The Inner Disk and Accretion Flow of the Close Binary DQ Tau

Abstract

We present multi-epoch optical and near-infrared (NIR) photometry and spectroscopy of the spectroscopic binary T Tauri star DQ Tau. The photometric monitoring, obtained using SMARTS ANDICAM, recovers the previously-seen correlation between optical flux and the 15.8-day binary orbital period, with blue flux peaks occurring close to most observed periastron passages. For the first time, we find an even more consistent correlation between orbital period and NIR brightness and color. The onset of pulse events in the NIR on average precedes those in the optical by a few days, with the rise usually starting near apastron orbital phase. We further obtained five epochs of spectroscopy using IRTF SpeX, with a wavelength range of 0.8 to 5 microns, and derived spectra of the infrared excess emission. The shape and strength of the excess varies with time, with cooler and weaker characteristic dust emission (T ~ 1100-1300 K) over most of the binary orbit, and stronger/warmer dust emission (T ~ 1600 K, indicative of dust sublimation) just before periastron passage. We suggest our results are broadly consistent with predictions of simulations of disk structure and accretion flows around close binaries, with the varying dust emission possibly tracing the evolution of accretion streams falling inwards through a circumbinary disk cavity and feeding the accretion pulses traced by the optical photometry and NIR emission lines. However, our results also show more complicated behavior that is not fully explained by this simple picture, and will require further observations and modeling to fully interpret.

accepted to ApJ

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• A Low-Mass Pre-Main-Sequence Eclipsing Binary in Lower Centaurus Crux Discovered with TESS
• Double-peaked OI profile: a likely signature of the gaseous ring around KH 15D
• Time-resolved protoplanetary disk physics in DQ Tau with JWST
• The Young Binary DQ Tau Produces Another X-ray Flare Near Periastron
• Accretion process, magnetic fields, and apsidal motion in the pre-main sequence binary DQ Tau
• Characterising the orbit and circumstellar environment of the high-mass binary MWC 166 A
• The influence of tight binaries on proto-planetary disk masses
• Accretion Kinematics in the T Tauri Binary TWA 3A: Evidence for Preferential Accretion onto the TWA 3A Primary