Evidence for Centrifugal Breakout around the Young M Dwarf TIC 234284556

TL;DR

This study presents evidence supporting the occurrence of centrifugal breakout in a young M dwarf star, using multi-instrument data to analyze transient magnetospheric phenomena and their implications for stellar mass loss.

Contribution

It provides the first empirical evidence of centrifugal breakout in a young star, linking magnetospheric clouds with mass-loss mechanisms and broadening understanding of stellar magnetic activity.

Findings

Detection of a sudden disappearance of a stable transit event.

Observation of an anomalous brightening prior to the event.

Estimation of gas and dust mass involved in the breakout.

Abstract

Magnetospheric clouds have been proposed as explanations for depth-varying dips in the phased light curves of young, magnetically active stars such as $\sigma$ Ori E and RIK-210. However, the stellar theory that first predicted magnetospheric clouds also anticipated an associated mass-loss mechanism known as centrifugal breakout for which there has been limited empirical evidence. In this paper, we present data from TESS, LCO, ASAS-SN, and Veloce on the 45 Myr M3.5 star TIC 234284556, and propose that it is a candidate for the direct detection of centrifugal breakout. In assessing this hypothesis, we examine the sudden ($\sim$1-day timescale) disappearance of a previously stable ($\sim$1-month timescale) transit-like event. We also interpret the presence of an anomalous brightening event that precedes the disappearance of the signal, analyze rotational amplitudes and optical flaring as a proxy for magnetic activity, and estimate the mass of gas and dust present immediately prior to the potential breakout event. After demonstrating that our spectral and photometric data support a magnetospheric clouds and centrifugal breakout model and disfavor alternate scenarios, we discuss the possibility of a coronal mass ejection (CME) or stellar wind origin of the corotating material and we introduce a reionization mechanism as a potential explanation for more gradual variations in eclipse parameters. Finally, after comparing TIC 234284556 with previously identified "flux-dip" stars, we argue that TIC 234284556 may be an archetypal representative of a whole class of young, magnetically active stars.