121 research outputs found
New Insight into the FS CMa System MWC 645 from Near-Infrared and Optical Spectroscopy
The B[e] phenomenon is manifested by a heterogeneous group of stars
surrounded by gaseous and dusty circumstellar envelopes with similar physical
conditions. Among these stars, the FS CMa-type objects are suspected to be
binary systems, which could be experiencing or have undergone a mass-transfer
process that could explain the large amount of material surrounding them. We
aim to contribute to the knowledge of a recently confirmed binary, MWC 645,
which could be undergoing an active mass-transfer process. We present
near-infrared and optical spectra, identify atomic and molecular spectral
features, and derive different quantitative properties of line profiles. Based
on publicly available photometric data, we search for periodicity in the light
curve and model the spectral energy distribution. We have detected molecular
bands of CO in absorption at 1.62 m and 2.3 m for the first time. We
derive an upper limit for the effective temperature of the cool binary
component. We found a correlation between the enhancement of the H
emission and the decrease in optical brightness that could be associated with
mass-ejection events or an increase in mass loss. We outline the global
properties of the envelope, possibly responsible for brightness variations due
to a variable extinction, and briefly speculate on different possible
scenarios.Comment: 20 pages, 11 figures, 2 tables, published in Galaxie
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