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

Comet C/2013 A1 Siding Spring. How treatment of data and NG effects can change our predictions about close encounters with Mars ?

We show that the estimates of close encounter of this comet with Mars depend on data treatment. Using the data taken in the two-year period, we derived that the comet will miss Mars on 2014 October 19 at the distance of about $140\,150\pm 55$ km or $140\,300\pm 45$ km from its center, depending on the method of data processing in the purely gravitational model of motion (based on non-weighted data or weighted data, respectively). Unfortunately, the non-gravitational model of motion is still very uncertain, thus we can only speculate about estimates of expected distances for non-gravitational orbital solutions. However, we did not obtain a significant differences in close encounter prediction between the non-gravitational solutions and the gravitational ones.Comment: 5 pages, 2 figure

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

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&

Nierówności w stanie zdrowia między kobietami a mężczyznami w kontekście płci biologicznej oraz społeczno-kulturowej

Uznając płeć jako jeden z istotnych wyznaczników nierówności w stanie zdrowia pomiędzy kobietami a mężczyznami, należy zwrócić uwagę na dwa typy zależności. Pierwszy odpowiadać będzie zróżnicowaniu wynikającemu z przyczyn biologicznych (sex), drugi natomiast – ze społeczno-kulturowych (gender). Obok przyczyn biologicznych wynikających z płci biologicznej, nierówności w stanie zdrowia pomiędzy kobietami a mężczyznami biorą się również z odmiennych wzorów zachowań w ramach pełnionych ról społecznych, odmiennych stylów życia czy zróżnicowanych postaw wobec zdrowia i choroby, które z kolei warunkowane są wieloma różnorodnymi czynnikami społeczno-kulturowymi, wśród których ważną rolę odgrywają stereotypy płci. Odmienne sposoby socjalizowania dziewczynek i chłopców do ról małżeńsko-rodzinnych oraz zawodowych, odmienny rodzaj więzi społecznych charakteryzujący kobiety i mężczyzn, odmienne cechy osobowości uznawane za typowo „kobiece” lub „męskie” – mają bezpośredni wpływ na pozycje obu płci w stratyfikacji społecznej. Wykształcenie, dostęp do pracy, wykonywany zawód czy dochody różnicują dodatkowo w znacznym stopniu postawy wobec zdrowia i choroby. Płeć kulturowa (gender) kształtowana jest już w toku wczesnej socjalizacji i podtrzymywana przez strukturę społeczną, stąd wzory kulturowe w odniesieniu do kobiecości i męskości uwidaczniające się w wielu sferach życia społecznego dotyczą również praktykowania zachowań zdrowotnych zagrażających zdrowiu czy antyzdrowotnych. Mężczyźni i kobiety charakteryzują się odmiennym podejściem do dbania o zdrowie, do profilaktyki zdrowotnej, do zachowań zagrażających zdrowiu czy antyzdrowotnych. Stereotypy związane z płcią w istotny sposób wpływają za zdrowie somatyczne oraz psychiczne kobiet i mężczyzn

Warsaw Catalogue of cometary orbits: 119 near-parabolic comets

Context. The dynamical evolution of near-parabolic comets strongly depends on the starting values of the orbital elements derived from the positional observations. In addition, when drawing conclusions about the origin of these objects, it is crucial to control the uncertainties of orbital elements at each stage of the dynamical evolution. Aims. I apply a completely homogeneous approach to determine the cometary orbits and their uncertainties. The resulting catalogue is suitable for the investigation of the origin and future of near-parabolic comets. Methods. First, osculating orbits were determined on the basis of positional data. Second, the dynamical calculations were performed backwards and forwards up to 250 au from the Sun to derive original and future barycentric orbits for each comet. In the present investigation of dynamical evolution, the numerical calculations for a given object start from the swarm of virtual comets constructed using the previously determined osculating (nominal) orbit. In this way, the uncertainties of orbital elements were derived at the end of numerical calculations. Results. Homogeneous sets of orbital elements for osculating, original and future orbits are given. The catalogue of 119 cometary orbits constitutes about 70 per cent of all the first class so-called Oort spike comets discovered during the period of 1801-2010 and about 90 per cent of those discovered in 1951-2010, for which observations were completed at the end of 2013. Non-gravitational (NG) orbits are derived for 45 comets, including asymmetric NG~solution for six of them. Additionally, the new method for cometary orbit-quality assessment is applied for all these objects.Comment: 32 pages including tables given in appendices, 3 figues, accepted for publication in A &