A peculiar class of debris disks from Herschel /DUNES
A peculiar class of debris disks from Herschel /DUNES
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Herschel/DUNES 中一类特殊的碎片盘
DOI：
10.1051/0004-6361/201118077
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
J.-C. Augereau
中科院分区：
文献类型：
--
作者：
S. Ertel;S. Wolf;J.P. Marshall;C. Eiroa;J.-C. Augereau
HIP 103389(HD 199260)、HIP 107350(HN Peg，HD 206860)和HIP 114948(HD 219482)周围的碎片盘的光度学数据，这些数据是在我们的HerschelOpen Time Key程序沙丘(附近恒星周围的尘埃)的背景下获得的。方法我们使用Herschel/PACS探测这三个碎片盘的热发射，在100σm和160μm的3μ灵敏度为几mJ。此外，我们还获得了70μm的HIP 103389的光度数据。这些观测得到了大量从光学到远红外的光度学数据的补充。采用两种不同的方法对Herschel数据进行约简，以考察数据约简对光度学的影响。利用模拟热退火法和经典的网格搜索法将分析模型与可用光谱能量分布数据进行拟合。结果这三个圆盘的可用光谱能量分布在≥70μm处可能呈现异常陡峭的衰减。我们研究了这些可用光谱能量分布的特殊形状的意义及其对圆盘模型的影响，前提是它是真实的。使用已经被成功应用于许多其他碎片盘模拟的颗粒组成，我们的模拟显示，在长波区域SED的如此急剧的下降与标准平衡碰撞级联所期望的−3.5的颗粒尺寸分布的幂指数不一致。相反，一个陡峭的颗粒尺寸分布，或者，替代地，在几十微米范围内的较高颗粒尺寸是隐含的。这表明，一系列非常不同的颗粒尺寸将主导这类圆盘的热发射。然而，我们证明，对Herschel获得的弱源数据的理解仍然不完整，我们结果的重要性取决于所使用的数据还原管道的版本。结论需要一种新的机制来产生碎片盘中的尘埃，偏离标准平衡碰撞级联所需的条件(粒度指数为−3.5)，和/或显著不同的尘埃性质，以解释所提供的三个碎片盘潜在陡峭的SED形状。
ContextThe existence of debris disks around old main sequence stars is usually explained by continuous replenishment of small dust grains through collisions from a reservoir of larger objects.AimsWe present photometric data of debris disks around HIP 103389 (HD 199260), HIP 107350 (HN Peg, HD 206860), and HIP 114948 (HD 219482), obtained in the context of ourHerschelopen time key program DUNES (DUst around NEarby Stars).MethodsWe usedHerschel/PACS to detect the thermal emission of the three debris disks with a 3σsensitivity of a few mJy at 100μm and 160μm. In addition, we obtainedHerschel/PACS photometric data at 70μm for HIP 103389. These observations are complemented by a large variety of optical to far-infrared photometric data. Two different approaches are applied to reduce theHerscheldata to investigate the impact of data reduction on the photometry. We fit analytical models to the available spectral energy distribution (SED) data using the fitting method of simulated thermal annealing as well as a classical grid search method.ResultsThe SEDs of the three disks potentially exhibit an unusually steep decrease at wavelengths ≥70μm. We investigate the significance of the peculiar shape of these SEDs and the impact on models of the disks provided it is real. Using grain compositions that have been applied successfully for modeling of many other debris disks, our modeling reveals that such a steep decrease of the SEDs in the long wavelength regime is inconsistent with a power-law exponent of the grain size distribution −3.5 expected from a standard equilibrium collisional cascade. In contrast, a steep grain size distribution or, alternatively an upper grain size in the range of few tens of micrometers are implied. This suggests that a very distinct range of grain sizes would dominate the thermal emission of such disks. However, we demonstrate that the understanding of the data of faint sources obtained withHerschelis still incomplete and that the significance of our results depends on the version of the data reduction pipeline used.ConclusionsA new mechanism to produce the dust in the presented debris disks, deviations from the conditions required for a standard equilibrium collisional cascade (grain size exponent of −3.5), and/or significantly different dust properties would be necessary to explain the potentially steep SED shape of the three debris disks presented.
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DOI：
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发表时间：
2010
期刊：
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发表时间：
2004
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作者：
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DOI：
10.1017/s1743921309031950
发表时间：
2008
期刊：
Proceedings of the International Astronomical Union
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作者：
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DOI：
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发表时间：
2007
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作者：
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J. Bouwman