A Physical Interpretation of Recent Period-Luminosity Relations for RR Lyrae Variables.

Abstract

view Abstract Citations (19) References (12) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS A Physical Interpretation of Recent Period-Luminosity Relations for RR Lyrae Variables. Cox, J. P. ; Castor, J. I. ; King, D. S. Abstract A simple physical interpretation is proposed of the period-luminosity (ll-L) relation for RR Lyrae variables which was found by Iben and Huchra on the basis of linearized pulsation calculations. Essentially, the intersection on the diagram of the fundamental and first-harmonic blue instability edges, on which this ll-L relation is based, is caused by a "quenching" of the first harmonic. This quenching results from the proximity of the driving region, assumed here to be the region of He+ ionization, to the node. The critical separation between this region and tile node required to cause the quenching is governed primarily by the mass/radius ratio. The interpretation leads to a "theoretical" lI-L relation in good agreement with their ll-L relation. The relationship of the Iben-Huchra ll-L relation to one obtained earlier by Christy from nonlinear calculations is discussed. It is suggested that the former is, in principle, essentially a subset of the latter. The near identity of their slopes, noted by Iben and lluchra, is shown to be a consequence of the fact that the Christy H-L relation is independent of mass. The lack of a dependence of the Christy H-L relation on composition leads to a contradiction between Iben and Huchra's results and Christy's resbfts if the two ll-L relations are related as we have suggested. The need for further nonlinear pulsation calculations is emphasized. Publication: The Astrophysical Journal Pub Date: March 1972 DOI: 10.1086/151362 Bibcode: 1972ApJ...172..423C full text sources ADS |