The Catalogue of Cometary Orbits and their Dynamical Evolution

The new cometary catalogue containing data for almost 300 long-period comets that were discovered before 2018 is announced (the CODE catalogue). This is the first catalogue containing cometary orbits in five stages of their dynamical evolution, covering three successive passages through the perihelion, except the hyperbolic comets which are treated in a different manner. For about 100 of these long-period comets, their non-gravitational orbits are given, and for a comparison also their orbits obtained while neglecting the existence of non-gravitational acceleration are included. For many of the presented comets different orbital solutions, based on the alternative force models or various subsets of positional data are additionally given. The preferred orbit is always clearly indicated for each comet.Comment: 6 pages, 3 figures, public database: https://pad2.astro.amu.edu.pl/comets submitted for publication in A&

On the dynamical history of the interstellar object 'Oumuamua?

1I/2017 U1 'Oumuamua is the first interstellar object recorded inside the Solar System. We try to answer the main question: where does it come from? To this aim we searched for close encounters between 'Oumuamua and all nearby stars with known kinematic data during their past motion.We had checked over 200 thousand stars and found just a handful of candidates. If we limit our investigation to within a 60 pc sphere surrounding the Sun, then the most probable candidate for the 'Oumuamua parent stellar habitat is the star UCAC4 535-065571. However GJ 876 is also a favourable candidate. Moreover, the origin of 'Oumuamua from a much more distant source is still an open question. Additionally, we found that the quality of the original orbit of 'Oumuamua is accurate enough for such a study and that none of the checked stars had perturbed its motion significantly. All numerical results of this research are available in the Appendix.Comment: 11 pages, 4 main tables and 3 tables with data, 8 figures, accepted for publication in A&A (v.4: rewritten and figures added

Where do long-period comets come from? 26 comets from the non-gravitational Oort spike

The apparent source region (or regions) of long-period comets as well as the definition of the dynamically new comet are still open questions.The aim of this investigation is to look for the apparent source of selected long period comets and to refine the definition of dynamically new comets. We show that incorporation of the non-gravitational forces into the orbit determination process significantly changes the situation. We determined precise non-gravitational orbits of all investigated comets and next followed numerically their past and future motion during one orbital period. Applying ingenious Sitarski's method of creating swarms of virtual comets compatible with observations, we were able to derive the uncertainties of original and future orbital elements, as well as the uncertainties of the previous and next perihelion distances. We concluded that the past and future evolution of cometary orbits under the Galactic tide perturbations is the only way to find which comets are really dynamically new. We also have shown that a significant percentage of long-period comets can visit the zone of visibility during at least two or three consecutive perihelion passages.Comment: Accepted for publication in MNRA

Note on the dynamical evolution of C/2017 K2 PANSTARRS

(Abreviated) Comet C/2017 K2 PANSTARRS drew attention to its activity already at a time of its discovery in May 2017 when it was about 16 au from the Sun. This Oort spike comet will approach its perihelion in December 2022, and the question about its dynamical past is one of the important issues to explore. To this aim it is necessary to obtain its precise osculating orbit, its original orbit, and propagate its motion backwards in time to the previous perihelion. We study a dynamical evolution of C/2017 K2 to the previous perihelion (backward calculations for about 3-4 Myr) as well as to the future (forward calculations for about 0.033 Myr). Outside the planetary system both Galactic and stellar perturbations were taken into account. We derived that C/2017 K2 is a dynamically old Oort spike comet (1/a$_{prev}$ = (48.7 $\pm$ 7,9) x10$^{-6}$ au$^{-1}$) with the previous perihelion distance below 10 au for 97 per cent of VCs (nominal q$_{prev}$ = 3.77 au). It means that C/2017 K2 has already visited our planetary zone during its previous perihelion passage. Thus, it is almost certainly a dynamically old Oort spike comet.Comment: Previous version was published as "Dynamical evolution of C/2017 K2 PANSTARRS", Kr\'olikowska & Dybczy\'nsli, 2018, A&A, 615, A170 This version is supplemented by an Addendum (pages 5-6) which contains updated results based on new observations of this come

Neškodljivost kalupnih pjesaka sa bentonitom i svijetlećim nositeljima ugljika

Procedures have been developed to determine the volume, rate and composition (particularly BTEX: benzene, toluene, ethylbenzene and xylenes and PAHs (polycyclic aromatic hydrocarbons)) of gas evolution from moulds and cores prepared with various binders as a means of harmfulness of moulding sands. The rate of gas evolution from green sands with four different lustrous carbon carrier and BTEX content were determined. The gas evolution rates are highest in the range of about 20 to 30 s after contact with molten metal. In practice during the first 200-250 s the total emission of gases generated in investigated samples occurred. The main emitted component from the BTEX group was benzene.Postupci su razvijeni za određivanje volumena, brzine i sastava (posebice BTEX: benzen, toluen, etilbenzen, xilana) i PAH (policiklički automatski hidrokarbonati) plina koji nastaje iz kalupa i jezgri na različitim nosačima u težnji za neškodljivost kalupnih pijesaka. Brzine nastajanja plina iz pripravljenih pijesaka sa 4 različita svijetleća nositelja ugljika i sadržajem BTEX su određeni. Brzine nastajanja plina su najveće u razini 20 do 30 s poslije dodira sa rastopljenim metalom. Praktično, tijekom prvih 200-250 s ostvaruje se ukupna emisija stvorenih plinova u istraživanim uzorcima. Iz BTEX skupine, benzen je glavna emitirajuća komponenta