We present new reddening measurements towards the young supernova remnant Cassiopeia A , using two techniques not previously applied to this object .
Our observations of the near-infrared [ Fe II ] 1.257 \mu m and 1.644 \mu m lines show the extinction to be highly variable across the remnant , increasing towards the west and the south , consistent with previous radio and X-ray observations .
While the absolute value of A _ { V } as determined by the [ Fe II ] lines is uncertain due to conflicting calculations and observations of their intrinsic flux ratio , parts of the remnant without previous optical measurements show comparatively higher reddening .
We find A _ { V } = 6.2 \pm 0.6 from the broadband shape of the infrared synchrotron emission of a knot within 13″ of the expansion center .
Given this reddening , the apparent faintness of the nascent supernova , and iron mass constraints from X-ray observations , we estimate an ejected mass of ^ { 56 } Ni of 0.058 - 0.16 M _ { \sun } .
Taken with \gamma -ray observations of the ^ { 44 } Ti decay chain , this nickel mass is broadly consistent with the solar ^ { 44 } Ca/ ^ { 56 } Fe ratio .