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arXiv 0906.1145astro-ph.SR
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F型恒星周围新的温暖碎片盘的发现

The discovery of new warm debris disks around F-type stars

A. Moór, D. Apai, I. Pascucci, P. Ábrahám, C. Grady, Th. Henning, A. Juhász, Cs. Kiss, Á. Kóspál

摘要:

我们报告发现了四个罕见的碎片盘,在F星周围存在过度温暖的现象,显着增加了太阳附近已知的此类系统的数量。其中三个盘与稳态星子盘演化模型的预测一致。最古老的源,HD 169666,显示尘埃光度分数太高,是在稳定状态,我们认为,这个系统最近经历了一个短暂的事件的尘埃生产。此外,这颗恒星的两个光谱相隔约三年,显示出硅酸盐的发射特征,表明亚微米至微米尺寸的颗粒。我们认为,这样的小颗粒会迅速耗尽,它们在两个光谱中的存在表明,小尘埃的生产是连续的,至少在几年的时间尺度。我们预测,系统显示可变的中红外光谱,如果存在的话,将提供有价值的帮助,在区分可能的情况下提出的灰尘补充。

英文摘要:

We report the discovery of four rare debris disks with warm excesses around F-stars, significantly increasing the number of such systems known in the solar neighborhood. Three of the disks are consistent with the predictions of steady state planetesimal disk evolution models. The oldest source, HD 169666, displays a dust fractional luminosity too high to be in steady state and we suggest that this system recently underwent a transient event of dust production. In addition, two spectra of this star separated by ~three years show silicate emission features, indicative of submicron- to micron-sized grains. We argue that such small grains would be rapidly depleted and their presence in both spectra suggests that the production of small dust is continuous over at least on few years timescale. We predict that systems showing variable mid-infrared spectra, if exist, will provide valuable help in distinguishing the possible scenarios proposed for dust replenishment.

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