Premium
Detection of high‐frequency optical oscillation during the flare phase of EV Lac in 1999
Author(s) -
Contadakis M. E.,
Avgoloupis S.,
Seiradakis J.,
Zhilyaev B. E.,
Romanyuk Ya. O.,
Verlyuk I. A.,
Svyatogorov O. A.,
Khalack V. R.,
Sergeev A. V.,
KonstantinovaAntova R. K.,
Antov A. P.,
Bachev R. S.,
Alekseev I. Y.,
Chalenko V. E.,
Shakhovskoy D. N.
Publication year - 2004
Publication title -
astronomische nachrichten
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.394
H-Index - 63
eISSN - 1521-3994
pISSN - 0004-6337
DOI - 10.1002/asna.200310250
Subject(s) - flare , physics , astrophysics , flare star , light curve , brightness , amplitude , oscillation (cell signaling) , stars , phase (matter) , astronomy , solar flare , observatory , optics , t tauri star , k type main sequence star , quantum mechanics , biology , genetics
A program of Many‐sites Multi Channel simultaneous observations of flare stars by a network of telescops was initiated in 1998. The purpose of this program is to investigate the fine structure of the flares light‐curve in UBVRI, depressing atmospheric and instrumental noises. In this paper we present the results of the observations on the Flare star EV Lac in the B color, which were carried out at the Stephanion observatory during the campaign of 1999. Discrete Fourier Transform analysis of the B‐light curve of the largest flares reveal the presence of high frequency small amplitude oscillations with periods ranging between 6.9 sec and 20 sec in around the flare maximum phase. The oscillation amplitude ranges from 1.4 to 2.6 % of the star brightness in accordance with the results of the campaign of 1998 (Zhilyaev et al. 2000). In addition there is a tendency the higher frequencies to persist in the late phases of the flare evolution. The observations are consistent with the phenomenology of the evolution of a fast mode magneto‐acoustic wave generated at the impulsive phase of the flare and traveling through the magnetic loop. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)