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Spectroscopic evidence for the binary nature of AM CVn

G. Nelemans·D. Steeghs·P. J. Groot
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Abstract

We analysed archival spectroscopic data of AM CVn taken with the William Herschel Telescope in 1996. In the literature two orbital periods for AM CVn are proposed. A clear S-wave in the HeI 4471, 4387 and 4143 Ålines is revealed when the spectra are folded on the 1029 s period. No signature of this S-wave is seen when folded on 1051 s. Doppler tomography of the line profiles shows a clear signature of the hotspot. Using this we can constrain the value of K_2 to lie between 210 and 280 km/s. Our work confirms the binary nature of AM CVn beyond any doubt, establishes 1028.73 s as the true orbital period and supports the interpretation of AM CVn as a permanent superhump system.

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G. Nelemans, D. Steeghs, P. J. Groot. 2001-04-12. Spectroscopic evidence for the binary nature of AM CVn. https://doi.org/10.1046/j.1365-8711.2001.04614.x

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