THE EFFECT OF OPACITY ON THEORETICAL MODELS OF RR LYRAE STARS.
Item
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Title
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THE EFFECT OF OPACITY ON THEORETICAL MODELS OF RR LYRAE STARS.
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Identifier
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AAI8312353
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identifier
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8312353
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Creator
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HUBICKYJ, E. OLENKA.
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Contributor
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Prof. Richard Stothers
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Date
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1983
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Language
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English
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Publisher
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City University of New York.
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Subject
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Physics, Astronomy and Astrophysics
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Abstract
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The RR Lyrae instability strip is investigated with computer models that were calculated using Carson opacities. A nonlinear computer program was applied to fundamental and first overtone modes of pulsation (ab- and c-type, respectively). Comparison of the models with observed surface light and velocity curves showed good agreement in phase of the secondary bump on the velocity curve ((phi)(,(nu)) (TURN)1.6) and light amplitude for M/M(,*) = 0.60 - 0.65 log (L/L(,*)) (TURN) 1.7 and Y = 0.25. A linear computer program was used to examine the location of the blue edges of the instability strip as mass and chemical composition varied. The results of the linear survey showed: (1) no substantial change in the PTLM relation due to opacity; (2) similar blue edges to those in previous studies that employed the Los Alamos opacity series are calculated with the Carson models for a lower helium abundance and with masses more consistent with evolutionary tracks. Several comparison tests of the models with observations showed good agreement. The overall linear results indicated a mass of 0.70 (+OR-) 0.05 M(,*) and a helium content of 0.25 (+OR-) 0.04.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
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Program
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Physics
