论文标题

来自金牛座的深层嵌入物体的低速双极流出,Atacama紧凑型阵列

A low-velocity bipolar outflow from a deeply embedded object in Taurus revealed by the Atacama Compact Array

论文作者

Fujishiro, Kakeru, Tokuda, Kazuki, Tachihara, Kengo, Takashima, Tatsuyuki, Fukui, Yasuo, Zahorecz, Sarolta, Saigo, Kazuya, Matsumoto, Tomoaki, Tomida, Kengo, Machida, Masahiro N., Inutsuka, Shu-ichiro, André, Philippe, Kawamura, Akiko, Onishi, Toshikazu

论文摘要

第一个静水压核是在恒星形成过程中形成的第一个准静态物体,它仍然是Prestellar和Protostellar阶段之间的观察性缺失联系,这主要是由于其寿命短。尽管我们尚未建立一种明确的方法来识别这一稀有物体,但最近的理论研究预测,第一核具有毫米连续体的发射和低速流出,并具有较宽的开放角度。对附近星形成区域的大量$“ $ starless $” $核心的大量连续/流出调查可作为探路者。我们在金牛座观察了32个Prestellar核心,平均密度为$ \ gtrsim $ 10 $^5 $ cm $^{ - 3} $在1.3毫米连续体和分子线中使用Atacama大毫米/亚毫米级/亚毫米级$ - $ - $ -ATACAMA COMPACTACTACTACTACTACTACTARAY ARRAY ARRAY ARRAY ARRAY(ALMA $ - $ ACA)站立模式。在目标中,MC35毫米集中在金牛座的最密集$“ $ starless $” $内核之一中,在$^{12} $ CO(2-1)线上蓝色/红移翅膀,表明有深入嵌入的对象驱动分子流出。观察到的速度和可能的流出裂片的尺寸为2-4 km s $^{ - 1} $,$ \ sim $ 2 $ \ times $ 10 $^3 $ au,并且计算的动态时间为$ \ sim $ 10 $^3 $^3 $ yr。除此之外,核心是我们样本中最强的N $ _2 $ d $^{+} $(3-2)发射器之一。迄今为止,所有观察到的签名与关于第一个静水压核的任何理论预测均未冲突,因此MC35-mm是金牛座分子云中唯一的第一核候选者。

The first hydrostatic core, the first quasi-hydrostatic object formed during the star formation process, is still the observational missing link between the prestellar and protostellar phases, mainly due to its short lifetime. Although we have not established a clear method to identify this rare object, recent theoretical studies predict that the first core has millimeter continuum emission and low-velocity outflow with a wide opening angle. An extensive continuum/outflow survey toward a large number of $"$starless$"$ cores in nearby star-forming regions works as a pathfinder. We observed 32 prestellar cores in Taurus with an average density of $\gtrsim$10$^5$ cm$^{-3}$ in 1.3 mm continuum and molecular lines using the Atacama Large Millimeter/submillimeter Array$-$Atacama Compact Array (ALMA$-$ACA) stand-alone mode. Among the targets, MC35-mm centered at one of the densest $"$starless$"$ cores in Taurus has blueshifted/redshifted wings in the $^{12}$CO (2-1) line, indicating that there is deeply embedded object driving molecular outflow. The observed velocities and sizes of the possible outflow lobes are 2-4 km s$^{-1}$, and $\sim$2 $\times$10$^3$ au, respectively, and the dynamical time is calculated to be $\sim$10$^3$ yr. In addition to this, the core is one of the strongest N$_2$D$^{+}$ (3-2) emitters in our sample. All of the observed signatures do not conflict with any of the theoretical predictions about the first hydrostatic core so far, and thus MC35-mm is unique as the only first-core candidate in the Taurus molecular cloud.

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