2001ApJ...552L..59Y

Aperture synthesis observations of dust continuum emission at 2 mm from the class I object Haro 6-5B, made with the Nobeyama Millimeter Array, are presented. A disklike structure that coincides with the dark lane in the visible and near-infrared images is clearly resolved with a small synthesized beam of 1".33x1".21 with its position angle (P.A.) of 134°. The beam-deconvolved size of the disk is 2".33x0".97 at P.A.=138°, and the total flux density is 36.7±2.6 mJy. The radius and inclination angle of the disk derived from the image are 309±18 AU and 67°±5°, respectively. By model fitting of the spectral energy distribution of Haro 6-5B with these values, the power-law index of the dust opacity, β, is derived to be 1.05±0.04 and the disk mass is calculated to be 0.021±0.002 M_☉. No extended emission with 1000 AU scale is detected, suggesting that the envelope around Haro 6-5B has been almost dissipated and that the object is a transient source from the protostar stage to the T Tauri stage.