Abstract

The accretion/ejection processes in T Tauri stars are fundamental to their physical evolution, while also impacting the properties and evolution of the circumstellar material at a time when planet formation takes place. To date, the characterization of ongoing accretion processes in stellar pairs at 5-50 au scales has been challenging as high-angular resolution spectrographs are required to extract the spectral features of each component. We present the analysis of spectroscopic observations of the tight (160 mas, 25 au) T Tauri system HT Lup A/B, obtained with MUSE at the Very Large Telescope in 2021 March and July. We focus on constraining the accretion/ejection processes and variability of the secondary component HT Lup B by searching for accretion tracers by applying high-resolution spectral differential imaging techniques. We retrieve strong (signal-to-noise ratio > 5) H?, H?, and [O i]?6300 emission in both epochs. The H? and H? line fluxes showcase high variability, with variations up to 200%-300% between epochs. The fluxes are consistent with accretion rates of 3× 10?9 M ? yr?1 and 8 × 10?10 M ? yr?1 for the first and second epochs, respectively. We attribute the increased accretion activity during the first night to a “burst-like” event, followed by a relaxation period more representative of the common accretion activity of the system. The [O i]?6300 line profiles remain relatively similar between epochs and suggest ejection rates on the order of 10?9?10?10 M ? yr?1, compatible with moderate disk wind emission. Our results also indicate that the accretion processes of HT Lup B are compatible with Classical T Tauri stars, unlike previous classifications. © 2024. The Author(s). Published by the American Astronomical Society.