Open AccessSpectroscopic evidence for the binary nature of AM CVn
Author(s) -
Nelemans G.,
Steeghs D.,
Groot P.J.
Publication year - 2001
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.2001.04614.x
Subject(s) - physics , binary number , astrophysics , spectral line , astronomy , doppler effect , orbital period , emission spectrum , telescope , interpretation (philosophy) , signature (topology) , line (geometry) , stars , geometry , arithmetic , mathematics , computer science , programming language
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 He i 4471, 4387 and 4143 Å lines 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 −1 . 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.