arXivDaily arXiv每日学术速递 周一至周五更新
北美退伍军人节(Veterans Day),12 日无更新
arXiv 1106.3645astro-ph.SR
收藏

X Her和TX Psc:Herschel观测到的ISM与恒星风相互作用的两个事例

X Her and TX Psc: Two cases of ISM interaction with stellar winds observed by Herschel

A. Jorissen, A. Mayer, S. Van Eck, R. Ottensamer, F. Kerschbaum, T. Ueta, P. Bergman, J. A. D. L. Blommaert, L. Decin, M. A. T. Groenewegen, J. Hron, W. Nowotny… 展开作者

A. Jorissen, A. Mayer, S. Van Eck, R. Ottensamer, F. Kerschbaum, T. Ueta, P. Bergman, J. A. D. L. Blommaert, L. Decin, M. A. T. Groenewegen, J. Hron, W. Nowotny, H. Olofsson, Th. Posch, L. O. Sjouwerman, B. Vandenbussche, C. Waelkens

摘要:

作为大型MESS(演化恒星质量损失)保证时间密钥计划的一部分,用赫歇尔卫星上的PACS仪器在70和160微米处对渐近巨星分支(AGB)恒星X Her和TX Psc进行了成像。这些图像揭示了一个轴对称的扩展结构,其轴沿着恒星的空间运动定向。这种扩展的结构很可能是由AGB星喷出的风与周围的星际介质(ISM)相互作用形成的。正如数值模拟所预测的那样,风-ISM界面的详细结构取决于恒星+风和ISM之间的相对速度,这对这两颗恒星来说很大(X Her和TX Psc分别为108和55 km/s)。在这两种情况下,上游都有一个致密的团块,其起源还没有完全阐明,但这可能是风-ISM激波中某些不稳定性的标志。X Her和TX Psc的解卷积图像揭示了沿着最外层细丝的几个离散结构,这可能是开尔文-亥姆霍兹涡旋。最后,TX Psc被一个几乎是圆形的环所包围(终端冲击的签名?)与外部结构更好的纤维形成对比。类似的内部环形结构似乎也存在于X Her中,尽管不太清楚。

英文摘要:

The asymptotic giant branch (AGB) stars X Her and TX Psc have been imaged at 70 and 160 microns with the PACS instrument onboard the Herschel satellite, as part of the large MESS (Mass loss of Evolved StarS) Guaranteed Time Key Program. The images reveal an axisymmetric extended structure with its axis oriented along the space motion of the stars. This extended structure is very likely to be shaped by the interaction of the wind ejected by the AGB star with the surrounding interstellar medium (ISM). As predicted by numerical simulations, the detailed structure of the wind-ISM interface depends upon the relative velocity between star+wind and the ISM, which is large for these two stars (108 and 55 km/s for X Her and TX Psc, respectively). In both cases, there is a compact blob upstream whose origin is not fully elucidated, but that could be the signature of some instability in the wind-ISM shock. Deconvolved images of X Her and TX Psc reveal several discrete structures along the outermost filaments, which could be Kelvin-Helmholtz vortices. Finally, TX Psc is surrounded by an almost circular ring (the signature of the termination shock?) that contrasts with the outer, more structured filaments. A similar inner circular structure seems to be present in X Her as well, albeit less clearly.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑