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arXiv · 1501.00863

Classifying the secondary component of the binary star W Aquilae

T. Danilovich·G. Olofsson·J. H. Black·K. Justtanont·H. Olofsson
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Abstract

AIMS: The object W Aql is an asymptotic giant branch (AGB) star with a faint companion. By determining more carefully the properties of the companion, we hope to better constrain the properties of the AGB star. METHODS: We present new spectral observations of the binary star W Aql at minimum and maximum brightness and new photometric observations of W Aql at minimum brightness. RESULTS: The composite spectrum near minimum light is predominantly from the companion at wavelengths $λ$ < 6000 $Å$. This spectrum can be classified as F8 to G0, and the brightness of the companion is that of a dwarf star. Therefore, it can be concluded that the companion is a main sequence star. From this, we are able to constrain the mass of the AGB component to 1.04 - 3 $M_\odot$ and the mass of the W Aql system to 2.1 - 4.1 $M_\odot$ . Our photometric results are broadly consistent with this classification and suggest that the main sequence component suffers from approximately 2 mag of extinction in the V band primarily due to the dust surrounding the AGB component.

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T. Danilovich, G. Olofsson, J. H. Black, K. Justtanont, H. Olofsson. 2015-01-05. Classifying the secondary component of the binary star W Aquilae. https://doi.org/10.1051/0004-6361%2F201423672

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