Violent environment of the inner disk of RW Aur A probed by the 2010 and 2015 dimming events

Abstract

RW Aur is a young binary system showing strong signatures of a recent tidal encounter between the circumprimary disk and the secondary star. The primary star has recently undergone two major dimming events ($\Delta$mag $\approx$ 2 in V-band), whose origin is still under debate. To shed light on the mechanism leading to the dimming events, we study the extinction properties, accretion variability, and gas kinematics using absorption lines from the material obscuring star RW Aur A. We compare our moderate resolution X-Shooter spectra of the dim state of RW Aur A with other spectral observations. In particular, we analyse archival high resolution UVES spectra obtained during the bright state of the system, in order to track the evolution of the spectral properties across the second dimming event. The spectrum obtained during the dim state shows narrow absorption lines in the Na and K optical doublets, where the former is saturated. With a velocity of -60 km/s these lines indicate that during the dim state the disk wind is either enhanced, or significantly displaced into the line of sight. The photometric evolution across the dimming event shows a gray extinction, and is correlated with a significant reduction of the EW of all photospheric lines. Emission lines tracing accretion do not vary significantly across the dimming. We conclude that the dimming event is related to a major perturbation on the inner disk. We suggest that the inner disk is occulting (most of) the star, and thus its photosphere, but is not occulting the accretion regions within a few stellar radii. Since observations of the outer disk indicate that the disk is modestly inclined (45 - 60 deg), we propose that the inner disk might be warped by a yet unseen (sub-)stellar companion, which may also explain the 2.77 day periodic variability of the spectral lines.

10 pages, 8 figures, accepted for publication in A&A

References in corpus (12)

• Magnetospheric accretion-ejection processes in the classical T Tauri star AA
• Shadows cast by a warp in the HD 142527 protoplanetary disk
• Results of the ROTOR-program. I. The long-term photometric variability of classical T Tauri stars
• A tidal encounter caught in the act: modelling a star-disc fly-by in the young RW Aurigae system
• Near-Infrared Interferometric, Spectroscopic, and Photometric Monitoring of T Tauri Inner Disks
• CO/H2 Abundance Ratio ~ 10^{-4} in a Protoplanetary Disk
• Modelling MHD accretion-ejection - episodic ejections of jets triggered by a mean-field disk dynamo
• Another deep dimming of the classical T Tauri star RW Aur A
• The disappearing act: A dusty wind eclipsing RW Aur
• V409 Tau As Another AA Tau: Photometric Observations of Stellar Occultations by the Circumstellar Disk
• The peculiar dipping events in the disk-bearing young-stellar object EPIC 204278916
• Probing the presence of planets in transition discs' cavities via warps: the case of TW Hya

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