ALMA Monitoring of Millimeter Line Variation in IRC +10216. I. Overview of Millimeter Variability
ALMA Monitoring of Millimeter Line Variation in IRC +10216. I. Overview of Millimeter Variability
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DOI：
10.3847/1538-4357/ab3d37
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发表时间：
2019-04
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通讯作者：
J. He;T. Kami'nski;R. Mennickent;V. Shenavrin;D. Mardones;Wei Wang;B. Tang;M. Schmidt;R. Szc
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作者：
J. He;T. Kami'nski;R. Mennickent;V. Shenavrin;D. Mardones;Wei Wang;B. Tang;M. Schmidt;R. Szc
毫米线的时间变化是演化恒星研究的一个新方向。它有可能从时间维度探索动力风发射过程。我们在这里报告的第一个阿塔卡马大型毫米阵列（阿尔马）的结果，涵盖817天的持续监测的1.1毫米线的原型碳星星IRC +10216。监测工作是用7米的小型阵列进行的，用克里米亚的1.25米望远镜进行红外线监测。在250和270 GHz之间的累积光谱的高灵敏度，覆盖了总共10.7.2 GHz，使我们能够检测到约148个已知的跃迁的20个分子，连同更多的同位素，和81个未识别的线。所有检测到的线特征的变异性的概述是在频谱图。虽然发现少数谱线在时间上很可能是稳定的，但大多数其他谱线要么在相位上大致变化，要么与近红外光成正比。阿尔马数据中有几条线的变化与现有的单碟监测结果一致，而其他几条则不一致，这需要在拱星包层中找到一种未知的机制来解释。
Temporal variation of millimeter lines is a new direction of research for evolved stars. It has the potential to probe the dynamical wind-launching processes from a time dimension. We report here the first Atacama Large Millimeter Array (ALMA) results that cover 817 days of ongoing monitoring of 1.1 mm lines in the archetypal carbon star IRC +10216. The monitoring is done with the compact 7 m array and in infrared with a 1.25 m telescope in Crimea. High sensitivity of the cumulative spectra covering a total of ∼7.2 GHz between 250 and 270 GHz has allowed us to detect about 148 known transitions of 20 molecules, together with more of their isotopologues, and 81 unidentified lines. An overview of the variabilities of all detected line features is presented in spectral plots. Although a handful of lines are found to be very possibly stable in time, most other lines are varying either roughly in phase or in anticorrelation with the near-infrared light. Several lines have their variations in the ALMA data coincident with existing single-dish monitoring results, while several others do not, which requires a yet-unknown mechanism in the circumstellar envelope to explain.