On the anomaly of Balmer line profiles of A-type stars. Fundamental binary systems

TL;DR

This study investigates the Balmer line profile anomaly in A-type stars by analyzing binary systems with known fundamental parameters, finding that previous discrepancies in effective temperature measurements are resolved.

Contribution

It provides a revised set of fundamental parameters for binary systems and demonstrates that the previously observed Teff discrepancy is no longer evident in recent data.

Findings

Discrepancy in Teff for 7000K < Teff < 9000K is resolved.

Balmer line profiles now agree with fundamental and photometric values.

Revised fundamental parameters improve consistency in stellar temperature measurements.

Abstract

In previous work, Gardiner et al. (1999) found evidence for a discrepancy between the Teff obtained from Balmer lines with that from photometry and fundamental values for A-type stars. An investigation into this anomaly is presented using Balmer line profiles of stars in binary system with fundamental values of both Teff and log g. A revision of the fundamental parameters for binary systems given by Smalley & Dworetsky (1995) is also presented. The Teff obtained by fitting Halpha and Hbeta line profiles is compared to the fundamental values and those obtained from uvby photometry. We find that the discrepancy found by Gardiner et al. (1999) for stars in the range 7000 K < Teff < 9000 K is no longer evident.