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[vsnet-newvar 1857] New variables in the fields of FG Ser, LT Del and QW Sge



Dear colleagues,

I examined VRI photometry of the fields of Draco C-1, ER
Del, LT Del, FG Ser, IV Vir and QW Sge taken with 40cm
telescope at Brno observatory in 2002 (some data were taken
together with Petr Sobotka and Jan Skalicky). The images
were processed automatically with respect to comparison
stars measured by
Henden (Henden & Munari 2000). The field photometry was
searched for new variable stars using algorithm described
e.g. in Pojmanski, 2000 (astro-ph/0005236), and implemented
in VARFIND by Lukas Kral
(http://kral.astronomy.cz/soft/varfind/).

In my previous emails I introduced weird filter "Vc". This
is a mistake and it should be corrected to "V". It was a bug
in my magnitude processing code.

4 new variable stars and one suspected variable were found.

Pej 014 in the field of FG Ser
RA = 18:15:31.5, Dec = -00:22:34, USNO A2.0 gives B-R = 3.3
mag
The colour and amplitude of light changes suggest a Mira
type star:
20020519.0030  10.76Ic
20020603.9697  10.47Ic
20020705.9080  10.08Ic
20020722.8664  10.08Ic
20020727.8488  10.05Ic
20020819.8352  10.09Ic
20020830.8149  10.18Ic
20021026.7408  10.94Ic
20020519.0044  13.14Rc
20020603.9708  12.96Rc
20020705.9091  12.46Rc
20020722.8672  12.52Rc
20020727.8486  12.44Rc
20020819.8350  12.46Rc
20020830.8147  12.50Rc
20021026.7406  13.47Rc

Pej 015 in the field of FG Ser
RA = 18:14:58.6, Dec = -00:23:00.4, USNO A2.0 gives B-R =
2.8 mag
This looks like some kind of longer period red variable
either Mira or SR.
20020519.0030  11.85Ic
20020603.9697  11.89Ic
20020705.9080  11.82Ic
20020722.8664  11.87Ic
20020727.8488  11.93Ic
20020819.8352  11.94Ic
20020830.8149  12.01Ic
20021026.7408  12.29Ic
20020519.0044  13.56Rc
20020603.9708  13.70Rc
20020705.9091  13.60Rc
20020722.8672  13.78Rc
20020727.8487  13.82Rc
20020819.8350  13.74Rc
20020830.8147  14.05Rc
20021026.7406  14.27Rc

Pej 016 in the field of LT Del
RA = 20:35:44.4, Dec = +20:06:57, USNO A2.0 gives B-R = 2.7
mag
Almost complete cycle of this bright star has been catched.
The period is approx. 240 days and thus a low amplitude Mira
or higher amplitude SR.
20020519.0114  9.33Ic
20020603.9879  9.72Ic
20020705.9602  10.49Ic
20020723.0397  10.71Ic
20020727.9947  10.70Ic
20020819.9925  10.75Ic
20020830.9169  10.57Ic
20021026.8903  9.50Ic
20030105.7287  9.22Ic
20020519.0130  11.45Rc
20020603.9900  12.01Rc
20020705.9614  13.08Rc
20020723.0411  13.31Rc
20020727.9946  13.33Rc
20020819.9924  13.34Rc
20020830.9167  13.15Rc
20021026.8902  11.53Rc
20021231.7910  11.01Rc
20030105.7285  11.18Rc
20020519.0150  13.54V
20020603.9922  14.32V
20021026.8900  13.43V
20030105.7282  13.05V

Pej 017 in the field of QW Sge
RA = 19:45:31.3, Dec = +18:37:12, USNO A2.0 gives B-R = 3.1
mag
The light curve is little bit messy due to the faintness of
the star, the colour suggest low amplitude SR. Only I band
data are useful, the star is invisible on V band images and
barely visible on R band images.
20020604.0544  12.43Ic
20020706.0628  12.35Ic
20020722.9488  12.76Ic
20020727.9822  12.65Ic
20020819.9785  12.57Ic
20020830.9027  12.77Ic
20021026.8764  12.74Ic
20030105.7132  12.58Ic

Finally I would like to draw your attention to GSC 3895:1630
in the field of Draco C-1. This star is variable on I and R
band images with light curve of shorter period (though not
_very_ short - maybe on the order of few days). The problem
is that there is a close companion to this star on my images
(I guess some 5 arcsec away) and thus hampering the
photometry. The star is quite blue (R-I ~ 0.4). Could this
be a cepheid star in the Draco galaxy?

Best regards,

Ondrej Pejcha


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