On the systematics of asteroseismological mass determinations of PG1159 stars

TL;DR

This study evaluates different asteroseismological methods for determining the masses of PG1159 stars, highlighting the importance of method choice and showing that using mean period spacings yields more accurate results for certain stars.

Contribution

It compares the effectiveness of asymptotic versus average period spacings in asteroseismology for PG1159 stars using comprehensive evolutionary models.

Findings

Asteroseismology accurately determines stellar masses with high internal precision.

Using asymptotic period spacings overestimates masses for stars with short pulsation periods.

Mean period spacings reduce discrepancies between asteroseismological and spectroscopic masses.

Abstract

We analyze systematics in the asteroseismological mass determination methods in pulsating PG 1159 stars. We compare the seismic masses resulting from the comparison of the observed mean period spacings with the usually adopted asymptotic period spacings, and the average of the computed period spacings. Computations are based on full PG1159 evolutionary models with stellar masses ranging from 0.530 to 0.741 Mo that take into account the complete evolution of progenitor stars. We conclude that asteroseismology is a precise and powerful technique that determines the masses to a high internal accuracy, but it depends on the adopted mass determination method. In particular, we find that in the case of pulsating PG 1159 stars characterized by short pulsation periods, like PG 2131+066 and PG 0122+200, the employment of the asymptotic period spacings overestimates the stellar mass by about 0.06 Mo as compared with inferences from the average of the period spacings. In this case, the discrepancy between asteroseismological and spectroscopical masses is markedly reduced when use is made of the mean period spacing instead of the asymptotic period spacing.