Sobre a natureza dos cometas hiperbólicos

Abstract

Abstract This work presents a study of the characterization of some hyperbolic comets. These objects represent approximately $12\%$ of the total population of comets and are potentially important since within the population of hyperbolic comets are those from other planetary systems, the interstellar comets. Or still, the Manxs Comets that are objects coming from the limits of the solar system, but that have low or no activity. In order to investigate hyperbolic objects, we performed an observational study aimed at the physical characterization of these objects. We carried out systematic observations at Astronomical Observatory of Sertão de Itaparica (OASI) to obtain photometric data and at SOAR telescope to acquire spectroscopic and photometric data. In this work we analyzed the hyperbolic comet C/2017 U7 (PANSTARRS) which showed an atypical band at 0.595$\mu$m. And from there we carried out a comparative study of the colors and reflectance spectra of different populations of small bodies (for example, comets, centaurs and trans-Neptunian objects or TNOs) from the literature and concluded that the spectrum and colors of this comet are atypical, showing only some overlap with those of some known members of the TNOs and Centaurs, within the large uncertainties of the measurements of these populations. Another object studied was the hyperbolic comet C/2021 O3 (PANSTARRS) which showed a decrease in activity as it approached its perihelion and may have experienced fragmentation during this approach. This object has been classified as dynamically old.