AN INTERFEROMETRIC STUDY OF THE FOMALHAUT INNER DEBRIS DISK. I. NEAR-INFRARED DETECTION OF HOT DUST WITH VLTI/VINCI
AN INTERFEROMETRIC STUDY OF THE FOMALHAUT INNER DEBRIS DISK. I. NEAR-INFRARED DETECTION OF HOT DUST WITH VLTI/VINCI
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对北落师门内碎片盘的干涉研究。
DOI：
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发表时间：
2009
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通讯作者：
J. Augereau
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作者：
O. Absil;B. Mennesson;J. Le Bouquin;E. di Folco;P. Kervella;J. Augereau
由于与母星的高对比度和小角度间隔，围绕主序星的尘埃碎片盘的最里面部分目前鲜为人知。利用近红外干涉测量学，我们的目标是探测附近A4V恒星北落师门周围的热尘埃的特征，这颗恒星已经被认为除了位于大约140AU的冷尘埃环之外，还有一个温暖尘埃种群。使用VLTI的VINCI仪器获得的档案数据用于研究在K波段的投影基线长度从4米到140米范围内的Fomalhaut系统的条纹能见度。相对于唯一恒星光球层的预期能见度，在短基线上观察到明显的能见度不足。这被解释为分解的恒星周围发射的信号，产生相对于恒星光球层的0.88%±0.12%的相对通量。虽然我们的干涉测量数据不能直接限制过量发射源的形态，但来自文献的补充数据允许我们丢弃离轴点状天体作为星周发射源。我们认为，位于北落科6AU范围内的热尘埃颗粒的热发射是对探测到的过剩的最合理的解释。我们的研究还提供了一个修正的北落总科的肢体暗化直径(θLD=2.223±0.022马斯)，考虑了分辨的星周辐射的影响。
The innermost parts of dusty debris disks around main-sequence stars are currently poorly known due to the high contrast and small angular separation with their parent stars. Using near-infrared interferometry, we aim to detect the signature of hot dust around the nearby A4 V star Fomalhaut, which has already been suggested to harbor a warm dust population in addition to a cold dust ring located at about 140 AU. Archival data obtained with the VINCI instrument at the VLTI are used to study the fringe visibility of the Fomalhaut system at projected baseline lengths ranging from 4 m to 140 m in the K band. A significant visibility deficit is observed at short baselines with respect to the expected visibility of the sole stellar photosphere. This is interpreted as the signature of resolved circumstellar emission, producing a relative flux of 0.88% ± 0.12% with respect to the stellar photosphere. While our interferometric data cannot directly constrain the morphology of the excess emission source, complementary data from the literature allow us to discard an off-axis point-like object as the source of circumstellar emission. We argue that the thermal emission from hot dusty grains located within 6 AU from Fomalhaut is the most plausible explanation for the detected excess. Our study also provides a revised limb-darkened diameter for Fomalhaut (θLD = 2.223 ± 0.022 mas), taking into account the effect of the resolved circumstellar emission.