Does the Scaling Relation Depend on Metallicity? Insights from 3D Convection Simulations

Abstract

Solar-like oscillations have been detected in thousands of stars thanks to modern space missions. These oscillations have been used to measure stellar masses and ages, which have been widely applied in Galactic archeology. One of the pillars of such applications is the ${\nu }_{\max }$ scaling relation: the frequency of maximum power ${\nu }_{\max }$ , assumed to be proportional to the acoustic cutoff frequency, ν _ac , scales with effective temperature and surface gravity. However, the theoretical basis of the ${\nu }_{\max }$ scaling relation is uncertain, and there is an ongoing debate about whether it can be applied to metal-poor stars. We investigate the metallicity dependence of the ${\nu }_{\max }$ scaling relation by carrying out 3D near-surface convection simulations for solar-type stars with [Fe/H] between −3 and 0.5 dex. First, we found a negative correlation between ν _ac and metallicity from the 3D models. This is in tension with the positive correlation identified by studies using 1D models. Second, we estimated theoretical ${\nu }_{\max }$ values using velocity amplitudes determined from first principles, by quantifying the mode excitation and damping rates with methods validated in our previous works. We found that ${\nu }_{\max }$ does not show correlation with metallicity at solar effective temperature and surface gravity. This study opens an exciting prospect of testing the asteroseismic scaling relations against realistic 3D hydrodynamical stellar models.

Keywords

• Stellar oscillations
• Pulsation modes
• Radiative magnetohydrodynamics
• Stellar convection envelopes
• Stellar atmospheres