Browsing by Author "Faggioli, Laura"

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    Influence of the dynamic classification of asteroids on observation astrometric errors: a statistical analysis
    (Oxford University Press, 2023-03-24) Stronati, Nicolo'; Faggioli, Laura; Micheli, M.; Ceccaroni, Marta
    The ephemerides of minor planets are computed on the basis of astrometric observations. The asteroid orbit determination process requires these observations to be properly weighted to take into account the expected accuracy of the data. If not directly provided by the observers, the weights are, in general, computed after a station-specific statistical analysis on the observation residuals, where the influence of external factors such as epoch of observation, magnitude, and employed catalogue has been proven. In this paper, we perform a statistical analysis on observation residuals of the major surveys taking into account a new factor, i.e. the dynamical classification of asteroids, to understand whether the observation quality may have a dependence on the different type of observed object. If an influence is actually found, then it will be possible to develop a new weighting system based on these results. The weights will be easily applicable once one knows the asteroid orbit. In particular, four stations have been found having different qualities depending on whether they are observing near-Earth asteroids or main-belt asteroids. Moreover, the cross-correlation between the dynamic classification and epoch, magnitude, and catalogue is investigated, as well as the influence of these factors on observations’ quality.
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    Statistical analysis of a weighting scheme for asteroid observation astrometric errors taking into consideration the classification of the observed asteroids
    (International Astronautical Federation (IAF), 2022-09-22) Stronati, Nicolo; Faggioli, Laura; Micheli, Marco; Ceccaroni, Marta
    Observations of asteroids and other near-Earth objects are of great importance for planetary defence activities, the purpose of which is to determine their positions in space and the probabilities of Earth impacts, as well as developing strategies to mitigate this risk. In this framework, having precise observations is important to describe accurately the orbits of near-Earth asteroids. However, given a general absence of a-priori uncertainty information, the single observations are given proper weights that reflect the accuracy expected by the observers who perform the observations. The weights are calculated for each observer on the base of statistical analysis of systematic and random errors and providing them with an accurate definition is necessary if the magnitude of the error of a single observation is to be correctly estimated. In this paper a statistical analysis on the residuals of the astrometric data provided by the major surveys is presented introducing a dynamic classification of observed asteroids. The observations are thus subdivided between those relative to Near Earth and Main Belt Asteroids and the quality of the data for each station is studied focussing on this classification. The results show that most of the considered stations have the same quality regardless of the measured object, while four of them show a dependency on this factor.