DUST IN THE INNER REGIONS OF DEBRIS DISKS AROUND A STARS
DUST IN THE INNER REGIONS OF DEBRIS DISKS AROUND A STARS
复制标题
恒星周围碎片盘内部区域的尘埃
DOI：
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发表时间：
2008
期刊：
影响因子：
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通讯作者：
N. Turner
中科院分区：
文献类型：
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作者：
R. Akeson;D. Ciardi;R. Millan;A. Mérand;E. D. Folco;J. D. Monnier;C. Beichman;O. Absil;J. Aufdenberg;H. Mcalister;T. Brummelaar;J. Sturmann;L. Sturmann;N. Turner
我们利用CHARA干涉仪上的FLUOR仪器在短（30米）和长（> 200米）基线上对两个A星碎片盘β Leo和β Lep的内部区域进行了红外干涉观测。对于靶星，短基线的视亮度比单独的恒星光球的视亮度要低，而校验星星，δ Leo的视亮度则不低。我们解释这个可见度偏移的百分之几的近红外（NIR）过剩所产生的尘埃颗粒，由于仪器的视野，必须位于几个Au的中央星星。对于β Leo，产生近红外过量的颗粒在空间上与产生先前已知的中红外（MIR）过量的尘埃不同。对于NIPLEP，NIR过量可能与MIR过量产生材料在空间上相关联。我们提出了简单的几何模型，这是一致的近红外和MIR的过剩，并表明，对于这两个对象，近红外生产材料是最一致的薄环附近的尘埃升华半径，典型的晶粒尺寸小于标称辐射压力井喷半径。最后，我们讨论了可能的起源的近红外辐射尘埃的背景下，碎片盘的演变模型。
We present infrared interferometric observations of the inner regions of two A-star debris disks, β Leo and ζ Lep, using the FLUOR instrument at the CHARA interferometer on both short (30 m) and long (> 200 m) baselines. For the target stars, the short-baseline visibilities are lower than expected for the stellar photosphere alone, while those of a check star, δ Leo, are not. We interpret this visibility offset of a few percent as a near-infrared (NIR) excess arising from dust grains which, due to the instrumental field of view, must be located within several AU of the central star. For β Leo, the NIR excess-producing grains are spatially distinct from the dust which produces the previously known mid-infrared (MIR) excess. For ζ Lep, the NIR excess may be spatially associated with the MIR excess-producing material. We present simple geometric models which are consistent with the NIR and MIR excesses and show that for both objects, the NIR-producing material is most consistent with a thin ring of dust near the sublimation radius, with typical grain sizes smaller than the nominal radiation pressure blowout radius. Finally, we discuss possible origins of the NIR-emitting dust in the context of debris disk evolution models.