Article (Scientific journals)
Discovery of a New AM CVn System with the Kepler Satellite
Fontaine, Gilles; Brassard, Pierre; Green, E. M. et al.
2011In Astrophysical Journal, 726, p. 92
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Keywords :
accretion; accretion disks; binaries: close; stars: individual: SDSS J190817.07+394036.4 KIC 004547333; white dwarfs
Abstract :
[en] We report the discovery of a new AM CVn system on the basis of broadband photometry obtained with the Kepler satellite supplemented by ground-based optical spectroscopy. Initially retained on Kepler target lists as a potential compact pulsator, the blue object SDSS J190817.07+394036.4 (KIC 004547333) has turned out to be a high-state AM CVn star showing the He-dominated spectrum of its accretion disk significantly reddened by interstellar absorption. We constructed new grids of NLTE synthetic spectra for accretion disks in order to analyze our spectroscopic observations. From this analysis, we infer preliminary estimates of the rate of mass transfer, the inclination angle of the disk, and the distance to the system. The AM CVn nature of the system is also evident in the Kepler light curve, from which we extracted 11 secure periodicities. The luminosity variations are dominated by a basic periodicity of 938.507 s, likely to correspond to a superhump modulation. The light curve folded on the period of 938.507 s exhibits a pulse shape that is very similar to the superhump wavefront seen in AM CVn itself, which is a high-state system and the prototype of the class. Our Fourier analysis also suggests the likely presence of a quasi-periodic oscillation similar to those already observed in some high-state AM CVn systems. Furthermore, some very low-frequency, low-amplitude aperiodic photometric activity is likely present, which is in line with what is expected in accreting binary systems. Inspired by previous work, we further looked for and found some intriguing numerical relationships between the 11 secure detected frequencies, in the sense that we can account for all of them in terms of only three basic clocks. This is further evidence in favor of the AM CVn nature of the system.
Disciplines :
Space science, astronomy & astrophysics
Author, co-author :
Fontaine, Gilles
Brassard, Pierre
Green, E. M.
Charpinet, Stéphane
Dufour, P.
Hubeny, I.
Steeghs, D.
Aerts, C.
Randall, S. K.
Bergeron, P.
Guvenen, B.
O'Malley, C. J.
Van Grootel, Valérie  ;  Laboratoire d'Astrophysique de Toulouse-Tarbes
Ostensen, R. H.
Bloemen, S.
Silvotti, R.
Howell, S. B.
Baran, A.
Kepler, S. O.
Marsh, T. R.
Montgomery, M. H.
Oreiro, R.
Provencal, J.
Telting, J. H.
Winget, D. E.
Zima, W.
Christensen-Dalsgaard, J.
Kjeldsen, H.
More authors (18 more) Less
Language :
English
Title :
Discovery of a New AM CVn System with the Kepler Satellite
Publication date :
January 2011
Journal title :
Astrophysical Journal
ISSN :
0004-637X
eISSN :
1538-4357
Publisher :
University of Chicago Press, Chicago, United States - Illinois
Volume :
726
Pages :
92
Peer reviewed :
Peer Reviewed verified by ORBi
Available on ORBi :
since 22 January 2012

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