2005A&A...436.1041M


C.D.S. - SIMBAD4 rel 1.7 - 2020.12.03CET18:23:05

2005A&A...436.1041M - Astronomy and Astrophysics, volume 436, 1041-1047 (2005/6-4)

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

MITRA-KRAEV U., HARRA L.K., WILLIAMS D.R. and KRAEV E.

Abstract (from CDS):

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 (0.2-12keV) is investigated with wavelet analysis. The flare's extended, flat peak shows clear evidence for a damped oscillation with a period of around 750s, an exponential damping time of around 2000s, 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)x1010cm. The local magnetic field strength is found to be 105±50G. 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.

Abstract Copyright:

Journal keyword(s): stars: coronae - stars: flare - stars: magnetic fields - stars: oscillations - X-rays: stars - stars: individual: AT Mic

Simbad objects: 5

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Number of rows : 5

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 V* II Tau Er* 03 49 43.2748760121 +24 19 04.494143673   15.798 14.185 14.021   M4.6V 69 0
2 BD+20 2465 Er* 10 19 36.2808024653 +19 52 12.014037746   10.82 9.52 9.19   dM3 1163 0
3 V* AT Mic Er* 20 41 51.15925 -32 26 06.8283 12.753 11.909 10.343 9.098 7.383 M4.5Ve+M4.5Ve 330 0
4 V* AT Mic B PM* 20 41 51.1600872316 -32 26 10.209854590   12.64 11.34 10.79   M4.5Ve 76 0
5 HD 224085 RS* 23 55 04.0516465022 +28 38 01.248194500 8.88 8.20   6.9   K2+IVeFe-1 686 0

    Equat.    Gal    SGal    Ecl

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2020.12.03-18:23:05

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