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arXiv 1108.3095astro-ph.EP
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主带彗星的大小和轨道分布的极限

Limits on the Size and Orbit Distribution of Main Belt Comets

S. Sonnett, J. Kleyna, R. Jedicke, J. Masiero

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58 pages, 9 figures
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摘要：

七颗已知的主带彗星（MBC）具有主带小行星的轨道特征，但也表现出彗星般的尘埃喷射。为了限制它们的物理和轨道特性，我们使用两种诊断方法搜索了千颗小行星光曲线调查（TALCS; Masiero et al. 2009）以寻找其他候选者：尾部和彗发检测。这是迄今为止最敏感的MBC调查工作，将搜索范围从H~18（D~1公里）扩展到H~21（D~150米）。我们适合的924个TALCS对象的PSF模型，将彗发和核组件来测量的总表面亮度的彗发的分数贡献。我们使用相同的算法在可比较的零检测样本上确定了慧差检测的重要性。我们没有发现任何MBC候选人与这种技术的灵敏度限制的顺序彗星质量损失率约0.1公斤/秒。我们的尾部检测算法确定了统计上显着的通量在候选对象周围的分割环。我们表明，该技术可以检测到整个小行星带的尾巴活动的水平，目前已知的MBC。虽然我们没有确定任何MBC候选人与这种技术，我们发现一个统计上显着的检测微弱的活动在整个合奏的TALCS小行星。这表明许多主带小行星的活动水平非常低。我们设置了90%的置信上限的数量分布的MBC作为一个函数的绝对星等，半长轴，偏心率和倾角。在主带中有<~ 400000个MBC亮于H_V=21（~150 m），MBC：MBA比值<~ 1：400。我们进一步评论的能力，有意义地约束雪线的位置的意见。在一些合理和简单的假设下，我们声称85%的置信度，当代雪线位于2.5 AU以外。

英文摘要：

The seven known main belt comets (MBCs) have orbital characteristics of main belt asteroids yet exhibit dust ejection like comets. In order to constrain their physical and orbital properties we searched the Thousand Asteroid Light Curve Survey (TALCS; Masiero et al. 2009) for additional candidates using two diagnostics: tail and coma detection. This was the most sensitive MBC survey effort to date, extending the search from MBCs with H~18 (D~1 km) to H~21 (D~150 m). We fit each of the 924 TALCS objects to a PSF model incorporating both a coma and nuclear component to measure the fractional contribution of the coma to the total surface brightness. We determined the significance of the coma detection using the same algorithm on a sample of comparable null detections. We did not identify any MBC candidates with this technique to a sensitivity limit on the order of cometary mass loss rate of about 0.1 kg/s. Our tail detection algorithm identified statistically significant flux in a segmented annulus around the candidate object. We show that the technique can detect tail activity throughout the asteroid belt to the level of the currently known MBCs. Although we did not identify any MBC candidates with this technique, we find a statistically significant detection of faint activity in the entire ensemble of TALCS asteroids. This suggests that many main belt asteroids are active at very low levels. We set 90% upper confidence limits on the number distribution of MBCs as a function of absolute magnitude, semimajor axis, eccentricity, and inclination. There are <~ 400000 MBCs in the main belt brighter than H_V=21 (~150 m) and the MBC:MBA ratio is <~ 1:400. We further comment on the ability of observations to meaningfully constrain the snow line's location. Under some reasonable and simple assumptions we claim 85% confidence that the contemporary snow line lies beyond 2.5 AU.

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