H$\alpha$ spectral monitoring of epsilon Aurigae 2009-2011 eclipse

TL;DR

This study presents extensive high-resolution Hα spectral data of epsilon Aurigae during its 2009-2011 eclipse, revealing complex system dynamics and refining eclipse duration estimates, with implications for ongoing monitoring.

Contribution

The paper provides a comprehensive dataset of Hα spectra during the eclipse, offering new insights into the system's complexity and challenging previous eclipse duration estimates.

Findings

Eclipse duration was underestimated in previous studies.

The Hα line shows complex dynamical behavior during eclipse.

Key dates of eclipse phases were redefined based on spectral data.

Abstract

We present and analyze epsilon Aurigae data concerning the evolution of the H$\alpha$ line on the occasion of the 2009 International observation campaign launched to cover the eclipse of this object. About 250 high resolution spectra of the H$\alpha$ line were obtained by amateur covering the three years around eclipse. We visually inspect the dynamical spectrum constructed from the data and analyze the evolution with time of the radial velocity and of EW (Equivalent Width) vs V mag. The spectroscopic data reveal many details which confirm the complexity of the Aurigae system. The object is far from being understood. In particular, according to our measurements, the eclipse duration has been underestimated and key dates were defined. A complete analysis of details revealed by our data would require much time and effort. Observers are encouraged to continue monitoring the H$\alpha$ line out of eclipse in the hope that it will provide further important information.