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arXiv · 1412.6109

Kepler Flares III: Stellar Activity on GJ 1245 A and B

John C. Lurie·James R. A. Davenport·Suzanne L. Hawley·Tessa D. Wilkinson·John P. Wisniewski·Adam F. Kowalski·Leslie Hebb
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Abstract

We present the flare occurrence rates and starspot evolution for GJ 1245 A and B, two active M5 stars, based on nine months of Kepler short cadence observations, and four years of nearly continuous long cadence observations. The A component is separated from the B component by 7 arcseconds, and the stars are not resolved in the Kepler pipeline processing due to Kepler's large plate scale of 4 arcseconds/pixel. Analyzing the target pixel data, we have generated separate light curves for components A and B using the PyKE pixel response function modeling procedures, and note the effects of CCD saturation and non-linear response to high energy flares. In our sample, GJ 1245A and B exhibit an average of 3.0 and 2.6 flares per day, respectively. We introduce a new metric, $L_{fl}/L_{\mathrm{Kp}}$, to compare the flare rates between stars, and discuss this in the context of GJ 1245 A and B. Both stars exhibit starspot features that evolve on long time scales, with the slower rotating B component showing evidence of differential rotation. Intriguingly, the angular separation between the A and B component photocenters decreases during the four years of observations in a manner consistent with a shift in the position of the A photocenter due to the orbit of its unseen M8 companion (GJ 1245C), which is $\sim$94% less bright. Among the most detailed photometric studies of fully convective M dwarfs in a multiple system, these results provide an important constraint on stellar age-rotation-activity models.

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John C. Lurie, James R. A. Davenport, Suzanne L. Hawley, Tessa D. Wilkinson, John P. Wisniewski, Adam F. Kowalski, Leslie Hebb. 2014-12-18. Kepler Flares III: Stellar Activity on GJ 1245 A and B. https://doi.org/10.1088/0004-637x%2F800%2F2%2F95

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