Department of Physics and Astronomy: Publications and Other Research
Date of this Version
1987
Document Type
Article
Citation
Bulletin of the American Astronomical Society, Vol. 19 (1987), p.762.
Abstract
We examine the light curves of 61 RRab stars from the data of Lub (1977). Fourier decomposition coefficients for 55 of these stars were reported by Simon and Teays (1982); the remaining light curves were Fourier decomposed in the present work. A plot of the Fourier quantities ϕ21 and ϕ31 vs. the metallicity parameter ΔS reveals a dichotomy among these stars. For the shorter-period group (37 stars), 0.374 ≤ P < 0.575, the Fourier phases ϕ21 and ϕ31 are directly correlated with metallicity. This is especially striking in the case of ϕ 21 which falls off very sharply with ΔS. The metallicity in the first group spans the range 0 ≤ ΔS ≤ 8. In the longer-period group, on the other hand, the correlation between the Fourier phases and ΔS virtually disappears. The latter group (20 stars) is characterized by: 0.575 ≤ P ≤ 0.747, 6 < ΔS ≤ 11. The remaining 4 stars stand out in one way or another as follows: AA Aq1 and S Ara belong to the first group but have ϕ21 and ϕ31 too small for their respective metallicities; UU Cet ahd FY Hya have periods which place them well within the second group, but nonetheless seem to follow the phase-metallicity correlation.
Comments
Copyright 1987 American Astronomical Society. Provided by the NASA Astrophysics Data System