Gaia Data Release 2 Observations of solar system objects
Gaia Data Release 2 Observations of solar system objects
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盖亚数据发布 2 太阳系天体观测
DOI：
10.1051/0004-6361/201832900
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发表时间：
2018
影响因子：
6.5
通讯作者：
Brown
中科院分区：
文献类型：
--
作者：
Spoto F;Tanga P;Mignard F;Berthier J;Carry B;Cellino A;Dell'Oro A;Hestroffer D;Muinonen K;Pauwels T;Petit J M;David P;De Angeli F;Delbo M;Frezouls B;Galluccio L;Granvik M;Guiraud J;Hern;ez J;Ordenovic C;Portell J;Poujoulet E;Thuillot W;Walmsley G;Brown
欧洲空间局（ESA）的宇宙飞船自开始运行以来一直在确保对太阳系物体（SSOs）的观测。数据发布2 （DR2）包含对14,099个sso选定样本的观测结果。这些小行星已经被小行星中心识别并编号。在CCD水平上提供了每个gaia观测的位置。作为补充天文测量的额外信息，我们还为选定的观测提供了未滤波边缘带的sso的视亮度。我们将解释SSO数据的处理，并描述我们用于选择inGaiaDR2发布的样本的标准。然后我们探索数据集以评估其质量。方法利用aiadr2系统的主要数据产品——小行星历元天体测量，需要考虑其位置信息几乎是一维的不确定度的异常性质。如果这方面处理得当，则可以获得与用于定义天体测量不确定度的单个值的先验误差模型总体一致的轨道拟合后残差。描述了随机误差和系统误差的作用。残差的分布使我们能够识别数据集中可能存在的污染物（如恒星）。gband的光度测量与参考小行星形状的计算值以及红色和蓝色光度计（RP和BP）在相应时期记录的通量进行了比较。结果总体天文测量性能接近预期，最佳亮度范围为g ~ 12−17。在这个范围内，典型的凌日级精度远低于1mas。对于较暗的小行星，光子噪声的增长会使性能恶化。较亮的小行星（ang ~ 12）受到其信号处理性能较低的影响。通过与存档数据的比较和对细微非引力效应的探测的初步测试，证明了gaiadr2天体测量给SSOs带来的巨大改进。
ContextTheGaiaspacecraft of the European Space Agency (ESA) has been securing observations of solar system objects (SSOs) since the beginning of its operations. Data Release 2 (DR2) contains the observations of a selected sample of 14,099 SSOs. These asteroids have been already identified and have been numbered by the Minor Planet Center repository. Positions are provided for eachGaiaobservation at CCD level. As additional information, complementary to astrometry, the apparent brightness of SSOs in the unfilteredGband is also provided for selected observations.AimsWe explain the processing of SSO data, and describe the criteria we used to select the sample published inGaiaDR2. We then explore the data set to assess its quality.MethodsTo exploit the main data product for the solar system inGaiaDR2, which is the epoch astrometry of asteroids, it is necessary to take into account the unusual properties of the uncertainty, as the position information is nearly one-dimensional. When this aspect is handled appropriately, an orbit fit can be obtained with post-fit residuals that are overall consistent with the a-priori error model that was used to define individual values of the astrometric uncertainty. The role of both random and systematic errors is described. The distribution of residuals allowed us to identify possible contaminants in the data set (such as stars). Photometry in theGband was compared to computed values from reference asteroid shapes and to the flux registered at the corresponding epochs by the red and blue photometers (RP and BP).ResultsThe overall astrometric performance is close to the expectations, with an optimal range of brightnessG~ 12 − 17. In this range, the typical transit-level accuracy is well below 1 mas. For fainter asteroids, the growing photon noise deteriorates the performance. Asteroids brighter thanG~ 12 are affected by a lower performance of the processing of their signals. The dramatic improvement brought byGaiaDR2 astrometry of SSOs is demonstrated by comparisons to the archive data and by preliminary tests on the detection of subtle non-gravitational effects.