Browsing by Author "Micheli, M."

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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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    The Aegis orbit determination and impact monitoring system and services of the ESA NEOCC web portal
    (Springer, 2024-12-01) Fenucci, M.; Faggioli, L.; Gianotto, F.; Bracali Cioci, D.; Cano, J. L.; Conversi, L.; Devogèle, M.; Di Girolamo, G.; Drury, C.; Föhring, D.; Gisolfi, L.; Kresken, R.; Micheli, M.; Moissl, R.; Ocaña, F.; Oliviero, D.; Porru, A.; Ramirez-Moreta, P.; Rudawska, R.; Bernardi, F.; Bertolucci, A.; Dimare, L.; Guerra, F.; Baldisserotto, V.; Ceccaroni, Marta; Cennamo, R.; Chessa, A.; Del Vigna, A.; Koschny, D.; Teodorescu, A. M.; Perozzi, E.
    The NEO Coordination Centre (NEOCC) of the European Space Agency is an operational centre that, among other activities, computes the orbits of near-Earth objects and their probabilities of impact with the Earth. The NEOCC started providing information about near-Earth objects in 2012 on a dedicated web portal, accessible at https://neo.ssa.esa.int/. Since the beginning of the operational phase, many developments and improvements have been implemented regarding the software, the data provided, and the portal. One of the most important upgrades is that the NEOCC is now independently providing data through a newly developed Orbit Determination and Impact Monitoring system, named Aegis. All the data computed by Aegis are publicly available on the NEOCC web portal, and Aegis is also used to maintain all the major services offered. The most important services comprise an orbital catalogue of all known asteroids, a list of possible future impacts with the Earth (also called Risk List), a list of forthcoming close approaches, a set of graphical toolkits, and an on-demand ephemerides service. Many of the services are also available through dedicated APIs, which can be used to automatically retrieve data. Here we give an overview of the algorithms implemented in the Aegis software and provide a summary of the services offered by the NEOCC that are supported by Aegis.