Razvoj algoritma za ispitivanje pripadnosti asteroida familijama
Development of an algorithm for examination of the association of asteroids to families
Докторанд
Radović, ViktorМентор
Novaković, BojanЧланови комисије
Novaković, BojanKnežević, Zoran
Marčeta, Dušan
Метаподаци
Приказ свих података о дисертацијиСажетак
Glavni cilj ove disertacije je unapredenje pristupa identikaciji clanova familija
asteroida metodom hijerarhijskog grupisanja. U proceduru se dodaje novi korak
koji omogucava smanjenje tzv. lancanog efekta. Uvedeni algoritam se sastoji od
cetiri glavna koraka. U prvom se primenom metode hijerarhijskog grupisanja na
inicijalnom katalogu sopstvenih elemenata odreduje preliminarna lista clanova. U
drugom koraku, koristeci poznate zicke karakteristike potencijalnih clanova, a na
osnovu denisanih kriterijuma, identikuju se uljezi. U trecem koraku, identikovani
uljezi se izbacuju iz inicijalnog kataloga sopstvenih orbitalnih elemenata cime
se dobija novi, modikovani katalog. Konacno, u cetvrtom koraku ponovo se primenjuje
metoda hijerarhijskog grupisanja, ali ovaj put na modikovanom katalogu
sopstvenih elemenata. Pokazano je da se na ovaj nacin znacajno smanjuje broj
potencijalnih uljeza u familijama asteroida. Osim toga data je kriticka analiza dobijenih
rezultata, kao i detaljan prikaz nek...ih specicnih slucajeva. Takode, razvijen
je i onlajn portal (Asteroids Families Portal; AFP) koji omogucava dostupnost ove
metode siroj naucnoj zajednici.
Drugi cilj disertacije je odredivanje granice za primenu metode integracije unazad,
kojom se procenjuje starost mladih familija asteroida. Taj cilj je postignut
upotrebom numerickih simulacija evolucije test familije. Odredivanjem trenutka
grupisanja sekularnih uglova
i $, ustanovljena je linearna zavisnost izmedu dubine
minimuma grupisanja i starosti familije. Prema dobijenim rezultatima, metoda
integracije unazad moze se uspesno primeniti na familije koje nisu starije od 18 miliona
godina.
The main goal of this dissertation is improvement of an approach for identi-
cation of the members of asteroid families, based on the hierarchical clustering
method. An additional step is introduced in order to reduce a so-called chaining
eect. The introduced algorithm consists of four main steps. In the rst step, the
hierarchical clustering method is applied to the initial catalogue of proper elements
in order to obtain a preliminary list of family members. In the second step, using
available physical properties, and based upon the dened criteria, the interlopers are
identied. In the third step, objects identied as interlopers in the second step, are
excluded from the initial catalogue of proper orbital elements, producing a modied
catalogue. Finally, in the fourth step, the HCM analysis is performed again, but this
time using the modied catalogue of proper elements. It is shown that in this way
a number of potential interlopers among family members is signicantly reduced.
Moreover, a...n on-line based portal (Asteroids Families Portal; AFP) to apply this
procedure is developed, and is freely available to all interested researchers.
The second goal of the dissertation is to determine the limitations of the backward
integration method, used for estimation of ages of young asteroid families. This
aim is achieved through numerical simulations of the evolution of a ctitious family.
By determining instants of secular angles
i $ clustering, a linear relationship is
found between the depth of a clustering and the age of a family. According to the
obtained results, the backward integration method could be successfully applied to
families not older than 18 Myrs.