DETECTION OF A 45 AU RADIUS SOURCE AROUND L1551-IRS5 - A POSSIBLE ACCRETION DISK

We have made interferometric and single-dish observations of the continuum emission from L1551-IRS 5 at wavelengths from 1.0 mm to 6.2 cm. These observations show that, at millimeter wavelengths, there are two distinct components to the source, an envelope with a radius ∼ 2000 AU, and a compact core with a radius ≤64 AU. In both components, the continuum radiation is due predominantly to thermal dust emission. The compact core has a large optical depth, indicating a high column density ( ∼ 1000 g cm-2). By modeling the temperature in the region of the compact core, we show that its size must lie in the range 45 ± 20 AU. The compact core is most plausibly identified with an accretion, or preplanetary, disk around the star, although the present observations do not have sufficient angular resolution to rule out other structures.