Bogumił Pilecki (CAMK, Warsaw)
Since 2020, we have been systematically identifying and characterizing double-lined (SB2) binary Cepheids in the Large Magellanic Cloud, the Small Magellanic Cloud, and the Milky Way. Our primary detection method exploits the apparent overbrightness of Cepheids as a signature of a luminous companion, complemented by searches for systems composed of two Cepheid components. This effort has increased the known sample of confirmed SB2 Cepheids to 62 objects —an order-of-magnitude improvement over previous numbers— and expanded the number of double-Cepheid binaries from one to ten. For 37 systems, we detected anticorrelated orbital motion of both components, providing definitive proof of binarity. Preliminary orbital solutions have been derived for 24 systems with periods up to seven years, and full spectroscopic orbits have been determined for 15 systems with periods up to 3 years. I will present the orbital and physical properties of these binaries and discuss their implications for Cepheid multiplicity, evolution, and origin. Remarkably, at least 10% of them exhibit evidence of past mergers, suggesting that a significant fraction of Cepheids may form through binary interaction. I will also address the possible consequences of these findings for calibrating the Cepheid distance scale.
Leda Berni (INAF- Osservatorio Astrofisico di Arcetri (Florence, Italy))
Martin Solar (Adam Mickiewicz University, Poznań)
Core-collapse supernovae are very energetic explosions that have a significant impact in the interstellar medium within galaxies. However, it is not well understood how progenitors of core-collapse supernovae form, evolve, and explode. In this talk, I plan to constrain the core-collapse supernova progenitor properties studying their star formation efficiency (or molecular gas depletion time) environments. In summary, it is found that interacting massive binaries occur in regions of intense, efficient star formation rather than simply higher gas content.
Dominika Król (Harvard Smithonian CfA)
Maciek Wielgus (Instituto de Astrofísica de Andalucía, IAA-CSIC, Granada, Hiszpania)
Laetitia Gibaud (Department of Physics, University of Białystok)
Samik Mitra (Astrophysics and Relativity Group International Centre for Theoretical Sciences, Bengaluru, India)
