Broadband infrared photometry of comet Hale-Bopp with ISOPHOT ?
Broadband infrared photometry of comet Hale-Bopp with ISOPHOT ?
复制标题
使用 ISOPHOT 对海尔波普彗星进行宽带红外光度测量？
DOI：
10.1051/0004-6361:20011139
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发表时间：
2001
影响因子：
6.5
通讯作者：
J. Zarnecki
中科院分区：
文献类型：
--
作者：
E. Grün;M. Hanner;S. Peschke;T. Müller;H. Boehnhardt;T. Brooke;H. Campins;J. Crovisier;C. Delahodde;I. Heinrichsen;H. Keller;R. Knacke;H. Krüger;P. Lamy;C. Leinert;D. Lemke;C. Lisse;Michael Müller;D. Osip;M. Šolc;M. Stickel;M. Sykes;V. Vanýsek;J. Zarnecki
海尔-波普彗星被欧空局红外空间天文台（ISO）的ISOPHOT光度计在4.6至2.8 Au之间观测了5次。每一次，宽带测光进行使用4 dierent探测器，5个光圈和10 lters覆盖3.6和170 m之间的范围。背景观测是在彗星观测几天后，在天空的相同位置用相同的仪器设置进行的。的观测策略和数据减少的步骤进行了一些详细的描述，包括技术，以纠正可变探测器的响应。给出了Hale-Bopp观测值的带内功率值及其不确定性。平均不确定度为25%。计算最终通量时考虑了黄道背景、彗星位置距光圈中心的可能位置、彗发内的亮度分布以及彗星辐射的光谱能量分布。在所有的数据集中，即使在r =4：6{4：9 Au前近日点和3.9 Au后近日点，也检测到来自广泛尺寸分布的尘埃颗粒的强热发射;总热能变化为r 3。7.3{12.8 m}的色温是黑体温度的1.5倍，比在任何其他彗星上观测到的都要高。硅酸盐功能在10和25米是突出的，在所有5个数据集，最大的日心距离，硅酸盐排放已被发现在彗星。在4.6{4.9 Au}处60 m的过量发射表明存在结晶水冰粒，如果冰粒比平衡黑体稍热，则与观察到的QOH一致。尘埃的平均散射度高于P/Halley彗星，但低于Hale-Bopp近近日点的其他散射度测量值。没有证据表明在4.6 Au处有一种冷而明亮的冰粒成分增强了散射光。硅酸盐和吸收颗粒的混合物的简单模型与2.8 Au的ISO光谱和光度学进行了比较。在>100 mr处观察到的通量等于其中大部分质量集中在大颗粒中的尺寸分布。在2.8 Au和4.6 Au处，尘埃产生率分别为1：5 × 10 5和3 × 10 4 kg s-1，对应的尘埃气体质量比为6 ~ 10。
Comet Hale-Bopp was observed ve times with ISOPHOT, the photometer on board ESA's Infrared Space Observatory (ISO) between 4.6 and 2.8 AU. Each time, broadband photometry was performed using 4 dierent detectors, 5 apertures and 10 lters covering the range between 3.6 and 170 m. Background ob- servations were performed with identical instrument settings at the same positions on the sky several days after the comet observations. The observation strategy and the data reduction steps are described in some detail, including the techniques to correct for variable detector responsivity. The resulting inband power values of the Hale-Bopp observations and their uncertainties are given. The mean uncertainty is 25%. The nal fluxes were computed, taking into account the zodiacal background, possible oset of the comet's position from the center of the aperture, the brightness distribution within the coma, and the spectral energy distribution of the comet's emission. Strong thermal emission from a broad size distribution of dust particles was detected in all of the data sets, even at r =4 :6{4:9 AU pre-perihelion and 3.9 AU post-perihelion; the total thermal energy varied as r 3 . The 7.3{12.8 m color temperature was1.5 times the blackbody temperature, higher than that observed in any other comet. Silicate features at 10 and 25 m were prominent in all 5 data sets, the largest heliocentric distances that silicate emission has been detected in a comet. The presence of crystalline water ice grains is suggested from the 60 m excess emission at 4.6{4.9 AU, consistent with the observed QOH if the icy grains were slightly warmer than an equilibrium blackbody. The average albedo of the dust is higher than that of comet P/Halley, but lower than other albedo measurements for Hale-Bopp nearer perihelion. There is no evidence for a component of cold, bright icy grains enhancing the scattered light at 4.6 AU. Simple models for a mixture of silicate and absorbing grains were t to the ISO spectra and photometry at 2.8 AU. The observed flux at >100 mr equires a size distribution in which most of the mass is concentrated in large particles. Dust production rates of order 1:5 10 5 kg s 1 at 2.8 AU and 3 10 4 kg s 1 at 4.6 AU have been found. They correspond to dust to gas mass ratios of 6 to 10.