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-mu-m was V836 Tau, which was also detected at 800-mu-m with an upper limit obtained at 450-mu-m. Its spectral energy distribution longward of 10-mu-m is consistent with that expected for a flat, axisymmetric, moderately active disk of mass approximately 0.04M., assuming a dust opacity law kappa-nu = 0.1(nu/10(12) Hz)1.0 cm2 g-1. Upper limits on the disk masses of undetected stars in Taurus-Auriga are typically 0.02M. (3-sigma), for an assumed temperature greater-than-or-equal-to 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.