| Résumé | We present new BIMA observations of the massive star-forming region IRAS 23033+ 5951 in Cepheus. 3 mm continuum observations reveal that the source decomposes into at least three dusty clumps, each of which has sufficient mass to form a massive star. The most massive clump has a mass of about 225 M⊙ and appears to house the massive protostar which drives the prominent CO outflow seen in the region. Our H¹³3CN 1–0, N₂H⁺ 1–0, and H¹³CO⁺ 1–0 maps show that the three continuum sources are all embedded in an elongated structure whose long axis is perpendicular to the outflow. Both H¹³CO⁺ and H13CN peak at the geometric center of this structure, which lies between the two prominent continuum peaks. All three lines – H¹³CN, H1³CO⁺, and N₂H+–show the same velocity gradient along the long axis of their integrated intensity maps. Although the approximately 90,000 AU length of the elongated structure prohibits a disk interpretation, the fact that the dynamical and gas masses of the structure differ by only a factor of a few suggests that the structure may be partially rotationally supported. We also detect a signature of infall toward the center of the structure, seen as an asymmetrically blue HCO⁺ line where its optically thin isotope, H¹³CO⁺, is symmetric and single-peaked. |
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