Characterizing the Ionized Gas around Massive Protostars

大质量恒星在影响银河系星际介质（ISM）的能量和化学收支方面起着主导作用。在恒星演化的早期阶段，大质量年轻恒星（YSO）注入大量的机械能到ISM强大的外流现象，这是一个主要的结果，质量吸积到原恒星。反过来，这种外流活动为团簇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中正确描述大质量YSO及其周围包层之间的动力学相互作用至关重要。在这里，我建议系统地量化能量学（即，动量通量和机械光度）注入到ISM在其演化的早期阶段的大质量形成的恒星，集中在1000 Au数量级的空间尺度。我建议通过高分辨率和高灵敏度的Jansky甚大阵列（JVLA）观测一个强大的样本（40）的大规模YSO的超紧凑无线电连续辐射来实现这一目标。这些射电连续谱观测在3个谱带（从6到22 GHz），角分辨率约为0.1角秒，已经得到JVLA时间分配委员会的批准（约60小时），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.