Herschel Observations of the T Cha Transition Disk: Constraining the Outer Disk Properties

Abstract

T Cha is a nearby (d = 100 pc) transition disk known to have an optically thin gap separating optically thick inner and outer disk components. Huelamo et al. (2011) recently reported the presence of a low-mass object candidate within the gap of the T Cha disk, giving credence to the suspected planetary origin of this gap. Here we present the Herschel photometry (70, 160, 250, 350, and 500 micron) of T Cha from the "Dust, Ice, and Gas in Time" (DIGIT) Key Program, which bridges the wavelength range between existing Spitzer and millimeter data and provide important constraints on the outer disk properties of this extraordinary system. We model the entire optical to millimeter wavelength spectral energy distribution (SED) of T Cha (19 data points between 0.36 and 3300 micron without any major gaps in wavelength coverage). T Cha shows a steep spectral slope in the far-IR, which we find clearly favors models with outer disks containing little or no dust beyond 40 AU. The full SED can be modeled equally well with either an outer disk that is very compact (only a few AU wide) or a much larger one that has a very steep surface density profile. That is, T Cha's outer disk seems to be either very small or very tenuous. Both scenarios suggest a highly unusual outer disk and have important but different implications for the nature of T Cha. Spatially resolved images are needed to distinguish between the two scenarios.

Accepted for publication in ApJ Letters

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Cited by in corpus (16)

• The Herschel DIGIT Survey of Weak-line T Tauri Stars: implications for disk evolution and dissipation
• Sculpting the disk around T Cha: an interferometric view
• New constraints on the disk characteristics and companion candidates around T Cha with VLT/SPHERE
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• Detection of the Circumstellar Disk Associated with 2MASS J0820-8003 in the eta Cha Cluster
• JWST captures a sudden stellar outburst and inner disk wall destruction
• Polycyclic aromatic hydrocarbon (PAH) abundances in the disk around T Chamaeleontis (T Cha): PAH sizes, ionization fraction, and mass during JWST observations