A Search For X-ray Emission From Colliding Magnetospheres In Young Eccentric Stellar Binaries

TL;DR

This study investigates whether colliding magnetospheres in young eccentric binary stars lead to increased X-ray emission, using Chandra observations of four systems, and finds tentative evidence of flux enhancement near periastron.

Contribution

It provides the first systematic X-ray observational analysis of multiple young eccentric binaries to assess magnetosphere collision effects.

Findings

X-ray flux tends to increase near periastron in the sample

The observed flux increase is statistically tentative (~2.5 sigma)

Current data cannot definitively attribute X-ray enhancements to magnetosphere collisions

Abstract

Among young binary stars whose magnetospheres are expected to collide, only two systems have been observed near periastron in the X-ray band: the low-mass DQ Tau and the older and more massive HD 152404. Both exhibit elevated levels of X-ray emission at periastron. Our goal is to determine whether colliding magnetospheres in young high-eccentricity binaries commonly produce elevated average levels of X-ray activity. This work is based on Chandra snapshots of multiple periastron and non-periastron passages in four nearby young eccentric binaries (Parenago 523, RX J1622.7-2325 Nw, UZ Tau E, and HD 152404). We find that for the merged sample of all 4 binaries the current X-ray data show an increasing average X-ray flux near periastron (at about 2.5-sigma level). Further comparison of these data with the X-ray properties of hundreds of young stars in the Orion Nebula Cluster, produced by the Chandra Orion Ultradeep Project (COUP), indicates that the X-ray emission from the merged sample of our binaries can not be explained within the framework of the COUP-like X-ray activity. However, due to the inhomogeneities of the merged binary sample and the relatively low statistical significance of the detected flux increase, these findings are regarded as tentative only. More data are needed to prove that the flux increase is real and is related to the processes of colliding magnetospheres.