A SEARCH FOR VERY LOW-LUMINOSITY OBJECTS IN GOULD BELT CLOUDS
A SEARCH FOR VERY LOW-LUMINOSITY OBJECTS IN GOULD BELT CLOUDS
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DOI：
10.3847/0067-0049/225/2/26
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发表时间：
2016-08
期刊：
影响因子：
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通讯作者：
Mi-Ryang Kim;C. Lee;M. Dunham;N. Evans II;Gwanjeong Kim;L. Allen
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文献类型：
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作者：
Mi-Ryang Kim;C. Lee;M. Dunham;N. Evans II;Gwanjeong Kim;L. Allen
本文介绍了利用1.25 ~ 850 μm的红外和亚毫米（sub-mm）数据以及我们的（J = 1−0）观测在古尔德带（GB）云中搜索极低光度天体（VeLLO）的结果。我们修改了Dunham等人的标准，以选择GB云中的VeLLO，发现了95个VeLLO候选者，其中79个是本研究中新发现的。在95个源中，44个在亚毫米连续区和发射区都被检测到，并被归类为A组（VeLLO），51个在亚毫米发射区或发射区被检测到的源被归类为B组候选VeLLO。我们发现，这些VeLLO和候选人是在不同的环境中形成的可能VeLLO。78个源嵌入其分子云中，因此可能是在稠密环境中形成的VeLLO。其余17个源位于低水平消光区（）连接到云，可以是背景源或候选的亚恒星物体形成在一个孤立的模式。VeLLO和候选者可能更明亮，它们的包络在密度更大的环境中往往更大。VeLLO和候选者在形成更多YSO的云中人口更多，表明它们以类似于正常YSO的方式形成。的VeLLOs的辐射热光度和温度进行了比较，预测的情节吸积模型，表明低光度的大多数VeLLOs可以很好地解释他们的状态在静止阶段的一个周期的情节质量吸积。
We present the results of a search for Very Low-Luminosity Objects (VeLLOs) in the Gould Belt (GB) clouds using infrared and sub-millimeter (sub-mm) data from 1.25 to 850 μm and our (J = 1−0) observations. We modified the criteria by Dunham et al. to select the VeLLOs in the GB clouds, finding 95 VeLLO candidates, 79 of which are newly identified in this study. Out of 95 sources, 44 were detected in both sub-mm continuum and emission and were classified as Group A (the VeLLOs), and 51 sources detected in either sub-mm emission or emission were classified with Group B as candidate VeLLOs. We find that these VeLLOs and the candidates are forming in environments different from those of the likely VeLLOs. Seventy-eight sources are embedded within their molecular clouds, and thus are likely VeLLOs forming in a dense environment. The remaining 17 sources are located in low-level extinction regions ( ) connected to the clouds, and can be either background sources or candidate substellar objects forming in an isolated mode. The VeLLOs and the candidates are likely more luminous and their envelopes tend to be more massive in denser environments. The VeLLOs and the candidates are more populous in the clouds where more YSOs form, indicating that they form in a manner similar to that of normal YSOs. The bolometric luminosities and temperatures of the VeLLOs are compared to predictions of episodic accretion models, showing that the low luminosities for most VeLLOs can be well explained by their status in the quiescent phases of a cycle of episodic mass accretion.