Lagos, FelipeSchreiber, Matthias R.Hernández, M-HTappert, ClausZorotovic, MónicaCáceres, C.2021-11-222021-11-222020F Lagos, M R Schreiber, S G Parsons, A Zurlo, D Mesa, B T Gänsicke, R Brahm, C Caceres, H Canovas, M-S Hernandez, A Jordan, D Koester, L Schmidtobreick, C Tappert, M Zorotovic, The White Dwarf Binary Pathways Survey −III. Contamination from hierarchical triples containing a white dwarf, Monthly Notices of the Royal Astronomical Society, Volume 494, Issue 1, May 2020, Pages 915–922, https://doi.org/10.1093/mnras/staa747http://repositoriobibliotecas.uv.cl/handle/uvscl/2711The White Dwarf Binary Pathways Survey aims at increasing the number of known detached A, F, G, and K main-sequence stars in close orbits with white dwarf companions (WD+AFGK binaries) to refine our understanding about compact binary evolution and the nature of Supernova Ia progenitors. These close WD+AFGK binary stars are expected to form through common envelope evolution, in which tidal forces tend to circularize the orbit. However, some of the identified WD+AFGK binary candidates show eccentric orbits, indicating that these systems are either formed through a different mechanism or perhaps they are not close WD+AFGK binaries. We observed one of these eccentric WD+AFGK binaries with SPHERE and find that the system TYC 7218-934-1 is in fact a triple system where the WD is a distant companion. The inner binary likely consists of the G-type star plus an unseen low-mass companion in an eccentric orbit. Based on this finding, we estimate the fraction of triple systems that could contaminate the WD+AFGK sample. We find that less than 15 per cent of our targets with orbital periods shorter than 100 d might be hierarchical triples.enMETHODS: NUMERICALMETHODS: STATISTICALBINARIES: CLOSESTARS: KINEMATICS AND DYNAMICSArticulo