Seminarium odbywa się w środy o 11:15 w warszawskim oddziale Centrum Astronomicznego lub w wersji online na platformie Zoom. Językiem wykładowym jest angielski; seminarium prowadzi dr Stanisław Bajtlik (adres do kontaktu seminar@camk.edu.pl). Zapraszamy również osoby spoza Centrum Astronomicznego. W sprawie szczegółów technicznych prosimy kontaktować się e-mailowo z dr. Stanisławem Bajtlikiem (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 odbywa się w poniedziałki o 11:15 w Sali Seminaryjnej warszawskiego Centrum Astronomicznego. Językiem wykładowym jest angielski. Spotkania prowadzą koordynatorzy Journal Club. Osoby zainteresowane wygłoszeniem prezentacji zachęcamy do kontaktowania się poprzez 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
