Warm gas towards young stellar objects in Corona Australis - Herschel/PACS observations from the DIGIT key programme
Warm gas towards young stellar objects in Corona Australis - Herschel/PACS observations from the DIGIT key programme
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温暖的气体流向澳大利亚日冕的年轻恒星 - 来自 DIGIT key 计划的 Herschel/PACS 观测
DOI：
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
S. Wampfler
中科院分区：
文献类型：
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作者：
J. Lindberg;J. Jørgensen;Joel D. Green;G. Herczeg;O. Dionatos;N. Evans;A. Karska;S. Wampfler
外界辐射对低质量年轻恒星周围原恒星包层中化学和物理的影响还知之甚少。南冕恒星形成区包含R CRA暗云，它由几个受到中等质量年轻恒星照射的低质量原恒星核心组成。研究了年轻发光的HerBig Be星RCRA对一组小质量年轻星体中的热气体和尘埃的影响。给出了RCRA暗云中两个低质量恒星形成区的Herschel/PACS远红外数据立方体。研究了CO、OH、H2O、[C II]、[O I]和连续发射的分布。我们开发了一种去卷积算法，用于对地图进行去卷积，将点源发射与扩展发射分开。我们还构建了分子物种的旋转图。通过对赫歇尔数据的反褶积，我们发现了与点源无关的大尺度(几千AU)尘埃连续谱和谱线发射。在点源和扩展排放中，暖CO($282pm4$K)、热CO($890pm84$K)、OH($79pm4$K)和H2O($197pm7$K)排放的旋转温度相似。旋转温度也类似于在其他更孤立的核心中发现的温度。在两个脊线上发现了扩展的尘埃连续发射，其范围和温度与分子毫米发射相似，表明赫比格Be星RCRA的外部加热。我们的结果表明，附近的一颗发光恒星并不会增加年轻恒星(YSO)周围温暖气体中的分子激发温度。然而，与没有受到外部照射的类似物体相比，在与这些原恒星及其周围相关的温暖气体中，H2O的光解产物(如OH和O)的发射增强。
The effects of external irradiation on the chemistry and physics in the protostellar envelope around low-mass young stellar objects are poorly understood. The Corona Australis star-forming region contains the R CrA dark cloud, comprising several low-mass protostellar cores irradiated by an intermediate-mass young star. We study the effects on the warm gas and dust in a group of low-mass young stellar objects from the irradiation by the young luminous Herbig Be star R CrA. Herschel/PACS far-infrared datacubes of two low-mass star-forming regions in the R CrA dark cloud are presented. The distribution of CO, OH, H2O, [C II], [O I], and continuum emission is investigated. We have developed a deconvolution algorithm which we use to deconvolve the maps, separating the point-source emission from the extended emission. We also construct rotational diagrams of the molecular species. By deconvolution of the Herschel data, we find large-scale (several thousand AU) dust continuum and spectral line emission not associated with the point sources. Similar rotational temperatures are found for the warm CO ($282pm4$ K), hot CO ($890pm84$ K), OH ($79pm4$ K), and H2O ($197pm7$ K) emission, respectively, in the point sources and the extended emission. The rotational temperatures are also similar to what is found in other more isolated cores. The extended dust continuum emission is found in two ridges similar in extent and temperature to molecular mm emission, indicative of external heating from the Herbig Be star R CrA. Our results show that a nearby luminous star does not increase the molecular excitation temperatures in the warm gas around a young stellar object (YSO). However, the emission from photodissociation products of H2O, such as OH and O, is enhanced in the warm gas associated with these protostars and their surroundings compared to similar objects not suffering from external irradiation.
影响因子：
6.5
作者：
A. Sicilia-Aguilar;T. Henning;H. Linz;P. Andre';A. Stutz;C. Eiroa;G. White
通讯作者：
A. Sicilia-Aguilar;T. Henning;H. Linz;P. Andre';A. Stutz;C. Eiroa;G. White