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Classical T Tauri stars (cTTs) accrete from their circumstellar disk. Thematerial falls onto the stellar surface, producing an accretion shock, whichgenerates veiling in a star's spectra. In addition, the shock causes alocalized accretion spot at the level of the chromosphere. Our goal is toinvestigate the accretion, particularly the mass accretion rates (Macc), forthe cTTs DK Tau, over two periods of 17 and 29 days, using two differentprocedures for comparison purposes. The first method relies on the derivationof the accretion luminosity via accretion-powered emission lines. The secondcompares the variability of the optical veiling with accretion shock models todetermine mass accretion rates. We used observations taken in 2010 and 2012with the ESPaDOnS spectropolarimeter at the CFHT. We find peak values of theveiling (at 550 nm) ranging from 0.2 to 1.3, with a steeper trend across thewavelength range for higher peak values. When using the accretion-poweredemission lines, we find mass accretion rate values ranging fromlog(Macc[Msol/yr]) = -8.20 to log(Macc[Msol/yr]) = -7.40. This agrees with thevalues found in the literature, as well as the values calculated using theaccretion shock models and the veiling. In addition, we identify a power-lawcorrelation between the values of the accretion luminosity and the opticalveiling. For the 2010 observations, using the values of the filling factors(which represent the area of the star covered by an accretion spot) derivedfrom the shock models, we infer that the accretion spot was located between +45degrees and +75 degrees in latitude. We show that both methods of determiningthe mass accretion rate yield similar results. We also present a helpful meansof confirming the accretion luminosity values by measuring the veiling at asingle wavelength in the optical.

Correlation between the optical veiling and accretion properties: A case study of the classical T Tauri star DK Tau