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arXiv 1401.6986astro-ph.GA
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CALYPSO IRAM-PdBI调查的第一批结果。I. NGC1333-IRAS2A内膜的运动

First results from the CALYPSO IRAM-PdBI survey. I. Kinematics of the inner envelope of NGC1333-IRAS2A

S. Maret, A. Belloche, A. J. Maury, F. Gueth, Ph. André, S. Cabrit, C. Codella, S. Bontemps

备注：
Accepted for publication in A&A letters
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摘要：

在几百天文单位的尺度上，0级原恒星的结构和运动学知之甚少。最近的观测显示，在L1527-IRS和VLA 1623 A中存在直径为150-180 AU的开普勒盘，但不清楚这种盘是否在0类原恒星中常见。在这里，我们提出了在NGC 1333-IRAS 2A的两个甲醇线的高角分辨率观测。我们认为，这些线探测的内部信封，我们用它们来研究该地区的运动学。我们的观察表明，存在一个边缘的速度梯度垂直于流出的方向。然而，沿梯度方向的位置速度图似乎与开普勒圆盘不一致。相反，我们认为，发射起源于下降，也许缓慢旋转的信封，围绕中央原恒星的0.1-0.2 M $_\odot$。如果存在盘，它比L1527-IRS的盘小，可能表明NGC 1333-IRAS 2A更年轻。

英文摘要：

The structure and kinematics of Class 0 protostars on scales of a few hundred AU is poorly known. Recent observations have revealed the presence of Keplerian disks with a diameter of 150-180 AU in L1527-IRS and VLA1623A, but it is not clear if such disks are common in Class 0 protostars. Here we present high-angular-resolution observations of two methanol lines in NGC1333-IRAS2A. We argue that these lines probe the inner envelope, and we use them to study the kinematics of this region. Our observations suggest the presence of a marginal velocity gradient normal to the direction of the outflow. However, the position velocity diagrams along the gradient direction appear inconsistent with a Keplerian disk. Instead, we suggest that the emission originates from the infalling and perhaps slowly rotating envelope, around a central protostar of 0.1-0.2 M$_\odot$. If a disk is present, it is smaller than the disk of L1527-IRS, perhaps suggesting that NGC1333-IRAS2A is younger.

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