Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Chaos in hydrodynamic BL Herculis models   We present non-linear, convective, BL Her-type hydrodynamic models that show
complex variability characteristic for deterministic chaos. The bifurcation
diagram reveals a rich structure, with many phenomena detected for the first
time in hydrodynamic models of pulsating stars. The phenomena include not only
period doubling cascades en route to chaos (detected in earlier studies) but
also periodic windows within chaotic band, type-I and type-III intermittent
behaviour, interior crisis bifurcation and others. Such phenomena are known in
many textbook chaotic systems, from the simplest discrete logistic map, to more
complex systems like Lorenz equations.
  We discuss the physical relevance of our models. Although except of period
doubling such phenomena were not detected in any BL Her star, chaotic
variability was claimed in several higher luminosity siblings of BL Her stars -
RV Tau variables, and also in longer-period, luminous irregular pulsators. Our
models may help to understand these poorly studied stars. Particularly
interesting are periodic windows which are intrinsic property of chaotic
systems and are not necessarily caused by resonances between pulsation modes,
as sometimes claimed in the literature.

10
The categories of this paper are: q-bio
25
The categories of this paper are: patt-sol
2
The categories of this paper are: math
14
The categories of this paper are: math-ph
4
The categories of this paper are: cond-mat
12
The categories of this paper are: nucl-th
24
The categories of this paper are: dg-ga
5
The categories of this paper are: gr-qc
17
The categories of this paper are: q-fin
0
The categories of this paper are: hep-ph
33
The categories of this paper are: plasm-ph
34
The categories of this paper are: chem-ph
37
The categories of this paper are: supr-con
20
The categories of this paper are: acc-phys
31
The categories of this paper are: ao-sci
13
The categories of this paper are: quant-ph