Observational Evidence for Hot Subdwarfs Formed by Triple Evolution

Triple star evolution, although it is quite common among stars in general, has not been studied observationally to that end for sdO/Bs yet. The small number of confirmed triples among those objects might lead to the conclusion, that the impact of triple evolution is negligible. However, we found evidence for a much higher fraction of wide tertiaries around sdB+MS binaries and theoretical models predict numerous faint, undetectable tertiaries such as low-mass main sequence stars or white dwarfs, which hints at significant selection biases. We might therefore severely underestimate the true number of triples containing sdO/Bs. Furthermore, because of their dynamical evolution initial triple systems may end up as binaries or single stars, because of merger and ejection events. In this talk I will provide an overview of the known sdO/Bs in triple systems and other candidates for triple evolution.