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RW Aur A is a CTTS that has suddenly undergone three major dimming eventssince 2010. We aim to understand the dimming properties, examine accretionvariability, and derive the physical properties of the inner disc traced by theCO ro-vibrational emission at NIR wavelengths (2.3 mic).  We compared two epochs of X-Shooter observations, during and after thedimming. We modelled the rarely detected CO bandhead emission in both epochs toexamine whether the inner disc properties had changed. The SED was used toderive the extinction properties of the dimmed spectrum and compare theinfrared excess between the two epochs. Lines tracing accretion were used toderive the mass accretion rate in both states. The CO originates from a regionwith physical properties of T=3000 K, N$_{CO}$=1x10$^{21}$ cm$^{-2}$ andvsini=113 km/s. The extinction properties of the dimming layer were derivedwith the effective optical depth ranging from teff 2.5-1.5 from the UV to theNIR. The inferred mass accretion rate Macc is $1.5x 10^{-8}$ Msun/yr and $\sim2x 10^{-8}$ Msun/yr after and during the dimming respectively. By fitting theSED, additional emission is observed in the IR during the dimming event fromdust grains with temperatures of 500-700K. The physical conditions traced bythe CO are similar for both epochs, indicating that the inner gaseous discproperties do not change during the dimming events. The extinction curve isflatter than that of the ISM, and large grains of a few hundred microns arethus required. When we correct for the observed extinction, Macc is constant inthe two epochs, suggesting that the accretion is stable and therefore does notcause the dimming. The additional hot emission in the NIR is located at about0.5 au from the star. The dimming events could be due to a dust-laden wind, asevere puffing-up of the inner rim, or a perturbation caused by the recentstar-disc encounter.

Exploring the dimming event of RW Aur A through multi-epoch VLT/X-Shooter spectroscopy