2001A&A...374.1072S


Query : 2001A&A...374.1072S

2001A&A...374.1072S - Astronomy and Astrophysics, volume 374, 1072-1084 (2001/8-2)

Microwave plasma emission of a flare on AD Leo.

STEPANOV A.V., KLIEM B., ZAITSEV V.V., FUERST E., JESSNER A., KRUEGER A., HILDEBRANDT J. and SCHMITT J.H.M.M.

Abstract (from CDS):

An intense radio flare on the dMe star AD Leo, observed with the Effelsberg radio telescope and spectrally resolved in a band of 480 MHz centred at 4.85GHz is analysed. A lower limit of the brightness temperature of the totally right handed polarized emission is estimated as Tb∼5x1010K (with values Tb>3x1013K considered to be more probable), which requires a coherent radio emission process. In the interpretation we favour fundamental plasma radiation by mildly relativistic electrons trapped in a hot and dense coronal loop above electron cyclotron maser emission. This leads to densities and magnetic field strengths in the radio source of n∼2x1011cm–3 and B∼800 G. Quasi-periodic pulsations during the decay phase of the event suggest a loop radius of r∼7x108cm. A filamentary corona is implied in which the dense radio source is embedded in hot thin plasma with temperature T≥2x107K and density next≤10–2n. Runaway acceleration by sub-Dreicer electric fields in a magnetic loop is found to supply a sufficient number of energetic electrons.

Abstract Copyright:

Journal keyword(s): stars: activity - stars: flare - stars: coronae - radio continuum: stars - radiation mechanisms: non-thermal - acceleration of particles

Simbad objects: 2

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Number of rows : 2
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
#notes
1 BD+20 2465 Er* 10 19 36.2808181226 +19 52 12.010446571   10.82 9.52 9.19   dM3 1262 0
2 3C 286 Sy1 13 31 08.2883506368 +30 30 32.960091564   17.51 17.25     ~ 4171 2

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2023.02.01-19:50:28

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