A search for evidence of cold dust around naked T Tauri stars

We present results of millimeter/submillimeter photometry of 16 naked T Tauri stars (NTTS), 11 of which lie in the nearby Taurus-Auriga star-forming region. Our objective was to search for evidence of cold circumstellar dust, which could exist around these objects in the form of remnant disks if NTTS evolved from classical T Tauri stars. The only star detected at the primary observing wavelength of 1100 μm was V836 Tau, which was also detected at 800 μm with an upper limit obtained at 450 μm. Its spectral energy distribution longward of 10 μm is consistent with that expected for a flat, axisymmetric, moderately active disk of mass ∼0.04script M sign_⊙, assuming a dust opacity law N_ν =0.1(ν/10¹² Hz)^1.0 cm² g^-1. Upper limits on the disk masses of undetected stars in Taurus-Auriga are typically 0.02script M sign_⊙ (3σ), for an assumed temperature ≥6 K at the outer disk radius. We argue that the high levels of magnetic activity found in NTTS may produce detectable gyrosynchrotron emission at millimeter wavelengths, and recommend future high-sensitivity searches for the short-term flux variability characteristic of such emission.