Aims. We study the effects of moderate deviations from solar abundances upon the atmospheric structure and colours of typical Mira variables. Methods. We present two model series of dynamical opacity-sampling models of Mira variables which have (1) 1/3 solar metallicity; and (2) "mild" S-type C/O abundance ratio ([C/O] = 0.9) with typical Zr enhancement (solar +1.0). These series are compared to a previously studied solar-abundance series which has similar fundamental parameters (mass, luminosity, period, radius) that are close to those of o Cet. Results. Both series show noticeable effects of abundance upon stratifications and infrared colours but cycle-to-cycle differences mask these effects at most pulsation phases, with the exception of a narrow-water-filter colour near minimum phase.
Bibliographical noteCopyright ESO 2014. First published in Astronomy and astrophysics 565, A119, 2014, published by EDP Sciences. The original publication is available at http://doi.org/10.1051/0004-6361/201323183
- stars: AGB and post-AGB
- stars: atmospheres
- stars: abundances