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arXiv 1308.6000astro-ph.SR
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HD 85567:一颗Herbig B[e]星或一颗相互作用的B[e]双星

HD 85567: A Herbig B[e] star or an interacting B[e] binary

H. E. Wheelwright, G. Weigelt, A. Caratti o Garatti, R. Garcia Lopez

摘要:

上下文HD 85567是一个神秘的天体,表现出B[e]现象,即在光学上有红外过量和禁止的发射线。这个天体的演化状态是不确定的,有相互矛盾的说法,认为它是一个年轻的恒星天体,还是一个演化的相互作用的双星。目标。为了阐明HD 85567的B[e]行为的原因,我们用VLTI和AMBER观察了它。方法.我们的观测是在K波段进行的,具有中等光谱分辨率(R~1500,即200 km/s)。HD 85567的光谱显示出Br γ和CO泛音带头发射。获得的干涉数据包括光谱分散的vibrium,封闭阶段和微分阶段,这些光谱特征和K波段连续。结果闭合阶段的观察结果没有显示不对称的证据。HD 85567在K波段的表观大小是通过用环模型拟合vibrant来确定的。最佳拟合半径为0.8 +/- 0.3 AU,相对较小,使得HD 85567与基于低光度和中等光度的YSO的大小-光度关系相比显得过小。先前已经发现这是发光YSO的情况,并且已经提出这是由于光学厚的气体盘的存在。我们表明,微分相位观测CO带头发射确实是一致的存在下,一个紧凑的(~1 AU)的气体盘内部的尘埃升华半径。结论.观察结果显示没有二元性的迹象。然而,这些数据确实表明尘埃升华半径内部存在气体盘。我们的结论是,数据是一致的假设,HD 85567是一个YSO与光学厚的气体盘内的一个较大的尘埃盘,是从外缘光蒸发。

英文摘要:

Context. HD 85567 is an enigmatic object exhibiting the B[e] phenomenon, i.e. an infrared excess and forbidden emission lines in the optical. The object's evolutionary status is uncertain and there are conflicting claims that it is either a young stellar object or an evolved, interacting binary. Aims. To elucidate the reason for the B[e] behaviour of HD 85567, we have observed it with the VLTI and AMBER. Methods. Our observations were conducted in the K-band with moderate spectral resolution (R~1500, i.e. 200 km/s). The spectrum of HD 85567 exhibits Br gamma and CO overtone bandhead emission. The interferometric data obtained consist of spectrally dispersed visibilities, closure phases and differential phases across these spectral features and the K-band continuum. Results. The closure phase observations do not reveal evidence of asymmetry. The apparent size of HD 85567 in the K-band was determined by fitting the visibilities with a ring model. The best fitting radius, 0.8 +/- 0.3 AU, is relatively small making HD 85567 undersized in comparison to the size-luminosity relationship based on YSOs of low and intermediate luminosity. This has previously been found to be the case for luminous YSOs, and it has been proposed that this is due to the presence of an optically thick gaseous disc. We demonstrate that the differential phase observations over the CO bandhead emission are indeed consistent with the presence of a compact (~1 AU) gaseous disc interior to the dust sublimation radius. Conclusions. The observations reveal no sign of binarity. However, the data do indicate the presence of a gaseous disc interior to the dust sublimation radius. We conclude that the data are consistent with the hypothesis that HD 85567 is a YSO with an optically thick gaseous disc within a larger dust disc that is being photo-evaporated from the outer edge.

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