Multiwavelength modelling of the β Leo debris disc: one, two or three planetesimal populations?
Multiwavelength modelling of the β Leo debris disc: one, two or three planetesimal populations?
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β狮子座碎片盘的多波长建模：一个、两个或三个星子群？
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发表时间：
2011
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通讯作者：
G. Rieke
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作者：
L. Churcher;M. Wyatt;G. Duchêne;B. Sibthorpe;G. Kennedy;B. Matthews;P. Kalas;J. Greaves;K. Su;G. Rieke
在本文中，我们提出了 β Leo 碎片盘的模型，重点是对作为赫歇尔关键程序 DEBRIS 的一部分获得的解析光电探测器阵列相机和光谱仪 (PACS) 图像进行建模。我们还展示了 250 μm 光盘的新光谱和光度成像接收器 (SPIRE) 图像，以及 SCUBA-2、中红外 (mid-IR) 和散射光成像对光盘的新限制。结合所有可用的观测限制，我们找到了 β Leo (HD 102647) 碎片盘的三种可能的模型： (i) 双成分模型，由 2 个天文单位的热成分和 15 至 70 个天文单位的冷成分组成； (ii) 三分量模型具有 2 个天文单位的热尘埃、9 个天文单位的暖尘埃和 30 至 70 个天文单位的冷分量，同样有效，因为冷发射在 30 个天文单位内未得到解决； (iii) 一种不太可能的可能性是，该系统由一个非常偏心的星子群组成，其近心在 2 个天文单位，远心在 65 个天文单位。因此，尽管存在大量的观测限制，但仍然存在很大的模糊性。 30 au 范围内灰尘分布的深中红外和散射光成像似乎是解决简并性的最有希望的方法。我们讨论对可能的行星系统架构的影响，例如二分量模型认为2-15个天文单位可能存在行星，而三分量模型则认为2-30个天文单位之间存在行星，并具有包含9个天文单位尘埃带的稳定区域，而偏心星子模型中不应存在2-65个天文单位之间的行星。我们认为热尘埃可能起源于分散在冷盘中的彗星的解体，并检查了所有已知含有热尘埃和冷尘埃的 A 星，以考虑热尘埃和冷尘埃的光度之比是否表明了介入的行星系统结构。
In this paper we present a model of the β Leo debris disc, with an emphasis on modelling the resolved Photodetector Array Camera and Spectrometer (PACS) images obtained as a part of the Herschel key programme DEBRIS. We also present new Spectral and Photometric Imaging REceiver (SPIRE) images of the disc at 250 μm, as well as new constraints on the disc from SCUBA-2, mid-infrared (mid-IR) and scattered light imaging. Combining all the available observational constraints, we find three possible models for the β Leo (HD 102647) debris disc: (i) a two-component model, comprised of a hot component at 2 au and a cold component from 15 to 70 au; (ii) a three-component model with hot dust at 2 au, warm dust at 9 au and a cold component from 30 to 70 au, is equally valid since the cold emission is not resolved within 30 au; (iii) a somewhat less likely possibility is that the system consists of a single very eccentric planetesimal population, with pericentres at 2 au and apocentres at 65 au. Thus, despite the wealth of observational constraints significant ambiguities remain; deep mid-IR and scattered light imaging of the dust distribution within 30 au seems to be the most promising method to resolve the degeneracy. We discuss the implications for the possible planetary system architecture, e.g. the two-component model suggests that planets may exist at 2–15 au, while the three-component model suggests planets between 2 and 30 au with a stable region containing the dust belt at 9 au, and there should be no planets between 2 and 65 au in the eccentric planetesimal model. We suggest that the hot dust may originate in the disintegration of comets scattered in the cold disc, and examine all A stars known to harbour both hot and cold dust to consider the possibility that the ratio of hot and cold dust luminosities is indicative of the intervening planetary system architecture.