Engineering topics

Cellino, Alberto

Publications and source records attributed to Cellino, Alberto.

4 records

NASA NTRS1992

Simulated families: A test for different methods of family identification

A set of families generated in fictitious impact events (leading to a wide range of 'structure' in the orbital element space have been superimposed to various backgrounds of different densities in order to investigate the efficiency and the limitations of the methods used by Zappala et al. (1990) and by Bendjoya et al. (1990) for identifying asteroid families. In addition, an evaluation of the expected interlopers at different significance levels and the possibility of improving the definition of the level of maximum significant of a given family were analyzed.

Bendjoya, Philippe↗

NASA NTRS1992

From asteroid clusters to families: A proposal for a new nomenclature

Some confusion on the number, reliability, and characteristics of asteroid families is the result of using the single word 'family' for naming asteroid groupings identified in very different ways. Here we propose a new terminology which in our opinion would alleviate this problem.

Farinella, Paolo↗

NASA NTRS1992

A comparison between families obtained from different proper elements

Using the hierarchical method of family identification developed by Zappala et al., the results coming from the data set of proper elements computed by Williams (about 2100 numbered + about 1200 PLS 2 asteroids) and by Milani and Knezevic (5.7 version, about 4200 asteroids) are compared. Apart from some expected discrepancies due to the different data sets and/or low accuracy of proper elements computed in peculiar dynamical zones, a good agreement was found in several cases. It follows that these high reliability families represent a sample which can be considered independent on the methods used for their proper elements computation. Therefore, they should be considered as the best candidates for detailed physical studies.

Zappala, Vincenzo↗

NASA NTRS1989

Asteroid rotation rates - Distributions and statistics

An analysis of asteroid rotation rates and light-curve amplitudes disclosed many significant correlations between these rotation parameters and asteroid diameter, with distinct changes occurring near 125 km, a diameter above which self-gravity may become important. It is suggested that this size range may represent a division between surviving primordial asteroids and collisional fragments. A comparison of rotational parameters between family and nonfamily asteroids showed that the Koronis and Eos families exhibit noticeable differences, considered to be due to different impact conditions and/or to a relatively younger age for the Koronis family.

Binzel, Richard P.↗