Angular diameter measurements of cool giant stars in strong TiO bands and in the continuum
Angular diameter measurements of cool giant stars in strong TiO bands and in the continuum
复制标题
强 TiO2 能带和连续谱中冷巨星的角直径测量
DOI：
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发表时间：
1993
期刊：
影响因子：
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通讯作者：
C. Hummel
中科院分区：
文献类型：
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作者：
A. Quirrenbach;D. Mozurkewich;J. Armstrong;D. Buscher;C. Hummel
我们目前的角直径测量的15个巨星和超巨星的强TiO吸收带在712 nm和连续带在754 nm的MKIII长基线干涉仪。虽然相对温暖的巨星（光谱类型K5 III或M0 III）在两种滤光镜下测量的直径相同，但较冷的恒星（光谱类型M3 III至M5 III）在712 nm处的直径比754 nm处大10%。这种效应在光度I类恒星中更为明显。可以通过注意到冷恒星的稀薄和扩展的恒星大气在TiO吸收带中变得不透明来理解，TiO吸收带的半径明显大于连续谱;即，我们直接测量恒星大气层的物理范围
We present angular diameter measurements of 15 giant and supergiant stars in the strong TiO absorption band at 712 nm and in a continuum band at 754 nm with the MkIII long-baseline interferometer. While relatively warm giant stars (spectral types K5 III or M0 III) have identical diameters measured with the two filters, cooler stars (spectral types M3 III to M5 III) appear ∼10% larger at 712 nm than at 754 nm. This effect is even more pronounced in luminosity class I stars. It can be understood by noting that the tenuous and extended stellar atmospheres of cool stars become opaque in TiO absorption bands at a significantly larger radius than in the continuum; i.e., we measure directly the physical extension of the stellar atmospheres