PUBLICATIONS OF THE ASTRONOMICAL OBSERVATORY OF BELGRADE104, Page 153-158, https://doi.org/10.69646/aob104p153
PROCEEDINGS of the XX Serbian Astronomical Conference, Belgrade, October 16 - 20, 2023, Edited by Jelena Petrović, Dušan Marčeta and Ana Lalović
Published by: Astronomical Observatory, Volgina 7, 11060 Belgrade 38, Serbia

Abstract. In the GAIA Data Release 3 catalogue, published in 2023, there are 15021 stars classified as Cepheids. We will use a sub-sample of stars classified as Type II Cepheids (T2C) from the GAIA catalogue that have all the necessary parameters (full astrometry and radial velocity) to calculate the galactocentric orbits of these stars. For this we will use the analytical potential proposed earlier by one of the authors. We will calculate angular momentum and energy of the stars to determine if they belong to some of the known mergers, as it has been shown that satellite galaxies of the Milky Way can be considered as particles with very similar integrals of motion. We will analyse the distribution of the energy and angular momentum for our sample of stars. It is very likely that most of the T2Cs were created in the Milky Way however, there is a subgroup of T2Cs that have significantly different metallicities than the other stars. This could be an indication that they might have originated from different surroundings, such as a different galaxy, and came to the Milky Way via a merger event. In this work we will examine this possibility.