The blue-edge problem of the V1093 Her instability strip revisited using evolutionary models with atomic diffusion

Abstract

We have computed a new grid of evolutionary subdwarf B star (sdB) models from the start of central He burning, taking into account atomic diffusion due to radiative levitation, gravitational settling, concentration diffusion, and thermal diffusion. We have computed the non-adiabatic pulsation properties of the models and present the predicted p-mode and g-mode instability strips. In previous studies of the sdB instability strips, artificial abundance enhancements of Fe and Ni were introduced in the pulsation driving layers. In our models, the abundance enhancements of Fe and Ni occur naturally, eradicating the need to use artificial enhancements. We find that the abundance increases of Fe and Ni were previously underestimated and show that the instability strip predicted by our simulations solves the so-called blue edge problem of the subdwarf B star g-mode instability strip. The hottest known g-mode pulsator, KIC 10139564, now resides well within the instability strip {even when only modes with low spherical degrees (l<=2) are considered.

7 pages, 7 figures. Accepted for publication in Astronomy & Astrophysics

References in corpus (2)

• Gravity-mode pulsations in subdwarf B stars: a critical test of stellar opacity
• A seismic approach to testing different formation channels of subdwarf B stars

Cited by in corpus (9)

• Evolutionary modelling of subdwarf B stars using MESA with the predictive mixing and convective premixing schemes
• TESS first look at evolved compact pulsators : Discovery and asteroseismic probing of the g-mode hot B subdwarf pulsator EC 21494-7018
• Radial velocity variability and evolution of hot subdwarf stars
• The effects of near-core convective shells on the gravity modes of the subdwarf B pulsator KIC 10553698A
• Discovery of a second pulsating intermediate helium-enriched sdOB star
• Discovery of new TESS pulsating hot subdwarfs
• Pulsating subdwarf B stars observed with K2 during Campaign 7 and an examination of seismic group-properties
• The theoretical pulsation spectra of hot B subdwarfs. Static and evolutionary STELUM models
• Discerning internal conditions of pulsating hot subdwarf B stars. Modelling multiple trapped modes in KIC 10001893