THE DECAYING LONG-PERIOD OSCILLATION OF A STELLAR MEGAFLARE

被引：49
作者：
Anfinogentov, S. [1 ]
Nakariakov, V. M. [2 ,3 ,4 ]
Mathioudakis, M. [5 ]
Van Doorsselaere, T. [6 ]
Kowalski, A. F. [7 ]
机构：
[1] Inst Solar Terr Phys, Irkutsk, Russia
[2] Univ Warwick, Ctr Fus Space & Astrophys, Dept Phys, Coventry CV4 7AL, W Midlands, England
[3] Kyung Hee Univ, Sch Space Res, Yongin 446701, Gyeonggi, South Korea
[4] Russian Acad Sci, Cent Astron Observ Pulkovo, St Petersburg 196140, Russia
[5] Queens Univ Belfast, Sch Math & Phys, Astrophys Res Ctr, Belfast BT7 1NN, Antrim, North Ireland
[6] Katholieke Univ Leuven, Dept Math, Ctr Math Plasma Astrophys, B-3001 Louvain, Belgium
[7] NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA
来源：
ASTROPHYSICAL JOURNAL | 2013年 / 773卷 / 02期
基金：
欧洲研究理事会;
关键词：
stars: flare; stars: low-mass; stars: oscillations; Sun: oscillations; DOPPLER-SHIFT OSCILLATIONS; BRAGG CRYSTAL SPECTROMETER; X-RAY; MICROWAVE EMISSION; FLARE; SOLAR; STAR; WAVES; PULSATIONS; SUMER;
D O I：
10.1088/0004-637X/773/2/156
中图分类号：
P1 [天文学];
学科分类号：
0704 ;
摘要：
We analyze and interpret the oscillatory signal in the decay phase of the U-band light curve of a stellar megaflare observed on 2009 January 16 on the dM4.5e star YZ CMi. The oscillation is well approximated by an exponentially decaying harmonic function. The period of the oscillation is found to be 32 minutes, the decay time about 46 minutes, and the relative amplitude 15%. As this observational signature is typical of the longitudinal oscillations observed in solar flares at extreme ultraviolet and radio wavelengths, associated with standing slow magnetoacoustic waves, we suggest that this megaflare may be of a similar nature. In this scenario, macroscopic variations of the plasma parameters in the oscillations modulate the ejection of non-thermal electrons. The phase speed of the longitudinal (slow magnetoacoustic) waves in the flaring loop or arcade, the tube speed, of about 230 km s(-1) would require a loop length of about 200 Mm. Other mechanisms, such as standing kink oscillations, are also considered.
引用
收藏
页数：5
相关论文
共 59 条
[11]   FLARES ON THE SUN AND OTHER STARS [J].
HAISCH, B ;
STRONG, KT ;
RODONO, M .
ANNUAL REVIEW OF ASTRONOMY AND ASTROPHYSICS, 1991, 29 :275-324
[12]   X-RAY HEATED MODELS OF STELLAR FLARE ATMOSPHERES - THEORY AND COMPARISON WITH OBSERVATIONS [J].
HAWLEY, SL ;
FISHER, GH .
ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES, 1992, 78 (02) :565-598
[13]   Damped large amplitude transverse oscillations in an EUV solar prominence, triggered by large-scale transient coronal waves [J].
Hershaw, J. ;
Foullon, C. ;
Nakariakov, V. M. ;
Verwichte, E. .
ASTRONOMY & ASTROPHYSICS, 2011, 531
[14]   Microwave, optical, EUV, and hard X-ray signature of possible coronal loop interaction [J].
Huang, GL ;
Ji, HS .
SOLAR PHYSICS, 2005, 229 (02) :227-236
[15]  
HUDSON HS, 1992, PUBL ASTRON SOC JPN, V44, pL77
[16]   SLOW MAGNETOACOUSTIC OSCILLATIONS IN THE MICROWAVE EMISSION OF SOLAR FLARES [J].
Kim, S. ;
Nakariakov, V. M. ;
Shibasaki, K. .
ASTROPHYSICAL JOURNAL LETTERS, 2012, 756 (02)
[17]  
Kliem B, 2000, ASTRON ASTROPHYS, V360, P715
[18]   An "A star" on an M star during a flare within a flare [J].
Kowalski, Adam F. ;
Hawley, Suzanne L. ;
Holtzman, Jon A. ;
Wisniewski, John P. ;
Hilton, Eric J. .
PHYSICS OF SUN AND STAR SPOTS, 2011, (273) :261-264
[19]   A WHITE LIGHT MEGAFLARE ON THE dM4.5e STAR YZ CMi [J].
Kowalski, Adam F. ;
Hawley, Suzanne L. ;
Holtzman, Jon A. ;
Wisniewski, John P. ;
Hilton, Eric J. .
ASTROPHYSICAL JOURNAL LETTERS, 2010, 714 (01) :L98-L102
[20]   Types of Microwave Quasi-Periodic Pulsations in Single Flaring Loops [J].
Kupriyanova, E. G. ;
Melnikov, V. F. ;
Nakariakov, V. M. ;
Shibasaki, K. .
SOLAR PHYSICS, 2010, 267 (02) :329-342
123456