Approach of the NGC1977 Star Cluster to the TOI-2796 Host Star

Abstract

We searched for a rapprochement in space between a star cluster and an extrasolar planetary system in past epochs. We have found that a host star TOI-2796 is a candidate for such an encounter with the cluster NGC 1977. We estimated time and distance between the objects of such a rapprochement. These parameters allowed us to estimate the gravitational effect on the loss of comets from a hypothetical analogue of the Oort cloud of the TOI-2796. The place of the encounter in the sky is shown. This point can be considered to be the place of appearance of interstellar comets. We confirm and suggest that there is possibility of past and future stellar close encounters of stars with star clusters which can perturb the analogue of the Oort cloud’s stability and triggering cometary showers in the vicinity of giant planets. The orbital parameters for the sample are calculated using the galpy package. The MWPotential14 gravitational potential is used, composed of a power law, exponentially cut-off bulge, Miyamoto–Nagai potential disc, and Navarro–Frenk–White dark matter halo. Time calculations were carried out within the age limits of the objects considered. The color-absolute magnitude diagram and the isochron system were used to calculate the age of the cluster. By extending the tracks of the cluster and stars’ motion in past epochs (~5.4 Myr), the time of the maximum approach (≈30 pc) of the TOI-2796 star, hosting a planetary system, with NGC 1977 has been found. As a result of our research, we derived that the host star’s approach with the cluster might entail effects related with the cluster’s gravitational pull on the nuclei of comets located in the outer border of the planetary system’s Oort cloud. The impact of approach on Oort cloud comets has been estimated.