Comments:
1. Period 0d.3351 is also possible. Primary minima:
| HJD(TT) | ± |
| 2455477.8099 |
0.0008 |
| 2455481.8315 | 0.0007 |
| 2455483.8408 |
0.0007 |
MinII=14m.36.
2. Periods 0d.3053 or 0d.4396 are also possible. MinII=16m.65.
3. Primary minima:| HJD(TT) | ± |
|
2455478.8477 | 0.0008 |
| 2455483.8329 | 0.0005 |
MinII=15m.66.
4. A close pair of two stars: USNO-A2.0 0525-03533089 and USNO-A2.0 0525-03533312.
USNO-A2.0 0525-03533089 varies.
5. Maxima:| HJD(TT) | ± |
| 2455480.8375 |
0.0007 |
| 2455481.8357 | 0.0009 |
| 2455482.8317 | 0.0007 |
6. Maxima:| HJD(TT) | ± |
|
2455475.6092 | 0.0008 |
| 2455481.5989 | 0.0008 |
7. Periods 1d.6383 or 2d.47 are also possible. Infrared colors
J–H=0.537, H–K=0.127, J–K=0.664 (2MASS) are consistent with the
K spectral type (Bessell
and Brett 1988) and BY: classification.
Remarks:
During observations of two fields in the southern hemisphere (see the following table)
we discovered
seven new variable stars.
| Field |
α |
δ |
Number of images |
JD start |
JD end |
| 1 |
06h 50m 29s |
–36° 11′ 01″ |
316 |
2455475 |
2455486 | |
| 2 |
23h 12m 35s |
–28° 30′ 31″ |
486 |
2455475 |
2455486 |
Our observations were carried out in Tolar Grande, Argentina, using the 80-mm
f/6 ED refractor, equipped with an unfiltered SBIG ST-2000XM CCD camera.
All images were taken with 5-minute exposure times.
For basic reductions for dark current, flat fields and bias we used MaxIm DL software.
For search and photometry of new variable stars, we applied VaST software by Sokolovsky
and Lebedev (2005).
The comparison stars for two fields were the following:
| Field |
Comparison star |
α |
δ |
R1 |
R2 |
Rcomp |
| 1 |
USNO-A2.0 0525-03545983 |
06h 50m 29s.28 |
–36° 22′ 17″.2 |
13m.47 |
13m.33 |
13m.40 | |
| 2 |
USNO-A2.0 0600-44465807 |
23h 13m 40s.95 |
–28° 21′ 34″.6 |
12m.45 |
12m.44 |
12m.445 | |
The coordinates of the variable and comparison stars in the tables were drawn from
the 2MASS catalogue
(Skrutskie et al. 2006). The R1 and R2 magnitudes of the comparison
stars were drawn from the USNO-B1.0 catalogue (Monet et al. 2003). Unfiltered magnitudes
were calibrated using the
Rcomp magnitudes from the last table. For search
for periods and epochs of extrema, we use Peranso software (www.peranso.com).
Acknowledgements: We would like to thank S. V. Antipin for helpful
discussion.
References:
Bessell, M.S., Brett, J.M., 1988, PASP, 100, 1134
Monet, D.G., Levine, S.E., Casian, B., et al., 2003, Astron. J., 125, 984
Skrutskie, M.F., Cutri, R.M., Stiening, R., et al., 2006, Astron. J., 131, 1163
Sokolovsky, K., Lebedev, A., 2005, in 12th Young Scientists' Conference on Astronomy
and Space Physics, Kyiv, Ukraine, April 19-23, 2005, eds.: Simon, A.; Golovin, A.,
p.79
