Abstract
We have measured the optical and infrared light curve of SN2000cx, a Type Ia supernova located in the outer part of an S0 galaxy, using observations taken at CTIO telescopes. We expected for it to have little reddening, but the Bmax - Vmax method implies a larger value of color excess E(B-V ) = 0.176+-0.104. Other standard methods based on matching this light curve with a "typical" type Ia SN (AJ 118, 1766, 1999; ApJ 539, 658, 2000) show an unphysical negative reddening. Finally, the light curve of this SN looks normal but we found that this object has intrinsic colors much different than we expected. This tells us that the relations between colors and decline rate are not as universal as we initially thought.
