Romauld Tylenda (N. Copernicus Astronomical Center, Torun, Poland)

V1309 Scorpii: a Rosetta stone in the field of red novae and contact binarie
When May 25, 2012 from 10:30 AM to 12:00 PM
  • Colloquium
Where SH, Lecture hall
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Red novae (red optical transients) form a small class of stellar eruptions, which at first sight can be (and were) considered as particular cases of classical novae, but they are not. Their principal observational characteristic is that during outburst they evolve to progressively lower effective temperatures and fade as late M-type (super)giants. V838 Mon, which erupted in 2002, is the most famous (mainly due to the spectacular light echo event, which accompanied the eruption) and best studied case in the class. We have shown, mainly on the analysis of V838 Mon, that the eruption of this type cannot result neither from classical nova thermonuclear runaway nor from late He-shell flash. Instead, we proposed that red nova eruptions result from mergers of two stars.

V1309 Sco erupted in September 2008 and was initially classified as a classical nova. Its spectroscopic evolution during and after the eruption clearly showed this was a red nova. Very fortunately it appeared that the object lies in a sky field systematically monitored in the OGLE project led by Warsaw University Observatory in Chile. As a result the OGLE archive provided us with an extraordinary set of data: more than 1300 photometric measurements of the object between 2001 and the discovery of the eruption. Our analysis showed that the progenitor of V1309 Sco was a contact binary quickly evolving to the merger of the components.