  SN 2010jl is a Type IIn core collapse supernova whose radiative output is
powered by the interaction of the SN shock wave with its surrounding dense
circumstellar medium (CSM). After day ~60, its light curve developed a NIR
excess emission from dust. This excess could be a thermal IR echo from
pre-existing CSM dust, or emission from newly-formed dust either in the cooling
postshock region of the CSM, or in the cooling SN ejecta. Recent analysis has
shown that dust formation in the CSM can commence only after day ~380, and has
also ruled out newly-formed ejecta dust as the source of the NIR emission. The
early (< 380 d) NIR emission can therefore only be attributed to an IR echo.
The H-K color temperature of the echo is about 1250 K. The best fitting model
requires the presence of about 1.6e-4 Msun of amorphous carbon dust at a
distance of 2.2e16 cm from the explosion. The CSM-powered luminosity is
preceded by an intense burst of hard radiation generated by the breakout of the
SN shock through the stellar surface. The peak burst luminosity seen by the CSM
dust is significantly reduced by Thomson scattering in the CSM, but still has
the potential of evaporating the dust needed to produce the echo. We show that
the survival of the echo-producing dust provides important constraints on the
intensity, effective temperature, and duration of the burst.
