Discovery of Crystalline Silicates in Comet C/2001 Q4 (NEAT)
Discovery of Crystalline Silicates in Comet C/2001 Q4 (NEAT)
复制标题
在彗星 C/2001 Q4 (NEAT) 中发现结晶硅酸盐
DOI：
10.1086/424593
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发表时间：
2004
期刊：
影响因子：
--
通讯作者：
D. Harker
中科院分区：
文献类型：
--
作者：
D. Wooden;C. Woodward;D. Harker
我们展示了使用 NASA Ames HIFOGS 分光光度计观测到的近日点前 5 天（rh = 0.97 AU，Δ = 0.35 AU，2004 年 5 月 11.25 和 11.30 UT）动态的新奥尔特云彗星 C/2001 Q4 (NEAT) 的 10 μm 硅酸盐特征。 Q4彗星的硅酸盐特征包含在10.0和11.2μm处的强结晶峰，以及在9.3、10.5和11.8μm处的较弱的峰，这是结晶橄榄石和结晶斜方辉石的特征。 Q4 彗星中共振峰的相对高度以及硅酸盐特征的形状与彗星 C/1995 O1 (Hale-Bopp) 近日点相同 (rh = 1.21 AU)。热发射模型显示 Q4 和 Hale-Bopp 具有相似的硅酸盐矿物相对丰度和较高的硅酸盐结晶与非晶态比率。然而，Q4 彗星得出的硅酸盐与无定形碳比率低于海尔-波普彗星，并且在 2 小时内变化约 2 倍，可能会从彗发中的不同喷流中采样材料。由于Q4和海尔-波普之间的硅酸盐矿物学相似，这两种冰微星子要么在同一区域形成，要么结晶硅酸盐广泛分布在彗星形成区内。
We present the 10 μm silicate feature of the dynamically new Oort Cloud comet C/2001 Q4 (NEAT) 5 days prior to perihelion (rh = 0.97 AU, Δ = 0.35 AU, 2004 May 11.25 and 11.30 UT) observed with the NASA Ames HIFOGS spectrophotometer. The silicate feature of comet Q4 contains strong crystalline peaks at 10.0 and 11.2 μm, along with weaker peaks at 9.3, 10.5, and 11.8 μm, which are characteristic of crystalline olivine and crystalline orthopyroxene. The relative heights of the resonant peaks as well as the shape of the silicate feature in comet Q4 is the same as in comet C/1995 O1 (Hale-Bopp) preperihelion (rh = 1.21 AU). Thermal emission modeling shows Q4 and Hale-Bopp have similar relative abundances of the silicate minerals and high silicate crystalline-to-amorphous ratios. The silicate-to-amorphous carbon ratio derived for comet Q4, however, is lower than in Hale-Bopp and varies by a factor of ~2 in 2 hr, potentially sampling material from different jets in the coma. Owing to the similarity in the silicate mineralogy between Q4 and Hale-Bopp, either these two icy planetesimals formed in the same regime or crystalline silicates were widely distributed within the comet-forming zone.
影响因子：
3.2
作者：
V. Mannings;A. Boss;S. Russell
通讯作者：
V. Mannings;A. Boss;S. Russell