Multi-line Doppler imaging of MR Ser in high-state

TL;DR

This study presents multi-line Doppler imaging and photometry of the polar MR Ser in a high accretion state, revealing the ionization structure and emission regions within the accretion flow.

Contribution

It provides detailed Doppler tomograms across multiple lines and constrains the ionization structure and emission mechanisms in MR Ser during high state.

Findings

Emission from accretion flow and heated companion surface identified

Highest ionization region near magnetospheric radius located

Balmer and Helium emissions explained by soft X-ray illumination

Abstract

Doppler images in Balmer, HeI, HeII and CII lines, and simultaneous I-band photometry of the polar MR Ser are presented and analyzed. The Balmer and Helium Doppler tomograms of this bright polar at high mass transfer state show the emission from the accretion flow and the heated surface of the companion star. As a result of a comparison between the Doppler tomograms the ionization structure of the flow could be constrained. The highest ionization region was found in the vicinity of the magnetospheric radius. Photoionization modeling of the accretion column indicates that the Balmer and Helium emission line production in this system can be explained by the central soft Xray illumination only. The orbital ephemeris of MR Ser has been revised.