• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>The Astrophysical journal >THERMAL INFRARED IMAGING AND SPECTROSCOPY OF COMET HALE-BOPP (C/1995 O1)
【24h】

THERMAL INFRARED IMAGING AND SPECTROSCOPY OF COMET HALE-BOPP (C/1995 O1)

机译：COMET HALE-BOPP（C / 1995 O1）的热红外成像和光谱

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

We present λ = 3-5 and 8-13 μm images and long-slit spectra of comet Hale-Bopp (C/1995 O1) taken in 1997 February-April, near the time of perihelion passage. In agreement with other infrared observations, we find that the 3-13 μm spectral energy distribution was dominated by a 10 μm silicate feature with a strong underlying continuum. In the nuclear region, the feature's peak flux-to-continuum ratio varied from 2.8 on February 17 to 3.3 on April 19, and the color temperature of the 3-5 μm continuum was ～ 1.8 times the equilibrium blackbody temperature at the relevant heliocentric distance. Both quantities are larger than in any previous comet and indicate a high abundance of submicron dust particles. Spectral structure within the silicate feature reveals the presence of crystalline olivine and pyroxene grains. The physical properties of the grains, as evidenced by their infrared emission, correlated with the morphology. Within the visible jets and halos the silicate feature was up to 15% stronger, and the 8-13 μm color temperature ～1.1 times higher, than in the regions between the halos. Therefore, the halos were enriched in submicron particles relative to the background, as expected from the higher outflow velocities of these small grains. Within the halos, there was no measurable variation in the strength of the silicate feature or the color temperature with distance from the nucleus; that is, we detect no time-dependent evolution of dust particle properties (such as fragmentation) on a timescale of one rotational cycle (between ～2 and 13 hr after ejection). The spectral shape of the silicate feature was essentially the same everywhere in the inner coma in all of our 1997 spectra. Monte Carlo simulation of dust particle motions in the coma indicates that the observed patterns of jets and halos were dominated by submicron-sized grains. Modeling of the thermal emission from small grains demonstrates that the principal features of the 3-13 μm continuum and the 8-13 μm silicate feature can be synthesized from a mixture of amorphous carbon and amorphous and crystalline silicates. The overall shape of the silicate feature resembled that in other bright comets, indicating a similar mineral mix. However, the 10.0 μm peak was sharper in Hale-Bopp near perihelion than in any previously observed comet except comet Mueller (C/1993 A1) at 2 AU.
机译：我们展示了1997年2月至4月在近日点附近通过的λ= 3-5和8-13μm图像以及Hale-Bopp彗星（C / 1995 O1）的长缝光谱。与其他红外观测结果一致，我们发现3-13μm的光谱能量分布主要由10μm的硅酸盐特征所主导，具有强大的下伏连续体。在核区域中，该特征的峰值通量与连续谱的比值从2月17日的2.8变化到4月19日的3.3​​，并且3-5μm连续谱的色温是相关日心距下黑体平衡温度的〜1.8倍。 。两者的数量均大于以前的任何彗星，表明亚微米尘埃颗粒的含量很高。硅酸盐特征内的光谱结构揭示了结晶橄榄石和辉石晶粒的存在。谷物的物理性质，如其红外发射所证明，与形态有关。在可见的喷流和光晕内，硅酸盐特征比光晕之间的区域强15％，色温为8-13μm〜1.1倍。因此，相对于本底，光环富含亚微米颗粒，这是这些小颗粒较高的流出速度所期望的。在光晕内，硅酸盐特征的强度或色温没有随核距离的变化。也就是说，我们在一个旋转周期（喷射后约2至13 hr）之间没有检测到尘埃颗粒特性（例如碎片）随时间的变化。硅酸盐特征的光谱形状在我们所有的1997年光谱中，内彗彗星的各处基本相同。昏迷中尘埃粒子运动的蒙特卡洛模拟表明，观察到的喷流和光晕模式主要由亚微米级的晶粒所主导。对小晶粒的热辐射进行建模表明，可以从非晶碳，非晶硅和结晶硅酸盐的混合物中合成3-13μm连续体和8-13μm硅酸盐特征的主要特征。硅酸盐特征的整体形状类似于其他明亮彗星的特征，表明类似的矿物混合物。但是，在2 AU时，近日点附近的Hale-Bopp的10.0μm峰比除Mueller（C / 1993 A1）彗星以外的任何先前观测到的彗星都锐利。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号