A wide-angle outflow with the simultaneous presence of a high-velocity jet in the high-mass Cepheus A HW2 system
A wide-angle outflow with the simultaneous presence of a high-velocity jet in the high-mass Cepheus A HW2 system
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高质量仙王座 A HW2 系统中广角流出，同时存在高速射流
DOI：
10.1111/j.1365-2966.2010.17483.x
复制
发表时间：
2010
影响因子：
4.8
通讯作者：
P. Ho
中科院分区：
文献类型：
--
作者：
J. Torrelles;N. Patel;S. Curiel;R. Estalella;José F. Gómez;L. Rodríguez;J. Canto;G. Anglada;W. Vlemmings;G. Garay;A. Raga;P. Ho;P. Ho
我们提出了五个时代的VLBI水脉泽观测周围的大质量原恒星仙王座A HW 2与0.4 mas（0.3 Au）的分辨率。这些观测的主要目标是跟踪在早期VLBI观测中发现的显著水脉泽线性/弓形结构的演化。将我们新观测时期的数据与5年前观测到的数据进行比较，我们发现在1角秒（700 Au）的“大”尺度上，脉泽发射的主要区域仍然存在，这意味着在这段时间内，周围介质和脉泽的激发源都相对稳定。然而，在0.1弧秒（70 Au）的较小尺度上，我们看到脉泽结构的巨大变化，特别是在扩展的弓形结构R4和R5中。R4追踪了一个大小为1070 mas（50 Au）的近椭圆形斑片状环，其膨胀运动为105 mas yr −1（15 km s −1），与Gallimore及其合作者先前的结果一致。这个结构可能是由位于环中心（HW 2以南约0.18角秒）的一个尚未确认的YSO的风驱动的。另一方面，R5膨胀的气泡结构（由先前确定的位于HW 2以南0.6角秒的YSO的风驱动）目前正在星周介质中消散，并失去了以前的对称度，这表明一个非常短暂的事件。此外，我们的结果还揭示了在700 Au的尺度上，同时存在着由脉泽跟踪的相对缓慢的（10- 70 km s −1）广角外流（张开角为102 μ m），以及之前用VLA观测到的与HW 2（张开角为1018 μ m）相关的快速（1500 km s −1）高度准直的射电喷流。大质量原恒星同时存在广角外流和高度准直的喷流，这与一些低质量YSO中发现的相似。有迹象表明，来自HW 2的主风可能正在旋转。这些结果的影响，在高质量恒星的形成的研究进行了讨论。
We present five epochs of VLBI water maser observations around the massive protostar Cepheus A HW2 with 0.4 mas (0.3 au) resolution. The main goal of these observations was to follow the evolution of the remarkable water maser linear/arcuate structures found in earlier VLBI observations. Comparing the data of our new epochs of observation with those observed 5 yr before, we find that at ‘large’ scales of 1 arcsec (700 au) the main regions of maser emission persist, implying that both the surrounding medium and the exciting sources of the masers have been relatively stable during that time-span. However, at smaller scales of 0.1 arcsec (70 au) we see large changes in the maser structures, particularly in the expanding arcuate structures R4 and R5. R4 traces a nearly elliptical patchy ring of ∼70 mas size (50 au) with expanding motions of ∼5 mas yr −1 (15 km s −1 ), consistent with previous results of Gallimore and collaborators. This structure is probably driven by the wind of a still unidentified YSO located at the centre of the ring (∼0.18 arcsec south of HW2). On the other hand, the R5 expanding bubble structure (driven by the wind of a previously identified YSO located ∼0.6 arcsec south of HW2) is currently dissipating in the circumstellar medium and losing its previous degree of symmetry, indicating a very short lived event. In addition, our results reveal, at scales of ∼1 arcsec (700 au), the simultaneous presence of a relatively slow (∼10– 70 km s −1 ) wide-angle outflow (opening angle of ∼102 ◦ ), traced by the masers, and the fast (∼500 km s −1 ) highly collimated radio jet associated with HW2 (opening angle of ∼18 ◦ ), previously observed with the VLA. This simultaneous presence of a wide-angle outflow and a highly collimated jet associated with a massive protostar is similar to what is found in some low-mass YSOs. There are indications that the primary wind(s) from HW2 could be rotating. The implications of these results in the study of the formation of high-mass stars are discussed.
大质量年轻恒星W33A的星周盘、包膜和双极流出
DOI：
10.1111/j.1365-2966.2009.16077.x
发表时间：
2010
影响因子：
4.8
作者：
Davies B
通讯作者：
Davies B
DOI：
10.1088/0004-637x/693/1/406
发表时间：
2008-11
期刊：
The Astrophysical Journal
影响因子：
--
作者：
L. Moscadelli;Mark J. Reid;K. Menten;A. Brunthaler;X. Zheng;Ye Xu;Ye Xu
通讯作者：
L. Moscadelli;Mark J. Reid;K. Menten;A. Brunthaler;X. Zheng;Ye Xu;Ye Xu
揭晓 CEPHEUS A HW2 区域的主要热源
DOI：
10.1088/0004-637x/703/2/l157
发表时间：
2009
期刊：
The Astrophysical Journal
影响因子：
--
作者：
Jiménez-Serra I
通讯作者：
Jiménez-Serra I