A new method for determining physical parameters of fundamental mode RR Lyrae stars from multicolour light curves

Abstract

We present a new method for determining physical parameters of RRab variables exclusively from multicolour light curves. Our method is an Inverse Photometric Baade-Wesselink analysis which, using a nonlinear least squares algorithm, searches for the effective temperature (T_eff) and pulsational velocity (V_p) curves and other physical parameters that best fit the observed light curves, utilising synthetic colours and bolometric corrections from static atmosphere models. The T_eff and V_p curves are initially derived from empirical relations then they are varied by the fitting algorithm. The method yields the variations and the absolute values of the radius, the effective temperature, the visual brightness, and the luminosity of individual objects. Distance and mass are also determined. The method is tested on 9 RRab stars subjected to Baade-Wesselink analyses earlier by several authors. The physical parameters derived by our method using only the light curve data of these stars are well within their possible ranges defined by direct Baade-Wesselink and other techniques. A new empirical relation between the I_C magnitude and the pulsational velocity is also presented, which allows to construct the V_p curve of an RRab star purely from photometric observations to an accuracy of about 3.5 km/s.

12 pages, 10 figures, 4 tables. Accepted for publication in MNRAS

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Cited by in corpus (15)

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• Blazhko RR Lyrae light curves as modulated signals
• Revisiting CoRoT RR Lyrae stars: detection of period doubling and temporal variation of additional frequencies
• The Kinematic Properties of BHB and RR Lyrae stars towards the Anticentre and the North Galactic Pole: The Transition between the Inner and the Outer Halo
• Overtone and multi-mode RR Lyrae stars in the globular cluster M3
• The Multi-periodic Blazhko Modulation of CZ Lacertae
• An extensive photometric study of the Blazhko RR Lyrae star DM Cyg
• Can turbulent convective variations drive the Blazhko cycle? Dynamical investigation of the Stothers idea
• An extensive photometric study of the Blazhko RR Lyrae star RZ Lyr
• The light-curve modulation of XY And and UZ Vir - Two Blazhko RR Lyrae stars with additional frequencies
• A cautionary tale of interpreting O-C diagrams: period instability in a classical RR Lyr Star Z CVn mimicking as a distant companion
• Extensive study of HD 25558, a long-period double-lined binary with two SPB components
• Blazhko type fundamental-mode RR Lyrae stars in the globular cluster, M3
• A Far-UV Variability Survey of the Globular Cluster M80
• Hysteresis of atmospheric parameters of 12 RR Lyrae stars based on multichannel simultaneous Stroemgren photometry