Peremennye Zvezdy

"Peremennye Zvezdy",
Prilozhenie
,
vol. 11, N 8 (2011)

New Variable Stars in Two Fields in the Southern Hemisphere

T. Kryachko#1, A. Samokhvalov#2, S. A. Korotkiy#3, D. G. Lambas#4
#1. Astrotel Observatory, Karachay-Cherkessia, Russia;
#2. Surgut, Russia;
#3. Ka-Dar Scientific Center and Public Observatory, Moscow, Russia;
#4. Instituto de Astronomía Teórica y Experimental, Conicet-UNC, Córdoba, Argentina

Received:   4.12.2010;   accepted:   11.03.2011
(E-mail for contact: bredfild@mail.ru, sav@surgut.ru, astro_stas@mail.ru, dgl@oac.uncor.edu)


#NameOtherCoord (J2000)TypeMaxMinSystemPeriodEpoch (JD)typeSpCommentL.CurveFind.ChartData
1 USNO-A2.0 0525-0349817606 48 47.75, -36 28 52.9EW14.1:14.36 0.40222455483.8408Min Comm. 101_PC-R.png01_ch.jpg01_data.txt
2 USNO-A2.0 0525-0351869906 49 30.58, -36 20 44.0EW16.4616.65 0.36022455475.8540Min Comm. 202_PC-R.png02_ch.jpg02_data.txt
3 USNO-A2.0 0525-0352882906 49 52.31, -36 31 40.5EW15.3815.68 0.26242455483.8329Min Comm. 303_PC-R.png03_ch.jpg03_data.txt
4 USNO-A2.0 0525-0353308906 50 01.94, -36 29 22.0RRAB16.4816.96 0.62082455476.5083Max Comm. 404_PC-R.png04_ch.jpg04_data.txt
5 USNO-A2.0 0525-0355339306 50 44.55, -36 24 57.5SXPHE16.9617.22 0.082722455481.8357Max Comm. 505_PC-R.png05_ch.jpg05_data.txt
6 USNO-A2.0 0600-4445390223 12 00.44, -28 44 46.1RRAB15.3216.43 0.54502455481.5989Max Comm. 606_PC-R.png06_ch.jpg06_data.txt
7 USNO-A2.0 0600-4446902323 14 07.88, -28 32 01.0BY:13.7613.84 0.71812455475.8984Max Comm. 707_PC-R.png07_ch.jpg07_data.txt

Comments:


1. Period 0d.3351 is also possible. Primary minima:
HJD(TT)±
2455477.8099 0.0008
2455481.83150.0007
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
2455483.83290.0005
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
2455481.83570.0009
2455482.83170.0007


6. Maxima:
HJD(TT)±
2455475.6092 0.0008
2455481.59890.0008


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.
Fieldα 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:
FieldComparison 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



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