2001/10/31 by J. Robert Buchler, J. R. Buchler, Z. Kolláth +1 · 1 citation
Physics and Astronomy · #Amplitude #Astro and Planetary Science #Astrophysics #Astrophysics and Star Formation Studies #Bifurcation #Cepheid variable #Globular cluster #Instability #Instability strip #Mechanics #Mode (computer interface) #Nonlinear system #Optics #Physics #RR Lyrae variable #Stars #Stellar pulsation #Stellar, planetary, and galactic studies #astro-ph #nlin.SI #physics.flu-dyn
paper · pdf · doi:10.1086/340550
5 pages, 3 figures, ApJ (in press)
arxiv created 2002/04/15 · openalex publication_date 2002/07/01 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Near the edges of the instability strip,the rate of stellar evolution is larger than the growth rate of the pulsation amplitude, and the same holds whenever the star is engaged in pulsational mode switching. Stellar evolution therefore controls the onset of pulsation at the edges of the instability strip and of mode switching inside it. Two types of switchings (bifurcations) occur. In a soft bifurcation, the switching timescale is the inverse harmonic mean of the pulsational modal growth rate and of the stellar evolution rate. In a hard bifurcation, the switching times can be substantially longer than the thermal timescale, which is typically of the order of 100 periods for Cepheids and RR Lyrae stars. We discuss some of the observational consequences, in particular the paucity of low-amplitude pulsators at the edges of the instability strip.