The inner structure of the TW Hya Disk as revealed in scattered light

Abstract

We observe a significant change in the TW Hya disk interior to 40~AU via archival unpolarized multi-wavelength Hubble Space Telescope/STIS and NICMOS images with an inner working angle (IWA) of 0\farcs4 (22~AU). Our images show the outer edge of a clearing at every wavelength with similar behavior, demonstrating that the feature is structural, rather than due to some property of polarized light in the disk. We compare our observations to those taken by Akiyama et al. (2015) and Rapson et al. (2015), and discuss the spectral evolution of the disk interior to 80~AU. We construct a model with two gaps: one at 30~AU and one at 80~AU that fit the observed surface brightness profile but overpredicts the absolute brightness of the disk. Our models require an additional dimming to be consistent with observations, which we tentatively ascribe to shadowing. The gap structures seen in scattered light are spatially coincident with sub-mm detections of CO and N${}_2$H${}^{+}$, and are near expected condensation fronts of these molecular species, providing tentative evidence that the structures seen in scattered light may be correlated with chemical changes in the disk.

13 pages, 3 figures, accepted to ApJ Letters

References in corpus (6)

• An Optical Spectroscopic Study of T Tauri Stars. I. Photospheric Properties
• Evidence of fast pebble growth near condensation fronts in the HL Tau protoplanetary disk
• An Inner Hole in the Disk around TW Hydrae Resolved in 7 Millimeter Dust Emission
• Discovery of a Disk Gap Candidate at 20 AU in TW Hydrae
• The HD 163296 Circumstellar Disk in Scattered Light: Evidence of Time-Variable Self-Shadowing
• Steepening of the 820 micron continuum surface-brightness profile signals dust evolution in TW Hya's disk

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• Gas and Dust Shadows in the TW Hydrae Disk