IDENTIFICATION OF A COLLAPSING PROTOSTAR

The globular molecular cloud B335 contains a single, deeply embedded, far-infrared source. Our recent observations of H2CO and CS lines towa rd this source provide direct kinematic evidence for collapse. Both th e intensity and detailed shape of the line profiles match those expect ed from inside-out collapse inside a radius of 0.036 pc. The collapse began about 1.5 x 10(5) years ago, similar to the onset of the outflow . The mass accretion rate is about 10 times the outflow rate, and abou t 0.4 M. should have now accumulated in the star and disk. Because B33 5 rotates only very slowly, any disk would still be very small (about 3 AU). The accretion luminosity should be adequate to power the observ ed luminosity. Consequently, we believe that B335 is indeed a collapsi ng protostar.