New views of Betelgeuse: multi‐wavelength surface imaging and implications for models of hotspot generation
New views of Betelgeuse: multi‐wavelength surface imaging and implications for models of hotspot generation
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参宿四的新观点：多波长表面成像及其对热点生成模型的影响
DOI：
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发表时间：
2000
期刊：
影响因子：
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通讯作者：
R. Wilson
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文献类型：
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作者：
J. Young;J. Baldwin;Roger C. Boysen;C. Haniff;P. Lawson;C. Mackay;D. Pearson;J. Rogers;D. St;P. Warner;D. Wilson;R. Wilson
摘要 我们报告了使用剑桥光学孔径合成望远镜 (COAST) 和威廉·赫歇尔望远镜 (WHT) 在 700、905 和 1290 nm 波长下对红超巨星参宿四 (猎户座) 进行的同期多波长干涉成像。我们发现恒星亮度分布的表观对称性作为波长的函数存在很大的变化。在 700 nm 处，恒星是高度不对称的，可以将其建模为三个亮点在边缘黑暗的圆盘上的叠加。然而，在 905 nm 处，仅可见单个低对比度特征，而在 1290 nm 处，恒星呈现出无特征的对称圆盘。光斑对比度随波长的变化与一个模型一致，其中亮点代表恒星盘上不被遮挡的高温区域（可能是由于对流），该恒星盘本身在不同波长下具有不同的外观，即几何范围和临边变暗轮廓。在 1290 nm 处看到的无特征的中心到边缘的亮度分布与该模型一致，并表明未来应该在近红外的类似波长下对恒星进行干涉监测，以量化与径向速度变化相关的尺寸变化。
ABSTRA C T We report contemporaneous multi-wavelength interferometric imaging of the red supergiant star Betelgeuse (a Orionis), using the Cambridge Optical Aperture Synthesis Telescope (COAST) and the William Herschel Telescope (WHT), at wavelengths of 700, 905 and 1290 nm. We find a strong variation in the apparent symmetry of the stellar brightness distribution as a function of wavelength. At 700 nm the star is highly asymmetric, and can be modelled as the superposition of three bright spots on a strongly limb-darkened disc. However, at 905 nm only a single low-contrast feature is visible and at 1290 nm the star presents a featureless symmetric disc. The change in spot contrast with wavelength is consistent with a model in which the bright spots represent unobscured areas of elevated temperature, owing perhaps to convection, on a stellar disc that itself has a different appearance, i.e. geometrical extent and limb-darkening profile, at different wavelengths. The featureless centre-to-limb brightness profile seen at 1290 nm is consistent with this model and suggests that future interferometric monitoring of the star to quantify the size changes associated with radial velocity variations should be performed at similar wavelengths in the near-infrared.