A Multi-Period Oscillation in a Stellar Superflare

Abstract

Flares that are orders of magnitude larger than the most energetic solar flares are routinely observed on Sun-like stars, raising the question of whether the same physical processes are responsible for both solar and stellar flares. In this letter we present a white-light stellar superflare on the star KIC9655129, observed by NASA's Kepler mission, with a rare multi-period quasi-periodic pulsation (QPP) pattern. Two significant periodic processes were detected using the wavelet and autocorrelation techniques, with periods of 78 +/- 12 min and 32 +/- 2 min. By comparing the phases and decay times of the two periodicities, the QPP signal was found to most likely be linear, suggesting that the two periodicities are independent, possibly corresponding either to different magnetohydrodynamic modes of the flaring region, or different spatial harmonics of the same mode. The presence of multiple periodicities is a good indication that the QPPs were caused by magnetohydrodynamic oscillations, and suggests that the physical processes in operation during stellar flares could be the same as those in solar flares.

Accepted by The Astrophysical Journal Letters (October 2015). 8 pages with 5 figures

References in corpus (4)

• The first observed stellar X-ray flare oscillation: Constraints on the flare loop length and the magnetic field
• GALEX high time-resolution ultraviolet observations of dMe flare events
• On the Periodicity of Oscillatory Reconnection
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Cited by in corpus (17)

• The Kepler Catalog of Stellar Flares
• Modelling Quasi-Periodic Pulsations in Solar and Stellar Flares
• Quasi-periodic pulsations in solar and stellar flares: an overview of recent results
• Slow-Mode Magnetoacoustic Waves in Coronal Loops
• A large-scale search for evidence of quasi-periodic pulsations in solar flares
• Statistical Properties of Quasi-Periodic Pulsations in White-Light Flares Observed With Kepler
• Stellar flares observed in long cadence data from the Kepler mission
• Observation of a Quasi-periodic Pulsation in Hard X-ray, Radio and Extreme-ultraviolet Wavelengths
• A blueprint of state-of-the-art techniques for detecting quasi-periodic pulsations in solar and stellar flares
• Quasi-periodic pulsations in the most powerful solar flare of Cycle 24
• Observation of a Short Period Quasi-Periodic Pulsation in Solar X-ray, Microwave and EUV Emissions
• New Time-Resolved, Multi-Band Flares In The GJ 65 System With gPhoton
• Multi-wavelength quasi-periodic pulsations in a stellar superflare
• Multi-waveband detection of quasi-periodic pulsations in a stellar flare on EK Draconis observed by XMM-Newton
• Possible evidence of induced repetitive magnetic reconnection in a superflare from a young solar-type star
• Slow Magnetoacoustic Oscillations in Stellar Coronal Loops
• Young M dwarfs flare activity model: Towards better exoplanetary atmospheric characterisation