Evidence for Differentiation among Asteroid Families

Planetesimals ◽  
2017 ◽  
pp. 298-320 ◽  
Author(s):  
Thomas H. Burbine ◽  
Francesca E. Demeo ◽  
Andrew S. Rivkin ◽  
Vishnu Reddy
Keyword(s):  
Asteroid Families

Asteroid families: evidence of ageing of the proper elements

Icarus ◽  
2004 ◽  
Vol 169 (2) ◽  
pp. 341-356 ◽  
Author(s):  
A. Dell'Oro ◽  
G. Bigongiari ◽  
P. Paolicchi ◽  
A. Cellino
Keyword(s):  
Proper Elements ◽  
Asteroid Families

scholarly journals An anisotropic distribution of spin vectors in asteroid families

2013 ◽  
Vol 559 ◽  
pp. A134 ◽  
Author(s):  
J. Hanuš ◽  
M. Brož ◽  
J. Ďurech ◽  
B. D. Warner ◽  
J. Brinsfield ◽  
...  
Keyword(s):  
Asteroid Families

scholarly journals Machine learning classification of new asteroid families members

2020 ◽  
Author(s):  
Valerio Carruba
Keyword(s):  
Machine Learning ◽  
Family Members ◽  
Classification Algorithms ◽  
New Members ◽  
Machine Learning Classification ◽  
New Family ◽  
Robotic Telescope ◽  
Traditional Approaches ◽  
Asteroid Families

<p>Asteroid families are groups of asteroids that are the product of collisions or of the rotational fission of a parent object.  These groups are mainly identified in proper elements or frequencies domains.   Because of robotic telescope surveys, the number of known asteroids has increased from about 10,000 in the early 90's to more than 750,000 nowadays. Traditional approaches for identifying new members of asteroid families, like the hierarchical clustering method (HCM), may   struggle to keep up with the growing rate of new discoveries. Here we used machine learning classification algorithms to identify new family members based on the orbital distribution in proper (a,e,sin(i)) of previously known family constituents. We compared the outcome of nine classification algorithms from stand alone and ensemble approaches.  The Extremely Randomized Trees (ExtraTree) method had the highest precision, enabling to  retrieve up to 97% of family members identified with standard HCM.</p>

scholarly journals Asteroid Proper Elements: The Big Picture

1994 ◽  
Vol 160 ◽  
pp. 143-158 ◽  
Author(s):  
Zoran Knežević ◽  
Andrea Milani
Keyword(s):  
Point Of View ◽  
Dynamical Structure ◽  
Main Belt ◽  
Secular Resonances ◽  
Mean Motion Resonances ◽  
Mean Motion ◽  
Proper Elements ◽  
Big Picture ◽  
Linear And Nonlinear ◽  
Asteroid Families

Four perturbation theories presently used to compute asteroid proper elements are reviewed, and their results are briefly discussed (Milani and Knežević, 1990, 1992, 1994, for low to moderate eccentricity/inclination main belt objects; Lemaitre and Morbidelli, 1994, for high e, I objects; Milani, 1993, for Trojans; Schubart, 1982, 1991 for Hildas). The most important recent improvements are described, in particular those pertaining to the upgrades of the previous analytic and semianalytic solutions. The dynamical structure of the asteroid main belt, as defined by the low order mean motion resonances and by linear and nonlinear secular resonances, is considered from the point of view of the effects of these resonances on the accuracy and/or reliability of the computation of proper elements and on the reliability of the identification of asteroid families.

Asteroid Families

1994 ◽  
pp. 395-414 ◽  
Author(s):  
Vincenzo Zappalà ◽  
Alberto Cellino
Keyword(s):  
Asteroid Families

The common origin of family and non-family asteroids: Implications for meteorites and NEAs

2018 ◽  
Vol 14 (S345) ◽  
pp. 281-282
Author(s):  
Stanley F. Dermott ◽  
Dan Li ◽  
Apostolos A. Christou
Keyword(s):  
Hierarchical Clustering ◽  
Common Origin ◽  
Clustering Method ◽  
Main Belt ◽  
Frequency Distributions ◽  
Size Frequency ◽  
The Family ◽  
The Common ◽  
The Mean ◽  
Asteroid Families

AbstractThe observed size-frequency distributions (SFDs) of the five major asteroid families in the Inner Main Belt (IMB), defined by Nesvorný (2015) using the Hierarchical Clustering Method (Zappala et al. 1990), are distinctly different and deviate significantly from the linear log-log relation described by Dohnanyi (1969). The existence of these differences in the SFDs, and the fact that the precursor bodies of the major families have distinctly different eccentricities and inclinations, provides an explanation for the observations that the mean sizes of both the family and the non-family asteroids are correlated with their mean proper eccentricities and anti-correlated with their mean proper inclinations. We deduce from this, and from the fact that the SFDs of the family and the non-family asteroids are almost identical, that the family and most of the non-family asteroids in the IMB have a common origin (Dermott et al. 2018).

scholarly journals The Galileo Encounters with Gaspra and IDA

1994 ◽  
Vol 160 ◽  
pp. 357-365
Author(s):  
Clark R. Chapman
Keyword(s):  
Solar System ◽  
Spectral Data ◽  
Magnetic Anomalies ◽  
Spatial Variations ◽  
Two Bodies ◽  
Asteroid Families

The Galileo spacecraft encounters with 951 Gaspra and 243 Ida have provided the first close-up pictures and measurements of asteroids. These two small, S-type asteroids are both irregular in shape, confirming generalized pre-encounter interpretations from groundbased data. Gaspra is lightly cratered by small, fresh craters whereas Ida's surface is heavily covered by craters of all sizes and in all stages of degradation. Unless there are major differences in strength between these two bodies, Ida may be about 10 times older than Gaspra – approaching the age of the solar system. Both asteroids have grooves, although not as prominent as on Phobos. Ida has a population of boulders, particularly near its ends. While Ida seems to have a deep regolith, Gaspra is more nearly in a state of erosion, although there is evidence for an older megaregolith. The data are thus far not conclusive about the geophysical properties of these objects (e.g. whether they are rubble piles) and there are as yet no firm conclusions about how asteroid families are produced by catastrophic collisions. Interesting spectral data relevant to the S-type asteroid controversy (e.g. spatial variations on Gaspra) may lead to some useful generalizations after the remaining Ida data are returned and analyzed in spring 1994. Unexpected magnetic anomalies observed in the vicinities of both asteroids are being studied.

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