论文标题

研究化学丰富区域内巨大的年轻恒星物体的进攻射流

Studying a precessing jet of a massive young stellar object within a chemically rich region

论文作者

Paron, S., Mast, D., Fariña, C., Areal, M. B., Ortega, M. E., Martinez, N. C., Peña, M. Celis

论文摘要

除了对大规模的年轻恒星物体和流出的大规模调查和目录外,还需要对特定来源进行专门研究,其中对高角度观察(主要是近IR和MM)进行了深入分析,以阐明与大型恒星形成相关的过程。银河源G079.1272+02.2782(g79)(约1.4 kpc)是进行此类研究的理想来源。使用双子座北部的NIFS进行了近红外积分光谱观测。光谱和角度的分辨率使我们能够对源及其南部喷气机进行详细的研究,从而解决了尺寸为200至300 au的结构。作为补充,分析了从JCMT和IRAM 300M望远镜数据库中检索的毫米数据,以更大的空间尺度研究分子气体。对向南延伸的射流的分析显示,在2.2 um连续体处的软木螺旋类似结构,强烈表明该喷射是进攻性的。喷射速度以30-43 km/s的速度估计,它沿着视线降临。我们建议进动可能是由可能二进制系统产生的重力潮汐效应产生的,并且我们估计的喷气进液周期约为10^3年,表明慢速射流与观察到的螺旋特征一致。对沿喷气机的H2线的分析使我们能够详细研究该喷气机产生的弓震。我们发现,这种弓震确实是由C型冲击产生的,并且观察到我们沿着视线的倾斜角度来到我们身边。通过在较大的空间尺度上分析分子流出的分析证实了这一点。对毫米波长的几种分子物种的简要分析表明,在分子块的外层中形成了复杂的化学反应,其中MYSO G79嵌入了其中。

In addition to the large surveys and catalogs of massive young stellar objects and outflows, dedicated studies of particular sources, in which high-angular observations (mainly at near-IR and mm) are analyzed in depth, are needed to shed light on the processes involved in the formation of massive stars. The galactic source G079.1272+02.2782 (G79), a MYSO at about 1.4 kpc, is an ideal source to carry out this kind of studies. Near-IR integral field spectroscopic observations were carried out using NIFS at Gemini-North. The spectral and angular resolutions, allow us to perform a detailed study of the source and its southern jet, resolving structures with sizes between 200 and 300 au. As a complement, millimeter data retrieved from the JCMT and the IRAM 30m telescope databases were analyzed to study the molecular gas at a larger spatial scale. The analysis of a jet extending southwards shows cork-screw like structures at 2.2 um continuum, strongly suggesting that the jet is precessing. The jet velocity is estimated in 30-43 km/s and it is coming to us along the line of sight. We suggest that the precession may be produced by the gravitational tidal effects generated in a probable binary system, and we estimate a jet precession period of about 10^3 yr, indicating a slow-precessing jet, which is in agreement with the observed helical features. An analysis of H2 lines along the jet allows us to investigate in detail a bow-shock produced by this jet. We find that this bow-shock is indeed generated by a C-type shock and it is observed coming to us, with some inclination angle, along the line of sight. This is confirmed by the analysis of molecular outflows at a larger spatial scale. A brief analysis of several molecular species at millimeter wavelengths indicates a complex chemistry developing at the external layers of the molecular clump in which MYSO G79 is embedded.

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