Crystalline Silicate Feature of the Vega-like Star HD 145263
Crystalline Silicate Feature of the Vega-like Star HD 145263
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DOI：
10.1086/423242
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发表时间：
2004-06
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通讯作者：
M. Honda;H. Kataza;Y. Okamoto;T. Miyata;T. Yamashita;S. Sako;T. Fujiyoshi;Meguru Ito;Y. Okada;I. Sakon;T. Onaka
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作者：
M. Honda;H. Kataza;Y. Okamoto;T. Miyata;T. Yamashita;S. Sako;T. Fujiyoshi;Meguru Ito;Y. Okada;I. Sakon;T. Onaka
利用Subaru/COMICS观测了类织女星星星候选星HD 145263的8-13 μm光谱（R ~ 250）。HD 145263的光谱显示宽梯形硅酸盐特征，肩部位于9.3和11.44 μm处，表明存在结晶硅酸盐颗粒。这一发现意味着结晶硅酸盐也可能普遍存在于类似织女星的恒星周围。与赫比格Ae/Be星和金牛座T星的11.2-3 μm晶体镁橄榄石特征相比，11.44 μm的特征稍微向更长的波长移动。虽然不能排除由于晶粒尺寸的影响的峰位移，我们建议，含铁结晶橄榄石解释所观察到的峰值波长相当不错。含铁硅酸盐通常存在于陨石和大多数行星际尘埃颗粒中，这些尘埃颗粒起源于类行星小行星。根据对陨石的研究，含铁硅酸盐一定是在小行星中形成的，如果观测到的11.44 μm峰值是由含铁硅酸盐造成的，那么支持了类织女星周围的尘埃颗粒来自小行星的假设。
We have observed the 8-13 μm spectrum (R ~ 250) of the Vega-like star candidate HD 145263 using Subaru/COMICS. The spectrum of HD 145263 shows the broad trapezoidal silicate feature with the shoulders at 9.3 and 11.44 μm, indicating the presence of crystalline silicate grains. This detection implies that crystalline silicate may also be commonly present around Vega-like stars. The 11.44 μm feature is slightly shifted to a longer wavelength compared to the usual 11.2-3 μm crystalline forsterite feature detected toward Herbig Ae/Be stars and T Tauri stars. Although the peak shift due to the effects of the grain size cannot be ruled out, we suggest that Fe-bearing crystalline olivine explains the observed peak wavelength fairly well. Fe-bearing silicates are commonly found in meteorites and most interplanetary dust particles, which originate from planetesimal-like asteroids. According to studies of meteorites, Fe-bearing silicate must have been formed in asteroidal planetesimals, supporting the scenario that dust grains around Vega-like stars are of planetesimal origin, if the observed 11.44 μm peak is due to Fe-bearing silicates.