Accretion Disks Around Young Massive Stars

《年轻大质量恒星周围的吸积盘》AST-0098524巨型恒星造就了螺旋星系的许多基本特征。它们通过其强烈的电离辐射、猛烈的外流风以及最终作为超新星爆炸而消亡，有效地决定了星际介质的性质。它们还通过触发分子尘埃和气体云核的最初坍塌来影响后续几代恒星的形成。大质量恒星形成的主要机制仍然是恒星天体物理学的突出问题之一。最有可能的是，这种机制类似于通过原恒星盘的形成和坍塌而产生低质量恒星的机制。但是，在大质量恒星的情况下，大质量原恒星的巨大辐射压力带来的恒星形成过程肯定会有重要的修改。有可能存在另一种产生大质量范围恒星的途径，但首先，努力寻找盘的特征是很重要的。通过这一奖项，PI将转向射电天文学，并利用甚大阵列(VLA)和超大型基线阵列的能力来搜索和随后研究这种类型的磁盘。VLA将被用来直接成像7毫米波长的吸积盘发出的尘埃连续辐射。VLBA将被用来以另一种方式识别吸积盘，通过1.3厘米波长的强水脉泽线，并将其用作动力学探测器。无论是否探测到吸积盘，拟议的观测都将提供对年轻大质量恒星附近物质的高角度分辨率观测。

" Accretion Disks Around Young Massive Stars"AST- 0098524Massive stars are responsible for many of the basic characteristics of spiral galaxies. They effectively dictate the properties of the interstellar medium through their strong ionizing radiation, vigorous outflowing winds and eventual demise as supernovae explosions. They also influence the formation of subsequent generations of stars by triggering the initial collapse of cloud cores of molecular dust and gas. The dominant mechanism by which high mass stars form remains one of the outstanding problems of stellar astrophysics. Most likely, the mechanism is similar to that which produces low mass stars through the formation and collapse of protostellar disks. But, in the case of massive stars, there must be important modifications to the star forming process brought on by the enormous radiation pressure from the massive protostars. The possibility exists that there is an alternative route for producing stars in the high-mass range but first it is important to look hard for the signatures of disks. Through this award the PI will turn to radio astronomy and exploit the capabilities of the Very Large Array (VLA) and the Very Large Baseline Array to search for and subsequently study disks of this type. The VLA will be used to directly image the dust continuum emission from the accretion disk at a wavelength of 7 mm. The VLBA will be used to identify accretion disks in another way, via the strong water maser line at a wavelength of 1.3 cm and to use this as a kinetic probe. Whether the accretion disks are detected or not, the proposed observations will provide high angular resolution observations of matter in the vicinity of young massive stars.