The Nature of Strange Modes in Classical Variable Stars
| dc.creator | Buchler, J. R. | |
| dc.creator | Yecko, P. A. | |
| dc.creator | Kollath, Z. | |
| dc.date | 1997-07-07 | |
| dc.date | 1997-09-24 | |
| dc.date.accessioned | 2026-07-07T09:02:13Z | |
| dc.date.available | 2026-07-07T09:02:13Z | |
| dc.description | Strange modes have been found in the radial spectrum of many luminous stars, most recently in Cepheids and RR Lyrae. We show that there is nothing strange about these modes -- they must exist even in the adiabatic limit. With a change of variables and without approximation the adiabatic linear pulsation equation is reduced to a Schroedinger equation in which the radial coordinate is the local sound-traversal time. In this formulation, the narrow hydrogen partial ionization region is seen to act as a potential barrier, separating the star into two regions. Resonances between the two regions result in the strange modes, for which the ratio of interior to exterior amplitude is at a minimum. The relative location of the barrier changes with the stellar parameters, and this gives rise to avoided level-crossings along a sequence of models. 2 The appearance of strange modes and the associated level crossings are exhibited with an analytic toy-model with the potential barrier approximated by a delta function. This toy-model is readily extensible to nonadiabatic modes. Hydrodynamical calculations find that pure strange mode limit-cycles have extremely small photospheric velocities and luminosity variations in the milli-magnitude range. They are therefore expected to be difficult to observe. | |
| dc.description | 14 pages, including figures. Home Page http://www.phys.ufl.edu/~buchler Revised with minor corrections | |
| dc.identifier | https://arxiv.org/abs/astro-ph/9707081 | |
| dc.identifier | http://arxiv.org/abs/astro-ph/9707081 | |
| dc.identifier | A&A 326, 669 (1997) | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/148550 | |
| dc.subject | Astrophysics | |
| dc.subject | Chaotic Dynamics | |
| dc.title | The Nature of Strange Modes in Classical Variable Stars | |
| dc.type | text |