Synchrotron emission from the T Tauri binary system V773 Tauri A

Autor(en)

M. Massi, J. Forbrich, K. M. Menten, G. Torricelli-Ciamponi, J. Neidhöfer, S. Leurini, F. Bertoldi

Abstrakt

The pre-main sequence binary system V773 Tau A shows

remarkable flaring activity around periastron passage. Here, we present

the observation of such a flare at a wavelength of 3 mm (90 GHz)

performed with the Plateau de Bure Interferometer. We examine different

possible causes for the energy losses responsible for the e-folding time

of 2.31 ± 0.19 h of that flare. We exclude synchrotron,

collisional, and inverse Compton losses because they are not consistent

with observational constraints, and we propose that the fading of the

emission is due to the leakage of electrons themselves at each

reflection between the two mirror points of the magnetic structure

partially trapping them. The magnetic structure compatible with both our

leakage model and previous observations is that of a helmet streamer

that, as in the solar case, can occur at the top of the X-ray-emitting,

stellar-sized coronal loops of one of the stars. The streamer may extend

up to ~20 R_* and interact with the corona of the other star

at periastron passage, causing recurring flares. The inferred magnetic

field strength at the two mirror points of the helmet streamer is in the

range 0.12-125 G, and the corresponding Lorentz factor, γ, of the

partially trapped electrons is in the range 20 < γ < 632. We

therefore rule out that the emission could be of gyro-synchrotron

nature: the derived high Lorentz factor proves that the nature of the

emission at 90 GHz from this pre-main binary system is synchrotron

radiation.

 

Organisation(en)

Institut für Astrophysik

Externe Organisation(en)

INAF - Osservatorio Astrofisico di Arcetri, Max-Planck-Institut für Radioastronomie, Rheinische Friedrich-Wilhelms-Universität Bonn

Journal

Astronomy & Astrophysics

Band

453

Seiten

959-964

ISSN

0004-6361

DOI

https://doi.org/10.1051/0004-6361:20053535

Publikationsdatum

07-2006

Peer-reviewed

Ja

ÖFOS 2012

103004 Astrophysik

Schlagwörter

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/a87a482c-9609-4fe8-9a36-a858ae60e4f0