The Colloquium takes place every Wednesday at 11:15 AM - Warsaw Copernicus Astronomical Centre online by means of Zoom platform. The Colloquium is given in English and chaired by dr Stanisław Bajtlik (contact mail seminar@camk.edu.pl). People from outside of the Copernicus Center are very welcome to participate. For technical detailes please contact Dr. Stanislaw Bajtlik (bajtlik@camk.edu.pl).
Federico Gonzalez (Universidad Nacional de San Juan)
Most massive stars reside in binary or higher-order multiple systems, with important consequences for their evolution. In young stellar clusters and associations, massive multiple systems may also play a significant role in shaping the dynamical evolution of the clusters. Over the past two decades, substantial progress has been made in the observational characterization of stellar multiplicity, as well as in the detection of magnetic fields and chemical peculiarities in massive stars. In this talk I will present selected observational results that highlight the importance of multiplicity, dynamical interactions, and stellar mergers in understanding the properties of massive stars. I will also discuss ongoing work investigating the dynamical evolution of an open cluster hosting a massive quadruple system which constitutes a substantial fraction of the cluster core mass.
Journal Club takes place on Mondays at 11:15 AM in the Seminar Room. The presentation is given in English and is chaired by Journal Club Coordinators. Anyone interested in giving a Journal Club talk is encouraged to contact the email: journalclub(@camk.edu.pl).
Gabriel Tyszka (NCAC, Warsaw)
Tidal disruption events (TDEs) occur when a compact object tears apart a star with its tidal forces. In the standard interpretation of observed TDEs, the disrupting object is assumed to be a black hole. However, the cosmic censorship conjecture remains unproven, and TDEs probe the strong-field regime close to the central object, making them a potentially useful test of alternatives such as naked singularities. In this talk, we investigate whether a naked singularity described by the Reissner-Nordström metric with Q > M can be distinguished from a black hole through observations of TDEs. We perform smoothed particle hydrodynamics (SPH) simulations of the disruption of a Sun-like star using the PHANTOM code, and compare the dynamics of the debris in both cases. We then use ray tracing to compute bolometric light curves and search for differences that could serve as observational signatures of a naked singularity. We discuss the preliminary results and their implications for testing cosmic censorship with TDEs.
Presenting his work
