1. A $\Delta R\sim 9.5$ mag Super Flare of An Ultracool Star Detected by $\text{SVOM/GWAC}$ System
- Author
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Xin, L. P., Li, H. L., Wang, J., Han, X. H., Xu, Y., Meng, X. M., Cai, H. B., Huang, L., Lu, X. M., Qiu, Y. L., Wang, X. G., Liang, E. W., Dai, Z. G., Wang, X. Y., Wu, C., Zhang, J. B., Li, G. W., Turpin, D., Feng, Q. C., Deng, J. S., Sun, S. S., Zheng, T. C., Yang, Y. G., and Wei, J. Y.
- Subjects
Astrophysics - Solar and Stellar Astrophysics ,Astrophysics::High Energy Astrophysical Phenomena ,Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics - Abstract
In this paper, we report the detection and follow-ups of a super stellar flare GWAC\,181229A with an amplitude of $\Delta R\sim$9.5 mag on a M9 type star by $\text{SVOM/GWAC}$ and the dedicated follow-up telescopes. The estimated bolometric energy $E_{bol}$ is $(5.56-9.25)\times10^{34}$ ergs, which places the event to be one of the most powerful flares on ultracool stars. The magnetic strength is inferred to be (3.6-4.7) kG. Thanks to the sampling with a cadence of 15 seconds, a new component near the peak time with a very steep decay is detected in the $R$-band light curve, followed by the two-component flare template given by Davenport et al. (2014). An effective temperature of $5340\pm40$ K is measured by a blackbody shape fitting to the spectrum at the shallower phase during the flare. The filling factors of the flare are estimated to be $\sim$30\% and 19\% at the peak time and at 54 min after the first detection. The detection of the particular event with large amplitude, huge-emitted energy and a new component demonstrates that a high cadence sky monitoring cooperating with fast follow-up observations is very essential for understanding the violent magnetic activity., Comment: 14 pages, 12 figures, 4 tables, accepted by ApJ
- Published
- 2020