Determination of the far-infrared dust opacity in a prestellar core
Determination of the far-infrared dust opacity in a prestellar core
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星际核心中远红外尘埃不透明度的测定
DOI：
10.1051/0004-6361/201219103
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发表时间：
2013
影响因子：
6.5
通讯作者：
Suutarinen A
中科院分区：
文献类型：
--
作者：
Suutarinen A
从远红外和亚毫米映射星际云的质量估计取决于假设的尘埃吸收截面在这些波长的辐射aimsThe的目的是确定远红外尘埃吸收截面在一个无星，密集的核心位于南冕。该值是确定堆芯质量和其他物理性质所必需的。它也可以有一个轴承上的演化stage of the core.MethodsWe相关的近红外stellarH− Kavalour过剩的背景恒星从NTT/SOFI与远红外光学深度图，τFIR，来自Herschel 160，250，350，和500μm的数据。TheHerschelmaps也被用来构建一个模型的云来研究温度梯度的影响上估计的光学厚度和尘埃absorption cross-sections.ResultsA的线性相关性之间的颜色H −KsandτFIRup到高折射率（AV~ 25）。假设标准近红外消光定律和尘埃发射率指数β= 2，则相关性转化为平均消光比A250 μm/AJ= 0.0014 ± 0.0002。用NH/A_J比值计算得到每个H原子核的平均吸收截面σ H_（250）μm=（1.8 ± 0.3）× 10 ~（-25）cm H原子，相当于单位质量气体的吸收截面κ H_（250）μ m = 0.08 ± 0.01 cm g。然而，云模型表明，由于沿着视线的温度变化引起的偏差，这些值低估了核心中心附近的真实横截面高达40%。假设该模型正确地描述了温度变化对τ FIR的影响，我们发现H-K和τ FIR之间的关系与最近确定的猎户座A中σ和NH之间的关系一致。结论导出的远红外截面与先前在中等柱密度分子云中的测定结果一致，并且与其他一些冷核相比并不是特别大。我们认为这与核心不是很致密（中心密度可能是~ 105 cm）有关，并且从以前的分子线数据判断，它似乎处于化学演化的早期阶段。
ContextMass estimates of interstellar clouds from far-infrared and submillimetre mappings depend on the assumed dust absorption cross-section for radiation at those wavelengths.AimsThe aim is to determine the far-IR dust absorption cross-section in a starless, dense core located in Corona Australis. The value is needed for determining of the core mass and other physical properties. It can also have a bearing on the evolutionary stage of the core.MethodsWe correlated near-infrared stellarH−Kscolour excesses of background stars from NTT/SOFI with the far-IR optical depth map,τFIR, derived fromHerschel160, 250, 350, and 500μm data. TheHerschelmaps were also used to construct a model for the cloud to examine the effect of temperature gradients on the estimated optical depths and dust absorption cross-sections.ResultsA linear correlation is seen between the colourH−KsandτFIRup to high extinctions (AV~ 25). The correlation translates to the average extinction ratioA250μm/AJ= 0.0014 ± 0.0002, assuming a standard near-infrared extinction law and a dust emissivity indexβ= 2. Using an empiricalNH/AJratio we obtain an average absorption cross-section per H nucleus of σH250 μm= (1.8 ± 0.3) × 10-25cm H-atom, corresponding to a cross-section per unit mass of gas κ250 μmg= 0.08 ± 0.01 cm g. The cloud model, however, suggests that owing to the bias caused by temperature changes along the line-of-sight, these values underestimate the true cross-sections by up to 40% near the centre of the core. Assuming that the model describes the effect of the temperature variation onτFIRcorrectly, we find that the relationship betweenH−KsandτFIRagrees with the recently determined relationship betweenσHandNHin Orion A.ConclusionsThe derived far-IR cross-section agrees with previous determinations in molecular clouds with moderate column densities, and is not particularly large compared with some other cold cores. We suggest that this is connected to the core not being very dense (the central density is likely to be ~105cm), and judging from previous molecular line data, it appears to be at an early stage of chemical evolution.
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影响因子：
6.5
作者：
N. Ysard;M. Juvela;K. Demyk;V. Guillet;A. Abergel;J. Bernard;J. Malinen;C. M'eny;L. Montier;D. Paradis;I. Ristorcelli;L. Verstraete
通讯作者：
N. Ysard;M. Juvela;K. Demyk;V. Guillet;A. Abergel;J. Bernard;J. Malinen;C. M'eny;L. Montier;D. Paradis;I. Ristorcelli;L. Verstraete
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影响因子：
6.5
作者：
C. Kramer;J. Richer;B. Mookerjea;J. Alves;C. Lada
通讯作者：
C. Lada
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影响因子：
6.5
作者：
D. Paradis;J. Bernard;C. Meny
通讯作者：
C. Meny
猎户座分子云中尘埃不透明度随密度的变化
DOI：
--
发表时间：
2012
期刊：
影响因子：
--
作者：
A. Roy;P. Martin;D. Polychroni;S. Bontemps;A. Abergel;P. Andre';D. Arzoumanian;J. di Francesco;T. Hill;V. Konyves;Q. Nguyen;S. Pezzuto;N. Schneider;L. Testi;G. White
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G. White
亚毫米级尘埃不透明度的环境变化证据
DOI：
--
发表时间：
2011
期刊：
影响因子：
--
作者：
P. Martin;A. Roy;S. Bontemps;M. Miville;P. Ade;J. Bock;E. Chapin;M. Devlin;S. Dicker;M. Griffin;J. Gundersen;M. Halpern;P. Hargrave;D. Hughes;J. Klein;G. Marsden;P. Mauskopf;C. Netterfield;L. Olmi;G. Patanchon;M. Rex;D. Scott;C. Semisch;M. Truch;C. Tucker;G. Tucker;M. Viero;D. Wiebe
通讯作者：
D. Wiebe