Characterizing the Ionized Gas around Massive Protostars

大质量恒星在影响银河星际介质（ISM）的能量学和化学收支方面起着主导作用。在恒星演化的早期阶段，巨大的年轻恒星物体（YSOs）通过强大的流出现象向ISM注入了大量的机械能，这是原恒星质量吸积的主要结果。反过来，这种流出活动为星团气体提供了湍流能量的主要来源。在这种情况下，在广泛的空间尺度和物理现象范围内，正确表征大规模yso与其周围包络层之间的动态相互作用是至关重要的。在这里，我建议系统地量化大质量恒星在演化的早期阶段向ISM注入的能量（即动量通量和机械光度），重点关注1000 AU量级的空间尺度。我建议通过高分辨率和高灵敏度的Jansky甚大阵列（JVLA）观测超大质量yso样本（40）的超紧凑射电连续辐射来实现这一目标。这些射电连续体观测在3个光谱波段（从6到22 GHz），角分辨率约为0.1弧秒，已经被JVLA时间分配委员会批准（约60小时），并将于2014年9月结束。

Massive stars play a dominant role in terms of their influence on the energetics and chemical budget of the Galactic Interstellar Medium (ISM). At an early stage of stellar evolution, massive young stellar objects (YSOs) inject large amounts of mechanical energy into the ISM by powerful outflow phenomena, which are a main outcome of mass accretion onto the protostar. In turn, this outflow activity provide a major source of turbulent energy for the cluster gas. In this context, it is fundamental to properly characterize the dynamical interaction between massive YSOs and their surrounding envelopes over a wide range of spatial scales and physical phenomena. Here, I propose to systematically quantify the energetics (i.e., momentum flux and mechanical luminosity) injected by massive forming stars into the ISM at their early stages of evolution, focusing on spatial scales on the order of 1000 AU. I propose to achieve this goal by means of high-resolution and high-sensitivity Jansky Very Large Array (JVLA) observations of the hyper-compact radio continuum emission of a robust sample (40) of massive YSOs. These radio continuum observations in 3 spectral bands (from 6 to 22 GHz), and with an angular resolution of about 0.1 arcsec, have already been granted by the JVLA time allocation committee (about 60 hr) and will be concluded by September 2014.