Poster Open Access

AstroSat observations of long-duration X-ray superflares on active M-dwarf binary EQ Peg

Karmakar, Subhajeet

We present a comprehensive study of three large long-duration flares detected on an active M-dwarf binary EQ Peg using Soft X-Ray Telescope of the AstroSat observatory. The peak X-ray luminosities of the flares in the 0.3 -- 7 keV band are found to be within ~4-10 × 10^{30} erg s^{-1}. Spectral analysis indicates the presence of three temperature corona with the first two plasma temperatures remain constant during all the flares and the post-flare. The flare-temperature peaked at 56, 40, and 31 MK, which are 2.5, 1.8, and 1.4 times more than the minimum value, respectively. The peak emission measures are found to be 1.16 -- 5.64 × 10^{53} cm^{-3}, whereas the abundances peaked at 0.7 -- 1.2 times the solar abundances. Using quasi-static loop modeling, we derive loop-lengths for all the flares as 2.7 ± 1.4 × 10^{11}, 3.9 ± 1.5 × 10^{11}, and 6.4 ± 2.4 × 10^{11} cm, respectively. The estimated energies of all three flares are >10^{33-35} erg, putting them in the category of Superflare. All three superflares are also found to be the longest duration flares ever observed on EQ Peg.

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