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arXiv · 2402.13885

A Dragon's Flame of Many Colours: Multi-wavelength Observations of Flares from the Active M Binary CR Draconis

James A. G. Jackman·Evgenya L. Shkolnik·R. O. Parke Loyd·Tyler Richey-Yowell·Joe Llama·David Boyd·Bob Buchheim·David Iadevaia·Jack Martin·Forrest Sims·Gary Walker·John Wetmore
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Abstract

We present the results of a multi-wavelength Pro-Am campaign to study the behaviour of flares from the active M1.5V star binary CR Draconis. CR Dra was observed with TESS 20-s photometry, Swift near-UV (NUV) grism spectroscopy and with ground-based optical photometry and spectroscopy from a global collaboration of amateur astronomers. We detected 14 flares with TESS and Swift simultaneously, one of which also had simultaneous ground-based photometry and spectroscopy. We used the simultaneous two-colour optical and NUV observations to characterise the temperature evolution of the flare and test the accuracy of using optical data to predict NUV emission. We measured a peak temperature of $7100^{+150}_{-130}$ K for this flare, cooler than the typically assumed 9000 K blackbody model used by flare studies. We also found that the 9000 K blackbody overestimated the NUV flux for other flares in our sample, which we attributed to our Swift observations occurring during flare decays, highlighting the phase-dependence for the accuracy of flare models.

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James A. G. Jackman, Evgenya L. Shkolnik, R. O. Parke Loyd, Tyler Richey-Yowell, Joe Llama, David Boyd, Bob Buchheim, David Iadevaia, Jack Martin, Forrest Sims, Gary Walker, John Wetmore. 2024-02-21. A Dragon's Flame of Many Colours: Multi-wavelength Observations of Flares from the Active M Binary CR Draconis. https://arxiv.org/abs/2402.13885

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