The first observed stellar X-ray flare oscillation: Constraints on the flare loop length and the magnetic field

Abstract

We present the first X-ray observation of an oscillation during a stellar flare. The flare occurred on the active M-type dwarf AT Mic and was observed with XMM-Newton. The soft X-ray light curve (0.2-12 keV) is investigated with wavelet analysis. The flare's extended, flat peak shows clear evidence for a damped oscillation with a period of around 750 s, an exponential damping time of around 2000 s, and an initial, relative peak-to-peak amplitude of around 15%. We suggest that the oscillation is a standing magneto-acoustic wave tied to the flare loop, and find that the most likely interpretation is a longitudinal, slow-mode wave, with a resulting loop length of (2.5 +- 0.2) e10 cm. The local magnetic field strength is found to be (105 +- 50) G. These values are consistent with (oscillation-independent) flare cooling time models and pressure balance scaling laws. Such a flare oscillation provides an excellent opportunity to obtain coronal properties like the size of a flare loop or the local magnetic field strength for the otherwise spatially-unresolved star.

Accepted by A&A (03/12/2005)

Cited by in corpus (29)

• X-Ray Spectroscopy of Stars
• Statistical properties of superflares on solar-type stars based on 1-min cadence data
• Persistent Doppler shift oscillations observed with HINODE/EIS in the solar corona: spectroscopic signatures of Alfvenic waves and recurring upflows
• Quasi-periodic pulsations in solar and stellar flares: an overview of recent results
• Above-the-loop-top Oscillation and Quasi-periodic Coronal Wave Generation in Solar Flares
• Slow-Mode Magnetoacoustic Waves in Coronal Loops
• The corona of HD 189733 and its X-ray activity
• Stellar flares observed in long cadence data from the Kepler mission
• The variability timescales and brightness temperatures of radio flares from stars to supermassive black holes
• GALEX high time-resolution ultraviolet observations of dMe flare events
• The periodic variations of a white-light flare observed with ULTRACAM
• Oscillations in stellar superflares
• Pulsations in the Earth's Lower Ionosphere Synchronized with Solar Flare Emission
• A blueprint of state-of-the-art techniques for detecting quasi-periodic pulsations in solar and stellar flares
• Plasma sloshing in pulse-heated solar and stellar coronal loops
• Giant white-light flares on fully convective stars occur at high latitudes
• Photospheric and chromospheric activity in V405 And: An M dwarf binary with components on the two sides of the full convection limit
• Role of Compressive Viscosity and Thermal Conductivity on the Damping of Slow Waves in the Coronal Loops With and Without Heating-Cooling Imbalance
• TESS observations of flares and quasi-periodic pulsations from low mass stars and potential impact on exoplanets
• Validation of a Scaling Law for the Coronal Magnetic Field Strengths and Loop Lengths of Solar and Stellar Flares
• Role of Non-Ideal Dissipation with Heating-Cooling Misbalance on the Phase Shifts of Standing Slow Magnetohydrodynamic Waves
• Application of a magnetic-field-induced transition in Fe X to solar and stellar coronal magnetic field measurements
• Lower-than-expected flare temperatures for TRAPPIST-1
• Oscillatory reconnection and waves driven by merging magnetic flux ropes in solar flares
• Multi-wavelength quasi-periodic pulsations in a stellar superflare
• ROME (Radio Observations of Magnetized Exoplanets). II. HD 189733 Does Not Accrete Significant Material from its Exoplanet like a T Tauri Star from A Disk
• Astrophysics in 2005
• Slow Magnetoacoustic Oscillations in Stellar Coronal Loops
• Splinter Session "Solar and Stellar Flares"