Millimeter-Wave Aperture Synthesis Imaging of Vega: Evidence for a Ring Arc at 95 AU
Millimeter-Wave Aperture Synthesis Imaging of Vega: Evidence for a Ring Arc at 95 AU
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Vega 的毫米波孔径合成成像：95 天文单位环弧的证据
DOI：
10.1086/324226
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发表时间：
2001
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影响因子：
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通讯作者：
N. Ostroff
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作者：
D. Koerner;A. Sargent;N. Ostroff
我们给出了第一张主序星周围尘埃的毫米波口径合成图。织女星1.3毫米连续发射的3英寸分辨率图像显示了恒星在一个位置角(P.A.)处发出的12“”辐射束。45°，与较低分辨率的James Clerk Maxwell望远镜/亚毫米共用测辐射阵列(SCUBA)地图上最大发射850μm的位置一致。磁通密度为4.0±0.9mJy。相邻的1.3 mm的峰通量密度分别为3.4±1.0mJy和2.8±0.9mJy，它们分别位于距离S恒星67°和18°的14“和13”处，最强的两个峰之间有一座弧形的桥相连，在西南方向还有一个2.4±0.8mJy的峰，这与光球层的发射是一致的。从850μm通量的外推，假设F1.3-0.85 mm∝λ-2.8，与织女星1.3 mm的总探测通量很好地吻合，并暗示尘埃发射率指数β为0.8。我们得出结论，我们在口径合成地图上探测到了Scuba成像的所有尘埃，除了非常小的一部分，这些颗粒主要局限在半径为95AU的环的部分。
We present the first millimeter-wave aperture synthesis map of dust around a main-sequence star. A 3'' resolution image of 1.3 mm continuum emission from Vega reveals a clump of emission 12'' from the star at a position angle (P.A.) of 45°, consistent with the location of maximum 850 μm emission in a lower resolution James Clerk Maxwell Telescope/Submillimeter Common-User Bolometric Array (SCUBA) map. The flux density is 4.0 ± 0.9 mJy. Adjacent 1.3 mm peaks with flux densities of 3.4 ± 1.0 and 2.8 ± 0.9 mJy are located 14'' and 13'' from the star at P.A.'s of 67° and 18°, respectively. An arclike bridge connects the two strongest peaks. There is an additional 2.4 ± 0.8 mJy peak to the southwest, 11'' from the star at P.A. = 215°, and a marginal detection, 1.4 ± 0.5 mJy, at the stellar position, consistent with photospheric emission. An extrapolation from the 850 μm flux, assuming F1.3-0.85 mm ∝ λ-2.8, agrees well with the total detected flux for Vega at 1.3 mm and implies a dust emissivity index β of 0.8 We conclude that we have detected all but a very small fraction of the dust imaged by SCUBA in our aperture synthesis map and that these grains are largely confined to segments of a ring of radius 95 AU.
伦敦大学学院大盾空间科学实验室/爱丁堡大学（英国）
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