Peremennye Zvezdy

Article in PDF
"Peremennye Zvezdy",
Prilozhenie,
vol. 9, N 24 (2009)

New Variable Stars in the Field of GRB 080605

T. Kryachko#1, A. Samokhvalov#2, D. Denisenko#3, B. Satovskiy#1
#1. Astrotel Observatory, Karachay-Cherkessia, Russia;
#2. Surgut, Russia;
#3. Space Research Institute (IKI), Russian Academy of Sciences, Moscow, Russia

ISSN 2221–0474

Received:   21.06.2009;   accepted:   23.09.2009
(E-mail for contact: bredfild@mail.ru, sav@surgut.ru, denis@hea.iki.rssi.ru, bs25@mail.ru)

#NameOtherCoord (J2000)TypeMaxMinSystemPeriodEpoch (JD)typeSpCommentL.CurveFind.ChartData
1 USNO-A2.0 0900-0984839517 28 20.12, +03 33 17.2EW16.0116.25 0.277282454921.4391min Comm. 101_PC-R.png01_ch.jpg01_data.txt
2 GSC 0409-00817, USNO-A2.0 0900-0985131617 28 25.64, +04 14 33.6BY:13.6313.74 1.5922454884.04max Comm. 202_PC-R.png02_ch.jpg02_data.txt
3 USNO-A2.0 0900-0985508217 28 32.78, +03 51 29.9BY:13.7413.77 0.94552454672.7438max Comm. 303_PC-R.png03_ch.jpg03_data.txt
4 GSC 0409-01749, USNO-A2.0 0900-0985685117 28 36.22, +04 14 19.4BY:13.8813.93 0.79642454882.8226max Comm. 404_PC-R.png04_ch.jpg04_data.txt
5 USNO-A2.0 0900-0985843517 28 39.22, +03 55 18.6EW14.8215.00 0.678962454883.0814min Comm. 505_PC-R.png05_ch.jpg05_data.txt
6 USNO-A2.0 0900-0985951717 28 41.40, +03 22 54.8ELL:14.5814.65 0.69502454672.4168min Comm. 606_PC-R.png06_ch.jpg06_data.txt
7 USNO-A2.0 0900-0986400317 28 49.90, +03 52 43.7EB16.1616.34 0.692532454927.5215min Comm. 707_PC-R.png07_ch.jpg07_data.txt
8 USNO-A2.0 0900-0986881517 28 59.09, +04 03 34.4EW16.8417.25 0.249722454945.5460min Comm. 808_PC-R.png08_ch.jpg08_data.txt
9 USNO-A2.0 0900-0988450117 29 28.96, +03 29 33.8EW15.7616.02 0.386792454928.5213min Comm. 909_PC-R.png09_ch.jpg09_data.txt
10 USNO-A2.0 0900-0988565117 29 31.22, +04 07 57.1EW14.4514.85 0.395712454920.4900min Comm. 1010_PC-R.png10_ch.jpg10_data.txt
11 USNO-A2.0 0900-0988885117 29 37.66, +03 46 27.0EW16.1116.55 0.355492454927.4836min Comm. 1111_PC-R.png11_ch.jpg11_data.txt
12 USNO-A2.0 0900-0989007717 29 40.10, +04 09 33.0EW17.1317.52 0.314492454948.4403min Comm. 1212_PC-R.png12_ch.jpg12_data.txt
13 USNO-B1.0 0936-030388417 30 10.69, +03 36 20.2EB17.0317.51 0.329332454948.4393min Comm. 1313_PC-R.png13_ch.jpg13_data.txt
14 GSC 0422-00012, USNO-A2.0 0900-0991205517 30 23.52, +04 08 54.1EB13.2213.30 0.759922454921.5135min Comm. 1414_PC-R.png14_ch.jpg14_data.txt
15 USNO-A2.0 0900-0991262117 30 24.60, +03 49 50.9RRAB16.5017.82 0.464082454948.4688max Comm. 1515_PC-R.png15_ch.jpg15_data.txt
16 USNO-A2.0 0900-0991773117 30 33.76, +03 29 17.6EW16.9117.26 0.309502454920.5006min Comm. 1616_PC-R.png16_ch.jpg16_data.txt
17 USNO-A2.0 0900-0993360117 31 01.84, +03 35 01.8EB15.0815.39 0.372432454928.4379min Comm. 1717_PC-R.png17_ch.jpg17_data.txt
18 USNO-A2.0 0900-0994716317 31 24.98, +03 22 31.0BY:14.5514.59 12.52454683.63max Comm. 1818_PC-R.png18_ch.jpg18_data.txt

Comments:


1. Primary minima: HJD(TT) 2454921.4391, 2454934.4677. Min II = 16.23.

2. Infrared colors J-H = 0.315, H-K = 0.063 (2MASS) are consistent with an early G spectral type (Bessell and Brett 1988). The variability type is very uncertain, we suggest one of the possibilities.

3. Infrared colors J-H = 0.534, H-K = 0.12 (2MASS) are consistent with an early K spectral type (Bessell and Brett 1988) and with the BY classification.

4. Infrared colors J-H = 0.536, H-K = 0.112 (2MASS) are consistent with an early K spectral type (Bessell and Brett 1988) and with the BY classification.

5. Min II = 14.99.

6. A close pair of stars 2MASS 17284130+0322552 and 2MASS 17284149+0322536. The angular resolution of our telescope is insufficient to determine which of the two stars varies. The coordinates in the table are for the blend of the two stars from the USNO-A2.0 catalogue.

7. Primary minimum: HJD(TT) 2454927.5215. Min II = 16.25.

8. Min II = 17.19.

9. A close pair of stars 2MASS 17292890+0329321 and 2MASS 17292891+0329360. The angular resolution of our telescope is insufficient to determine which of the two stars varies. The coordinates in the table are for the blend of the two stars from the USNO-A2.0 catalogue. Primary minimum: HJD(TT) 2454928.5213. Min II = 15.98.

10. Primary minima: HJD(TT) 2454920.4900, 2454935.5254. Min II = 14.77.

11. Primary minima: HJD(TT) 2454927.4836, 2454933.5333, 2454948.4610. Min II = 16.51.

12. Primary minima: HJD(TT) 2454920.4527, 2454942.4692, 2454948.4403. Min II = 17.46.

13. Primary minima: HJD(TT) 2454920.4503, 2454921.4351, 2454948.4393. Min II = 17.27.

14. Primary minima: HJD(TT) 2454921.5135, 2454934.4366. Min II = 13.26.

15. Maxima: HJD(TT) 2454921.5523, 2454928.5162, 2454935.4762, 2454948.4688, 2454949.4000.

16. Primary minima: HJD(TT) 2454920.5006, 2454933.4966, 2454934.4249. Min II = 17.19.

17. Primary minimum: HJD(TT) 2454928.4379. Min II = 15.26.

18. Infrared colors J-H = 0.394, H-K = 0.137 (2MASS) are consistent with an early K spectral type (Bessell and Brett 1988) and with the BY classification.

Remarks:
During observations of the field of GRB 080605 (Sbarufatti et al. 2008), we discovered 18 new variable stars. Our observations were carried out at Astrotel-Caucasus observatory using the 300-mm Ritchey-Chretien telescope, equipped with an unfiltered Apogee Alta U9000 CCD camera. A total of 527 images with 5-minute exposures were obtained on JD 2454672 - 2454954. For basic reductions for dark current, flat fields, and bias, we used IRAF routines. For search and photometry of new variable stars, we applied VaST software by Sokolovsky and Lebedev (2005). The comparison star was GSC 0418-001697 = USNO-B1.0 0936-0304538 (17:30:50.65, +03:41:37.1, J2000; R1 = 13.39 ,R2 = 13.30). Unfiltered magnitudes were calibrated using the comparison star, assuming Rcomp = 13.345. The coordinates of the variable stars in the table were drawn from the 2MASS catalogue (Cutri et al. 2003) except for the star USNO-A2.0 0900-09912621 (missing in the 2MASS catalogue) and the stars USNO-A2.0 0900-09859517 and USNO-A2.0 0900-09884501 (see the Comments); their coordinates were drawn from the USNO-A2.0 catalogue (Monet et al. 1998). For search for periods and epochs of extrema, we use Peranso software (www.peranso.com)


Acknowledgements: We would like to thank S. V. Antipin and N. N. Samus for helpful discussion.

References:
Bessell, M.S., Brett, J.M., 1988, PASP, 100, 1134
Cutri, R.M., Skrutskie, M.F., van Dyk, S., et al., 2003, 2MASS All Sky Catalog of Point Sources, Centre de Donnees Astronomiques de Strasbourg, II/246
Monet, D., Bird, A., Canzian, B., et al., 1998, USNO-A2.0, A Catalog of Astrometric Standards (U.S. Naval Observatory, Washington, DC), Centre de Donnees Astronomiques de Strasbourg, I/252
Sbarufatti, B., Barthelmy, S.D., Burrows, D.N., et al., 2008, GRB Coordinates Network Circular, No. 7828
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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