Hans Martin Schmid
ETH Zurich, Switzerland
System properties of the eccentric symbiotic binary BX Mon, based on ARAS spectroscopy and AAVSO photometry
Abstract:
(a collaboration with: F. Sims, S. Curry, C. Eldridge, J. Foote,
J. Guarro Flo, P. Luckas, J.R. Foster, and F. Teyssier)
BX Mon is a symbiotic binary consisting of a M5 III red giant and
a white dwarf undergoing nova-like activity. The system is outstanding,
because it has for its orbital period of about 1300 days a very
high eccentricity of e=0.5, much higher than other symbiotic stars
with similar periods. BX Mon went around 2010 into outburst,
and shows now a bright spectrum of an extended F-type star.
Therefore, it can be used as double lined spectroscopic binary
with well defined eclipses allowing a very detailed system analysis.
We use archival echelle spectra from the Astronomical Ring for
Amateur Spectroscopy (ARAS). which allow the determination of the
radial velocity curves with a precision of about +/-2 km/s for the
hot and cool component in BX Mon. The combination with the well
sampled eclipse light curve from the AAVSO (Astronomical Association of
Variable Star Observers) yields accurate orbital and stellar parameters.
Such ideal observational properties for detailed system characterizations
are very rare for symbiotic binaries. In addition, BX Mon is because of
its extreme eccentricity a very interesting object for the investigation
of mass transfer processes and the evolution of red giant binaries.