On the relatively high concentration of the directions of long-period comet perihelion points in the North Pole region

Abstract

The origin of comets still remains an open question. Progress would be achieved if it were clear whether the comets were created in the frame of the Solar System, or if they have an interstellar origin. The hypotheses of interstellar origin are supported by, among other facts, the existence of a statistically significant preferred direction in the distribution of the direction of long-period comet perihelion points, whereby the preferred direction is located near the solar apex. However, none of the authors who have determined the preferred direction has taken into account (or taken into account adequately) the observational selection effects in the comet discoveries biasing the real distribution of comet orbits. An analysis of the selection effects is necessary if the corroct real preferred direction is to be obtained and its statistical signiflcance evaluated. Such analysis is also needed if the structure of the Oort cloud is investigated. It is well known that the sphericity of this comet reservoir is disturbed by the tidal action of the Galaxy. A correct verification of an arbitrary model of this action, for example, is impossible without the correction of a used set of comet orbits taking into account the selection effects. The paper contributes to a complete analysis of the selection effects. The existence is demonstrated of a higher number of long-period comet perihelion points per unit space angle (i.e. the concentration of these points) in the North Pole region in comparison with the other regions of the sky. At the same time, an explanation is given of the presented phenomenon as a consequence of the observational selection effects.