Mechanical Equilibrium of Hot, Large-Scale Magnetic Loops on T Tauri Stars

TL;DR

This paper investigates how hot, large-scale magnetic loops on T Tauri stars can reach great heights by considering the effects of stellar winds, challenging previous models that predicted such loops could not attain these heights.

Contribution

The study introduces a model including stellar wind effects, demonstrating that hot, negatively buoyant loops can achieve mechanical equilibrium at large stellar radii.

Findings

Hot loops can reach heights beyond the closed corona due to stellar wind effects.

Negatively buoyant hot plasma can be supported at large heights in equilibrium.

Models align with observations of extended magnetic structures on T Tauri stars.

Abstract

The most extended, closed magnetic loops inferred on T Tauri stars confine hot, X-ray emitting plasma at distances from the stellar surface beyond the the X-ray bright corona and closed large-scale field, distances comparable to the corotation radius. Mechanical equilibrium models have shown that dense condensations, or "slingshot prominences", can rise to great heights due to their density and temperatures cooler than their environs. On T Tauri stars, however, we detect plasma at temperatures hotter than the ambient coronal temperature. By previous model results, these loops should not reach the inferred heights of tens of stellar radii where they likely no longer have the support of the external field against magnetic tension. In this work, we consider the effects of a stellar wind and show that indeed, hot loops that are negatively buoyant can attain a mechanical equilibrium at heights above the typical extent of the closed corona and the corotation radius.