We present the high-resolution (2"-4") images of the molecular envelopes surrounding the evolved stars, V Hya, VY CMa, and π1 Gru observed with the Submillimeter Array. The CO J=2-1 and 3-2 images of the carbon star V Hya show that the circumstellar structure of this star consists of three kinematic components; there is a flattened disk-like envelope that is expanding with a velocity of ~16 km s-1, the second component is the medium-velocity wind having a deprojected velocity of 40-120 km s-l moving along the disk plane, and the third one is the bipolar molecular jet having an extreme velocity of 70-185 km s-l. The axis of this high velocity jet is perpendicular to the plane of the disk-like envelope. We found that the circumstellar structure of the S-star π1 Gru traced by the CO J =2-1 resembles that of V Hya quite closely; the star is surrounded by the expanding disk-like envelope and is driving the medium-velocity wind along the disk plane. We also obtained the excellent images of VY CMa with the CO and 13CO J=2-1 and SO 65-54 lines. The maps of three molecular lines show that the envelope has a significant velocity gradient in the east-west direction, suggesting that the envelope surrounding VY CMa is also flattened and expanding along its radial direction. The high-resolution images obtained with the SMA show that some AGB stars are associated with the asymmetric mass loss including the equatorial wind and bipolar jet.

• NAOMI HIRANO(Academia Sinica, Institute of Astronomy and Astrophysics)
• PO-JIAN CHIU(Academia Sinica, Institute of Astronomy and Astrophysics)
• SEBASTIEN MULLER(Academia Sinica, Institute of Astronomy and Astrophysics)
• DINH-V TRUNG(Academia Sinica, Institute of Astronomy and Astrophysics)