Poster abstract details

We report the new X-ray ephemerides of the dipping source 4U 1323-619. We collected 26 years of data to build the ephemerides that were obtained estimating the dip arrival times. The most accurate estimation of the orbital period of 4U 1323-619 is of 2.941923(5) hrs, but we actually have few information on the companion star and on the mass transfer mechanism. Using all the available archival data of 4U 1323-619 we obtained 12 dip arrival times covering 26 years of observations. The corresponding delays were fitted using both a linear and a quadratic functional form. We obtain an estimation of the orbital period compatible with the estimations present in literature but with an accuracy ten times higher. Furthermore, the quadratic ephemeris allows us to obtain for the first time an upper limit to the orbital period derivative of the system. Assuming that the companion star is in thermal equilibrium in the lower main sequence, for a neutron star of 1.4 M$_{\odot}$, we infer a mass of 0.24 M$_{\odot}$ for the companion star. Using a 3D extinction map of the K$_{s}$ radiation of the Galaxy, we obtain a distance to the source of 4.2$^{+0.8}_{-0.7}$ kpc. This distance implies a luminosity which is consistent with the adopted scenario in which the companion star is in thermal equilibrium.