The symbiotic star H1-36

A composite model of line and continuum spectra from radio to ultraviolet

¹ Dipartimento di Astronomia, Università di Padova, Vicolo dell'Osservatorio 2, 35122 Padova, Italy e-mail: [rodolfo.angeloni;stefano.ciroi;piero.rafanelli]@unipd.it
² School of Physics and Astronomy, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978, Israel e-mail: contini@post.tau.ac.il

Received: 22 March 2007
Accepted: 2 May 2007

Abstract

Aims.In this paper, we analyse the spectra of D-type SS H1-36 within a colliding-wind scenario. We aim to analyse the properties of this object by taking the observational data along the whole electromagnetic spectrum into account, in order to derive a self-consistent picture able to interpret the nature of the system as a whole.

Methods.After constraining the relative physical conditions by modelling more than 40 emission lines from radio to UV, we are able to explain the continuum spectral energy distribution by considering all the emitting contributions arising from both the stars, the dust shells, and the gaseous nebulæ.

Results.A comprehensive model of the radio spectra allows reproduction of the different slopes of the radio profile and the turnover frequency, as well as the different sizes of the observed shocked envelope at different frequencies in the light of the contributions from the expanding and reverse nebulæ. The IR continuum unveils the presence of two dust shells with different radii and temperatures, which might be a distinctive feature of D-type symbiotic systems as a class of objects. The broad profiles of IR lines direct us to investigate whether an X-ray jet may be present.

Conclusions.This insight leads us to indicate H1-36 as a promising X-ray target and to encourage observations and studies that consistently take the complex nature of symbiotic stars into account throughout the whole electromagnetic spectrum.