On the nature of the cool component of MWC 560^*

¹ N. Copernicus Astronomical Center, Bartycka 18, 00-716 Warsaw, Poland e-mail: marg@camk.edu.pl
² South African Astronomical Observatory, PO Box 9, Observatory, 7935, South Africa
³ National Astrophysics and Space Science Programme, Department of Mathematics and Applied Mathematics, and the Department of Astronomy, University of Cape Town, South Africa

Received: 10 October 2006
Accepted: 19 November 2006

Abstract

Context.MWC 560 (V694 Mon) is one of the most enigmatic symbiotic system with a very active accretion-powered hot component. Such activity can be supported only by a luminous asymptotic giant branch star, i.e. a Mira or SR variable, with a high mass-loss rate. It is also a very unusual jet source because the jet axis lies practically parallel to the line of sight.

Aims.The aims of our study are the determination of the evolutionary status of the cool component of MWC 560.

Methods.Our methods involve analysis of near-IR JHKL and optical light curves.

Results.The cool component of MWC 560 pulsates with a period of ~340 days, and it is probably a red SR variable on the thermally pulsing AGB. The high mass-loss rate expected for such a star is sufficient to power the observed activity of the hot companion.