Protostars and Planets VI, Heidelberg, July 15-20, 2013
Disk-Disk Interactions and Orbitally-Modulated Accretion in the DQ Tau System
Bary, Jeffrey (Colgate University)
Petersen, Michael (University of Massachussetts-Amherst)
We present multi-epoch low and moderate resolution near-infrared spectra of the high eccentricity tight binary, DQ Tau. Similar to activity previously recorded in optical spectra, we see clear evidence of orbitally-modulated accretion activity phased with periastron passages in the system. However, during one of four apastron passes observed, we measure a significant enhancement in the infrared accretion indicators. The potentially anomalous accretion flare is interpreted as matter passing directly from the circumbinary disk onto one or both of the highly truncated circumstellar disks. The nature and frequency of these disk-disk interactions are important for constraining hydrodynamic models of accretion activity in such systems as well as in young planetary systems containing forming gas giants. We also explore a consistent spectral typing mismatch between atomic and molecular band absorption features. We determine that this discrepancy is consistent with the formation of the molecular features within large cool spots on the stellar surface(s) and is not due to the lower surface gravity associated with the contracting T Tauri stars. In addition to changes in continuum veiling, variations observed in the strength of the TiO bands at 0.85 and 0.88 um could be explained by spot evolution and the heating of these spots during accretion events,.
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