We have gathered and analyzed 1493 high-quality multicolor Geneva photometric data taken over 21 years of the B3Vstar HD 129929. We detect six frequencies, among which appear the effects of rotational splitting with a spacing of ∼0.0121 cycles per day, which implies that the star rotates very slowly. A nonadiabatic analysis of the oscillations allows us to constrain the metallicity of the star to
Z
ϵ [0.017,0.022], which agrees with a similar range derived from spectroscopic data. We provide evidence for the occurrence of core convective overshooting in the star, with α
ov
= 0.10 ± 0.05, and we rule out rigid rotation.
Abstract. We calculate time sequences of Si III 455.26 nm line profiles for 10 M models using results of the linear nonadiabatic calculations of Dziembowski & Pamyatnykh (1993) for oscillations of β Cephei stars. The spectroscopic observables are amplitude ratios and phase differences for various oscillating parameters derived from line profiles. We search theoretical diagrams involving these observables for unstable modes with low harmonic degrees ( = 0, 1 and 2) and azimuthal orders of m = − , . . . , + . We show that all unstable modes are grouped in domains assigned by different and m-values. In almost all studied diagrams, the retrograde (m > 0), prograde (m < 0) and zonal (m = 0) modes are well separated from each other. The clearest separation of the domains occurs for the m-values in the diagram making use of the first and second moments of line profiles. Neither the inclination angle i or the amplitude of the stellar radius variation change this conclusion. The diagram is however sensitive to the equatorial velocity ve of the star. The method of determination of m is valid and efficient for the equatorial rotational velocity 20 < ve < 50 km s −1 . The observables studied here are usually by-products of periodogram analyses of time series of observed characteristics of line profiles. Our results point to the significance of such data for asteroseismology in addition to measurements of oscillation frequencies and photometric nonadiabatic observables.
We present a new method of mode identification based on the line profile variations. We calculate time series of Si III 455.26 nm for models of β Cep stars with a mass of 10 M⊙. The Spectroscopic observables are amplitude ratio and phase difference for various oscillation parameters derived from the line profile changes. Based on the computed values we plot diagrams to search for the best discriminators of modes.In most Spectroscopic diagrams the unstable modes are grouped in well-defined regions with different m-values, and a few of them give also separation with respect to l-values. Moreover, on the basis of almost all of the diagrams we can distinguish the prograde modes from the retrograde ones, and the zonal modes from those with m ≠ 0.In this paper we discuss also the influence of the inclination angle, the amplitude of the radius variation and the equatorial velocity on the diagnostic values of the Spectroscopic diagrams.
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