Another deep dimming of the classical T Tauri star RW Aur A

Abstract

Context. RW Aur A is a classical T Tauri star (CTTS) with an unusually rich emission line spectrum. In 2014 the star faded by ~ 3 magnitudes in the V band and went into a long-lasting minimum. In 2010 the star suffered from a similar fading, although less deep. These events in RW Aur A are very unusual among the CTTS, and have been attributed to occultations by passing dust clouds. Aims. We want to find out if any spectral changes took place after the last fading of RW Aur A with the intention to gather more information on the occulting body and the cause of the phenomenon. Methods. We collected spectra of the two components of RW Aur. Photometry was made before and during the minimum. Results. The overall spectral signatures reflecting emission from accretion flows from disk to star did not change after the fading. However, blue-shifted absorption components related to the stellar wind had increased in strength in certain resonance lines, and the profiles and strengths, but not fluxes, of forbidden lines had become drastically different. Conclusions. The extinction through the obscuring cloud is grey indicating the presence of large dust grains. At the same time, there are no traces of related absorbing gas. The cloud occults the star and the interior part of the stellar wind, but not the wind/jet further out. The dimming in 2014 was not accompanied by changes in the accretion flows at the stellar surface. There is evidence that the structure and velocity pattern of the stellar wind did change significantly. The dimmings could be related to passing condensations in a tidally disrupted disk, as proposed earlier, but we also speculate that large dust grains have been stirred up from the inclined disk into the line-of-sight through the interaction with an enhanced wind.

arXiv comment5 pages, 5 figures, Accepted for publication in A&A

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• The disappearing act: A dusty wind eclipsing RW Aur
• Star-disk interactions in multi-band photometric monitoring of the classical T Tauri star GI Tau
• Recurring Occultations of RW Aurigae by Coagulated Dust in the Tidally Disrupted Circumstellar Disk
• Exploring the dimming event of RW Aur A through multi-epoch VLT/X-Shooter spectroscopy
• The Mysterious Dimmings of the T Tauri Star V1334 Tau
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• The nature of the 2014-2015 dim state of RW Aur revealed by X-ray, optical, and NIR observations
• Stable and Unstable Regimes of Mass Accretion onto RW Aur A
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• Time-Variable Jet Ejections from RW Aur A, RY Tau and DG Tau
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• DM Ori: A Young Star Occulted by a Disturbance in its Protoplanetary Disk
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• RW Aur A : SpeX Spectral Evidence for Differentiated Planetesimal Formation, Migration and Destruction in an 3 Myr Old Excited CTTS System
• MINDS. Young binary systems with JWST/MIRI: Variable water-rich primaries and extended emission
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