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We report the detection of an anomalous accretion flare in the tighteccentric pre-main-sequence binary system DQ Tau. In a multi-epoch surveyconsisting of randomly acquired low to moderate resolution near-infraredspectra obtained over a period of almost ten years, we detect a significant andsimultaneous brightening of four standard accretion indicators (CaII infraredtriplet, the Paschen and Brackett series HI lines, and HeI 1.083 um), onback-to-back nights (phase = 0.372, 0.433) with the flare increasing instrength as the system approached apastron (phase = 0.5). The mass accretionrate measured for the anomalous flare is nearly an order of magnitude strongerthan the average quiescent rate. While previous observations established thatfrequent, periodic accretion flares phased with periastron passages occur inthis system, these data provide evidence that orbitally-modulated accretionflares occur near apastron, when the stars make their closest approach to thecircumbinary disk. The timing of the flare suggests that this outburst is dueto interactions of the stellar cores (or the highly truncated circumstellardisks) with material in non-axisymmetric structures located at the inner edgeof the circumbinary disk. We also explore the optical/infrared spectral typemismatch previously observed for T Tauri stars and successfully model the shapeof the spectra from 0.8 to 1.0 um and the strengths of the TiO and FeH bands asmanifestations of large cool spots on the surfaces of the stellar companions inDQ Tau. These findings illustrate that a complete model of near-infraredspectra of many T Tauri stars must include parameters for spot filling factorsand temperatures.

Anomalous Accretion Activity and the Spotted Nature of the DQ Tau Binary System