  We measure the metallicity of the unusual hypervelocity star HE 0437-5439
from high resolution spectroscopy to be half-solar. We determine a spectral
type of B2 IV-III for the star and derive an effective temperature Teff= 21,500
+/- 1,000 K and a surface gravity log(g) = 3.7 +/- 0.2 (cgs). We also present
BV time series photometry and find the star to be non-variable at the 0.02 mag
level. We refine the magnitude of the hypervelocity star to V=16.36+/-0.04 mag,
with a color B-V=-0.23+/-0.03 mag, confirming its early-type nature. Our
metallicity result establishes the origin of HE 0437-5439 in the Large
Magellanic Cloud and implies the existence of a massive black hole somewhere in
this galaxy.
