The first direct spectroscopic detection of a white dwarf primary in an AM CVn system
UNSPECIFIED. (2005) The first direct spectroscopic detection of a white dwarf primary in an AM CVn system. ASTROPHYSICAL JOURNAL, 636 (2 Part 2). L125-L128. ISSN 0004-637XFull text not available from this repository.
We report the results of a synthetic spectral analysis of HST STIS spectra of the AM CVn - type cataclysmic variable CP Eri obtained when the system was in quiescence. The FUV spectrum is best fitted by a helium-dominated, hybrid composition ( DBAZ) white dwarf with T-eff similar to 17,000 +/- 1000 K, log g similar to 8, He/H ambundance ratio by number similar to 1000, metallicity Z similar to 0.05 x solar, and V sin i similar to 400 +/- 100 km s(-1). This is the first directly detected primary white dwarf in any AM CVn system, and the surface abundance and rotation rate for the white dwarf primary are the first to be reported for AM CVn systems. The model- predicted distance is similar to 1000 pc. The spectral fits using pure He photospheres or He- rich accretion disks were significantly less successful. Based on the analysis of our FUV spectra, CP Eri appears to contain a hybrid composition DBAZ white dwarf with a metallicity that sets it apart from the other two AM CVn stars that have been observed in quiescence and are metal- poor. The implications of this analysis for evolutionary channels leading to AM CVn systems are discussed.
|Item Type:||Journal Article|
|Subjects:||Q Science > QB Astronomy|
|Journal or Publication Title:||ASTROPHYSICAL JOURNAL|
|Publisher:||UNIV CHICAGO PRESS|
|Official Date:||10 January 2005|
|Number:||2 Part 2|
|Number of Pages:||4|
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