Multi-wavelength quasi-periodic pulsations in a stellar superflare

Abstract

We present the first multi-wavelength simultaneous detection of QPP in a superflare (more than a thousand times stronger than known solar flares) on a cool star, in soft X-rays (SXR, with XMM-Newton) and white light (WL, with Kepler). It allowed for the first-ever analysis of oscillatory processes in a stellar flare simultaneously in thermal and non-thermal emissions, conventionally considered to come from the corona and chromosphere of the star, respectively. The observed QPP have periods $1.5\pm 0.15$ hours (SXR) and $3\pm 0.6$ hours (WL), and correlate well with each other. The unique relationship between the observed parameters of QPP in SXR and WL allowed us to link them with oscillations of the electric current in the flare loop, which directly affect the dynamics of non-thermal electrons and indirectly (via Ohmic heating) the thermal plasma. These findings could be considered in favour of the equivalent LCR-contour model of a flare loop, at least in the extreme conditions of a stellar superflare.

Accepted for publication in ApJ Letters

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Cited by in corpus (5)

• Exploring the origin of multi-periodic pulsations during a white-light flare
• Very long-periodic pulsations detected simultaneously in a white-light flare and sunspot penumbra
• Doubling of minute-long Quasi-Periodic Pulsations from super-flares on a low mass star
• Detecting fast-variation pulsations in solar hard X-ray and radio emissions
• Modulation depth of the gyrosynchrotron emission as identifier of fundamental sausage modes