 1995-96. Figure 3 shows the brightness and color
variations of the Fuor in 1978, 1981-96 based only on Mt. Maydanak
observations.

   The figures allow to conclude that the Fuor still remains in
local minimum. The observations of 1995-96 (Figure 2) show that the
star has no visible trend neither to increase nor to following
decrease its brightness. Besides, Figures 2 and 3 indicate the
presence of a gradual increase in the amplitude of light
variations from 0.2V in 1981-91 to 0.5V in 1996. The similar
increases in the amplitudes of light variations are observed in
U, B, and R too. Since mid-eighties to 1996 the amplitudes have
increased from 0.5 to 0.8 in U, from 0.2 to 0.6 in B, and from
0.1 to 0.3 mag in R.

   The evolution of the colors of the Fuor in 1978-96 is most
interesting (Figure 3). Despite the continuation of smoothed
large-scale fading till 1986, the colors had
practically constant values in 1978-86 (cf. the Table in
Ibrahimov 1996). During the next five years 1986-90 the
light curve shows a slight bowl-shaped increase in the
brightness. This increasing light is accompanied by
monotonic decrease of the average value of the U$-$B color
from +1.15 to +1.03 mag. At the same time the other two
colors did not change. Thus, both colors have remained
practically constant during 1978-90: B$-$V = +1.76 and
V$-$R = +1.59 mag. During 1991-94 the light curve of the star
exhibited saw-tooth variations. These variations are out
of phase with similar saw-tooth color variations: i.e.,
redder colors correspond to higher brightness and vice
versa. The 1995 drop in magnitude of V1057 Cyg has led to
common reddening by 0.2-0.3 mag of all three colors of the
star.\vfill \eject

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\centerline{Figure 1. Historical pg/B light curve of V1057 Cyg in 1934-1996}
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\centerline{Figure 2. Detail  V-light curve of V1057 Cyg in 1995-1996}
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\centerline{3}
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\centerline{Figure 3. Brightness and color variations of V1057 Cyg in 1978-1996}


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 Now it can be defined that during the decade since
mid-eighties to 1996 the general changes of the colors are about
of 0.5 mag for U$-$B and about of 0.3 mag for both B$-$V and
V$-$R.

   Thus, we conclude that the new active phase of photometric
changes of the Fuor V1057 Cyg began in 1991. The detected
increase in the amplitude of light variations since 1991,
remarkable behavior of the colors and the 1995 drop in
magnitude of V1057 Cyg provide strong support to the
conclusion. The mentioned changes (except the 1980 drop
in magnitude of V1515 Cyg) have no analogies in the
photometric behavior of the other Fuors. New observations of
the Fuor in this active and interesting state are very
important and useful.

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\beginauthors
\authorsrightcol
V.M. IBRAHIMOVA
M.A. IBRAHIMOV
Astronomical Institute
Astronomical str. 33, Tashkent
700052 Uzbekistan
valery@astro.gov.uz              %email

\endauthors


\references

Herbig, G.H., 1977, {\it Astrophys. J.}, {\bf 217},  693

Hartmann, L.W., Kenyon, S.J., Hartigan, P., in Protostars and
                Planets III, eds. E.H. Levy and J. Lunine,
                Tucson, Univ. Arizona Press, 1993, p.\,497

Ibrahimov, M.A., 1996, {\it IBVS}, No.\,4285

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