Testing the inversion of asteroids’ Gaia photometry combined with ground-based observations
Testing the inversion of asteroids’ Gaia photometry combined with ground-based observations
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DOI：
10.1093/mnras/stv631
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发表时间：
2015-04
影响因子：
4.8
通讯作者：
T. Santana-Ros;P. Bartczak;T. Michałowski;P. Tanga;A. Cellino
中科院分区：
文献类型：
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作者：
T. Santana-Ros;P. Bartczak;T. Michałowski;P. Tanga;A. Cellino
我们研究了遗传算法的可靠性，该算法将用于反演由欧洲太空探测任务收集的小行星的光度测量。为此，我们对1万颗具有不同自转轴方向、旋转周期和形状的小行星进行了几组模拟。每个模拟所用的观测历元都是从天文台开发的任务模拟器中提取的，使用az -缓冲标准图形方法生成。我们还探讨了不同σ值高斯噪声污染数据集对反演结果的影响。这项研究使我们能够确定反演方法的可靠性与小行星的极纬度之间的相关性。特别是，对于具有准球形和低极纬度的小行星，结果是有偏差的。这种影响是由于在这种情况下观察到的低光曲线幅度造成的，因为当两个值相当时，周期信号可能会在光度随机噪声中丢失，从而导致反演失败。在分析反演结果时，可以考虑到这种偏差，而不是用非引力等物理效应来误导它。最后，我们研究了全光曲线和盖亚光度同时采集对反演结果的影响。使用这个程序，我们已经证明，对于少于50个数据点的小行星，有可能减少错误解决方案的数量。后者对于规划基于地面的小行星观测具有特别重要的意义，旨在增强盖亚对太阳系科学的科学影响。
We investigated the reliability of the genetic algorithm which will be used to invert the photometricmeasurementsofasteroidscollectedbytheEuropeanSpaceAgencyGaiamission. To do that, we performed several sets of simulations for 10 000 asteroids having different spin axis orientations, rotational periods and shapes. The observational epochs used for each simulation were extracted from theGaiamission simulator developed at the Observatoire de la ChebrightnesswasgeneratedusingaZ-bufferstandardgraphicmethod.We also explored the influence on the inversion results of contaminating the data set with Gaussian noise with different σ values. The research enabled us to determine a correlation between the reliability of the inversion method and the asteroid's pole latitude. In particular, the results are biased for asteroids having quasi-spherical shapes and low pole latitudes. This effect is caused by the low light-curve amplitude observed under such circumstances, as the periodic signal can be lost in the photometric random noise when both values are comparable, causing the inversion to fail. Such bias might be taken into account when analysing the inversion results, not to mislead it with physical effects such as non-gravitational forces. Finally, we studied what impact on the inversion results has combining a full light curve and Gaia photometry collected simultaneously. Using this procedure we have shown that it is possible to reduce the number of wrong solutions for asteroids having less than 50 data points. The latter will be of special importance for planning ground-based observations of asteroids aiming to enhance the scientific impact of Gaia on Solar system science.