When Do Stars Go BOOM?
  The maximum mass of a star that can produce a white dwarf (WD) is an
important astrophysical quantity. One of the best approaches to establishing
this limit is to search for WDs in young star clusters in which only massive
stars have had time to evolve and where the mass of the progenitor can be
established from the cooling time of the WD together with the age of the
cluster. Searches in young Milky Way clusters have not thus far yielded WD
members more massive than about 1.1$~M_{\odot}$, well below the Chandrasekhar
mass of $1.38~M_{\odot}$, nor progenitors with masses in excess of about
$6~M_{\odot}$. However, the hunt for potentially massive WDs that escaped their
cluster environs is yielding interesting candidates. To expand the cluster
sample further, we used HST to survey four young and massive star clusters in
the Magellanic Clouds for bright WDs that could have evolved from stars as
massive as 10$~M_{\odot}$. We located five potential WD candidates in the
oldest of the four clusters examined, the first extragalactic single WDs thus
far discovered. As these hot WDs are very faint at optical wavelengths, final
confirmation will likely have to await spectroscopy with 30-metre class
telescopes.
