A Multi-wavelength, Multi-epoch Monitoring Campaign of Accretion Variability in T Tauri Stars from the ODYSSEUS Survey. II. Photometric Light Curves

TL;DR

This study presents a multi-wavelength, multi-epoch photometric monitoring of four T Tauri stars, revealing significant variability linked to accretion processes and stellar rotation, highlighting the complexity of using photometry as an accretion indicator.

Contribution

It provides new insights into the variability patterns of CTTSs through simultaneous multi-wavelength observations, emphasizing the nuanced relationship between accretion and photometric changes.

Findings

All targets show significant variability on days to years.

Variability often linked to stellar rotation and stochastic accretion.

Photometric accretion indicators vary with target and epoch.

Abstract

Classical T Tauri Stars (CTTSs) are young, low-mass stars which accrete material from their surrounding protoplanetary disk. To better understand accretion variability, we conducted a multi-epoch, multi-wavelength photometric monitoring campaign of four CTTSs: TW Hya, RU Lup, BP Tau, and GM Aur, in 2021 and 2022, contemporaneous with HST UV and optical spectra. We find that all four targets display significant variability in their light curves, generally on days-long timescales (but in some cases year-to-year) often due to periodicity associated with stellar rotation and to stochastic accretion variability. Their is a strong connection between mass accretion and photometric variability in all bands, but the relationship varies per target and epoch. Thus, photometry should be used with caution as a direct measure of accretion in CTTSs.