Stellar mergers: the triple origin of blue stragglers, and a new type of stellar explosion
Abstract: I will discuss two different issues, the origin of blue stragglers and a new type of stellar explosion. Blue stragglers are stars that seem much younger then the stellar population in which they are observed. Two main mechanisms have bee suggested for their origin; either rejuvenation through through stellar collisions or through close binary mergers. I will suggest a third novel formation mechanism of blue stragglers from triple systems, which can explain many of their surprising properties, not explained by the currently studied mechanisms. In the second part of the talk I will discuss the discovery of a unique supernova, SN 2005E, which is a new type of stellar explosion, arising from
helium detonation on white dwarfs, and its implications.