Doubling of minute-long Quasi-Periodic Pulsations from super-flares on a low mass star |
|
Nived Vilangot Nhalil Submitted: 2022-06-17 10:40
Using the ULTRASPEC instrument mounted on the 2.4-m Thai National Telescope, we observed two large flares, each with a total energy close to 1034 erg with sub-second cadence. A combination of a wavelet analysis, a Fourier transform plus an empirical mode decomposition, reveals quasi-period pulsations (QPP) which exhibit an apparent doubling of the oscillation period. Both events showed oscillations of a few minutes over a interval of several minutes, and despite the availability of sub-second cadence, there was no evidence of sub-minute oscillations. The doubling of the QPP periods and shorter lifetime of shorter-period QPP modes strongly favour resonant dynamics of magnetohydrodynamic waves in a coronal loop. We estimate loop lengths to be 0.2-0.7 R*, in agreement with a typical length of solar coronal loops. These observations presents rare and compelling evidence for the presence of compact plasma loops in a stellar corona.
Authors: J. Gerry Doyle, Puji Irawati, Dmitrii Y. Kolotkov, Gavin Ramsay, Nived Vilangot Nhalil, Vik S. Dhillon, Tom R. Marsh, Ram Kesh Yadav
Projects: None
|
Publication Status: MNRAS (accepted)
Last Modified: 2022-06-21 11:12
|
 
 
 
 
|
|