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Detection of Flare Stars in TAOS 2-year Data

ATel #2035; D.-W. Kim, P. Protopapas, C. Alcock, Y.-I. Byun, Z.-W. Zhang, J.-H. Wang, S.-K. King, C. Y. Wen, M. J. Lehner, F. B. Bianco, N. K. Coehlo, S. Mondal, T. Axelrod, W. P. Chen, K. H. Cook, R. Dave, I. de Pater, R. Porrata, T. Lee, H.-C. Lin, J. J. Lissauer, S. L. Marshall, J. A. Rice, M. E. Schwamb, S. Y. Wang
on 28 Apr 2009; 16:30 UT
Credential Certification: Dae-Won Kim (dakim@cfa.harvard.edu)

Subjects: Optical, Star

   We analyzed 2 years of data from the Taiwan-American Occultation Survey (TAOS, Lehner et al. 2009), accumulated during 2005 and 2006, and found 3 flare stars. All of them are known x-ray sources. Among the detected flare stars, 1RXS J044712.8+203809 shows three recurrences of flare events within a month. We summarize our findings with links to VizieR and to the light-curves in the table below.

   Generally flare stars, and also the ones reported here, are M type dwarfs and also x-ray sources. They occasionally show a rapid increase in brightness followed by an exponential decay, which we call 'flare events' (see light curves).

   We used the PDT (Kim et al. 2008) to de-trend the light-curves because the TAOS data usually show strong trends (flux variations correlated among several stars in the field) due to a combination of weather patterns, photometry defects etc. The links to the light-curves in the table show the combined light-curves of telescopes (telescopes A, B and D) after de-trending. The links also show the light-curves for each telescope before and after de-trending. To detect events, such as flare stars shown here, we used the method developed by Preston et al. (see Preston et al. 2008).

ID
(#)
RA
(h:m:s)
Dec
(d:m:s)

USNOB1.0 & ROSAT ID
(VizieR link)

Spectral Type Date of detection
(Light-Curve link)
1 04:47:12.2 +20:38:11

1106-0057012
1RXS J044712.8+203809

M3

2006/10/02
2006/10/20
2006/10/29

2 04:09:18.2 +17:59:55

1079-0058056
1RXS J040918.0+180008

K8 2006/08/12
3 17:27:19.5 +27:09:01

1171-0322166
1RXS J172719.4+270858

Unknown 2006/04/03