EDP Sciences
Free access
Volume 391, Number 2, August IV 2002
Page(s) 609 - 615
Section Formation, structure and evolution of stars
DOI http://dx.doi.org/10.1051/0004-6361:20020878

A&A 391, 609-615 (2002)
DOI: 10.1051/0004-6361:20020878

The origin of the radio emission from $\beta$ Lyrae

G. Umana1, F. Leone2 and C. Trigilio1

1  Istituto di Radioastronomia del C.N.R., Stazione VLBI di Noto, C.P. 161 Noto, Italy
2  INAF, Osservatorio Astrofisico di Catania, via S. Sofia 78, 95123 Catania, Italy

(Received 5 October 2001 / Accepted 15 May 2002 )

In this paper we present new observational evidence that supports the presence of an extra source of continuum emission in the binary system $\beta$ Lyrae . New VLA and IRAM observations, together with published data from the literature and ISO archive data, allow us to build the Spectral Energy Distribution of the binary between $5\times 10^{9}$ Hz and $5\times 10^{15}$ Hz. The radio-millimeter part of the spectrum is consistent with free-free emission from a symbiotic-like wind associated with the primary component and ionized by the radiation field of the hidden companion. Furthermore, we also consider the possibility that the observed radio flux originates from collimated radio structures associated with the mass gaining component and its disk (Conical thermal jets). An extrapolation of this emission to the far-IR part of the spectrum indicates that in both cases the free-free contribution at these frequencies cannot explain the observations and that the observed infrared excess flux is due principally to the secondary component and its associated disk.

Key words: stars: binaries: eclipsing -- stars: individual: $\beta$ Lyrae -- radio continuum: stars

Offprint request: G. Umana, umana@ira.noto.cnr.it

© ESO 2002