arXiv subjects

Tadeusz J. Jopek

Publications and source records attributed to Tadeusz J. Jopek.

5 recordsLinked to original sources

arXiv2022

Status of the IAU Meteor Data Center

Since 2007, the Meteor Data Center (MDC) has had two components: the Orbital database (OD) and the Shower database (SD). The orbital part is in charge of the efficient collection, checking, and dissemination of geocentric parameters and orbits of individual orbits. Is also acts as a central depository for meteoroid orbits obtained by different techniques: photographic, television, video, CCD and radar. The shower database collects the geocentric and orbital parameters of the meteor showers and meteoroids streams. It is not an archive of all information related to meteor showers, its primary task is to give unique names and codes to new meteor showers (streams). The SD acts in conjunction with the Working Group on Meteor Shower Nomenclature of International Astronomical Union (IAU) Commission F1, "Meteors, Meteorites, and Interplanetary Dust". In our paper, we give a concise description of the IAU MDC database, its origin, structure and, in particular, the current requirements for the introduction of new orbital and shower data.

astro-ph.IM↗

arXiv2020

The orbital clusters among the near Earth asteroids

Fifteen orbital clusters (associations) were identified among ~20000 near Earth asteroids (NEAs). All associations were found with a high statistical reliability using a single linkage cluster analysis algorithm and three orbital similarity functions. The identified groups constitute a small fraction (4.74 %) of the entire sample. Nonetheless they may be hazardous to the Earth and its inhabitants. As it happens with meteoroid streams, every year the Earth comes very close to the orbits of each association. In two cases (2008TC3 and 2017FU102) the distance between the asteroid's and the Earth's orbits was smaller than our planet's radius. Among the members of the identified associations we found 331 objects larger than the Chelyabinsk asteroid and all of them approach the Earth's orbit at a distance smaller than 0.05 [au]. Two of the identified groups (4179) Toutatis and (251430) Itokawa support catastrophic origins of Toutatis and Itokawa asteroids. This study does not focus on the origin of the NEA associations, but on tracing them. Regardless of their origin, the identified groups pose a serious threat to the Earth. Hence, to facilitate their monitoring of we calculated coordinates of the theoretical radiants and calendar dates of their potential activity.

astro-ph.EP↗

arXiv2016

Probability of coincidental similarity among the orbits of small bodies - I. Pairing

Probability of coincidental clustering among the orbits of comets, asteroids and meteoroids depends on many factors like: the size of the orbital sample searched for clusters or the size of the identified group, it is different for groups of 2,3,4, ... members. Probability of coincidental clustering is assessed by the numerical simulation, therefore, it depends also on the method used for the synthetic orbits generation. We tested the impact of some of these factors. For a given size of the orbital sample we have assessed probability of random pairing among several orbital populations of different sizes. We have found how these probabilities vary with the size of the orbital samples. Finally, keeping fixed size of the orbital sample we have shown that the probability of random pairing can be significantly different for the orbital samples obtained by different observation techniques. Also for the user convenience we have obtained several formulae which, for given size of the orbital sample, one can use to calculate the similarity threshold corresponding to the small value of the probability of coincidental similarity among two orbits.

astro-ph.EP↗

arXiv2014

Stream and sporadic meteoroids associated with Near Earth Objects

NEOs come close to the Earth's orbit so that any dust ejected from them, might be seen as a meteor shower. Orbits evolve rapidly, so that a similarity of orbits at one given time is not suffcient to prove a relationship, orbital evolution over a long time interval also has to be similar. Sporadic meteoroids can not be associated with a single parent body, they can only be classified as cometary or asteroidal. However, by considering one parameter criteria, many sporadics are not classified properly therefore two parameter approach was proposed.

astro-ph.EP↗

arXiv2014

The Near Earth Asteroid associations

We have made an extensive search for grouping amongst the near Earth asteroids (NEAs). We used two D- functions and rigorous cluster analysis approach. We have found sev- eral new groups (associations) among the NEAs: the objects moving on similar orbits with small minimum orbital intersection distances (MOID) with the Earth trajectory. Reliability of some of these groups is quite high.

astro-ph.EP↗