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Astron. Astrophys. 344, 607-613 (1999)
The eclipse of the symbiotic star SY Muscae *
C.B. Pereira,
V.G. Ortega and
I. Monte-Lima
Observatório Nacional, Departamento de Astronomia Galáctica e Extra-Galáctica, Rua Gen. José Cristino, 77, São Cristóvão, CEP 20921-400, Rio de Janeiro, Brazil
Received 21 August 1998 / Accepted 11 January 1999
Abstract
We present ultra-violet observations of the symbiotic star
SY Mus obtained with IUE in 1996. The observations were timed to
cover ingress and egress. We observe phase dependent intensity
variations of the continuum and of the emission lines. These
variations are caused by a wavelength dependent opacity with the
characteristics of Rayleigh scattering plus a wavelength independent
attenuation. From the Rayleigh scattering opacity we derive the column
densities of neutral hydrogen as a function of orbital phase. We then
apply inversion methods to investigate the giant's cool wind velocity
profile. A new convenient analytical expression for this profile is
presented and compared to other laws. The modeling of the giant's cool
wind and the assumption of a terminal velocity of
30 km s-1, leads to a mass loss rate of
![[FORMULA]](img1.gif)
![[FORMULA]](img2.gif)
yr-1
for SY Mus.
Key words: stars: binaries:
eclipsing 
stars: binaries:
symbiotic
stars: individual:
SY Mus
stars: mass-loss
* Based on observations by the International Ultraviolet Explorer taken at VILSPA.
Send offprint requests to: C.B. Pereira
Contents
- 1. Introduction
- 2. Observations
- 2.1. Continuum fluxes
- 2.2. Emission lines
- 3. The eclipse
- 4. The wind structure of SY Mus
- 5. Conclusions
- Acknowledgements
- References
© European Southern Observatory (ESO) 1999
Online publication: March 18, 1999
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