ALMA sub-mm maser and dust distribution of VY Canis Majoris
ALMA sub-mm maser and dust distribution of VY Canis Majoris
复制标题
VY Canis Majoris 的 ALMA 亚毫米脉泽和尘埃分布
DOI：
10.1051/0004-6361/201425024
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发表时间：
2014
影响因子：
6.5
通讯作者：
A. Zijlstra
中科院分区：
文献类型：
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作者：
A. M. Richards;C. Impellizzeri;Elizabeth Humphreys;C. Vlahakis;W. Vlemmings;A. Baudry;E. Beck;L. Decin;S. Etoka;M. Gray;G. M. Harper;Todd R. Hunter;P. Kervella;P. Kervella;P. Kervella;F. Kerschbaum;I. McDonald;G. Melnick;Sebastien Muller;D. Neufeld;E. O’Gorman;S. Parfenov;Alison B. Peck;H. Shinnaga;A. M. Sobolev;L. Testi;L. Uscanga;A. Wootten;J. Yates;A. Zijlstra
目标。凉爽、进化的恒星有丰富而丰富的风。到目前为止，观测结果还没有完全限制这些风的形成和加速的模型。我们需要更好地理解动力学，从脉动的恒星表面到大约10个恒星半径，在这个范围内，尘埃上的辐射压力是完全有效的。一些红色超巨星周围的不对称星云暗示了附加力的作用。方法：研究方法。我们检索了ALMA科学验证数据，提供了来自VY CMA的亚毫米线和连续发射的图像。这使我们能够以毫角秒的精度定位水脉泽，并分辨尘埃连续体。结果。658、321和325 GHz脉泽位于不规则的厚壳中，距离膨胀中心越来越远。这是第一次被确认为恒星位置，与最明亮的连续发射的NW方向的紧凑峰相吻合。脉泽壳相互重叠，但在高达10Au的尺度上相互避开。它们的分布与激励模型大体一致，但条件和运动学由于风的碰撞、聚集和不对称而变得复杂。
Aims. Cool, evolved stars have copious, enriched winds. Observations have so far not fully constrained models for the shaping and acceleration of these winds. We need to understand the dynamics better, from the pulsating stellar surface to similar to 10 stellar radii, where radiation pressure on dust is fully effective. Asymmetric nebulae around some red supergiants imply the action of additional forces. Methods. We retrieved ALMA Science Verification data providing images of sub-mm line and continuum emission from VY CMa. This enables us to locate water masers with milli-arcsec accuracy and to resolve the dusty continuum. Results. The 658, 321, and 325 GHz masers lie in irregular, thick shells at increasing distances from the centre of expansion. For the first time this is confirmed as the stellar position, coinciding with a compact peak offset to the NW of the brightest continuum emission. The maser shells overlap but avoid each other on scales of up to 10 au. Their distribution is broadly consistent with excitation models but the conditions and kinematics are complicated by wind collisions, clumping, and asymmetries.