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Session: Stars, Planets and the Interstellar Medium

Name: Prof. Eleftheria-Pan. Christopoulou (University of Patras)
Coauthors: No coauthors were included.
Type: Oral
Title: Discovery of star systems at the merger limit by large astronomical sky surveys.
Abstract:

The mass ratio of a contact binary system evolves towards smaller values due to mass transfer, magnetic braking, and thermal oscillations until it reaches a minimum value threshold. Then the system undergoes tidal instability (Darwin instability) and is driven to a merger of its components, during which it suddenly flashes as a red nova. I will present methods for detecting new candidate systems from large modern surveys, which in combination with photometric observations, both space and ground-based at different wavelengths, and sophisticated analysis lead to the extraction of their physical parameters in order to study them statistically. Why only one such system has been observed to date? Can we consider also ultrashort period contact systems (with periods below the period cut-off ) as progenitors of red novae?