  We performed a Cr-K emission line survey in young supernova remnants (SNRs)
with the Chandra archival data. Our sample includes W49B, Cas A, Tycho and
Kepler. We confirmed the existence of the Cr line in W49B and discovered this
emission line in the other three SNRs. The line center energies, equivalent
widths (EWs) and fluxes of the Cr lines are given. The Cr in Cas A is in a high
ionization state while that in Tycho and Kepler is in a much lower one. We find
a good positive correlation between Cr and Fe line center energies, suggesting
a common origin of Cr and Fe in the nucleosynthesis, which is consistent with
the theoretical predictions. We propose that the EW ratio between Cr and Fe can
be used as a supplementary constraint on the progenitors' properties and the
explosion mechanism.

Astrophysics