We present near- and mid-infrared ( IR ) photometric data of the Type Ibn supernova ( SN ) 2006jc obtained with the United Kingdom Infrared Telescope ( UKIRT ) , the Gemini North Telescope , and the Spitzer Space Telescope between days 86 and 493 post-explosion .
We find that the IR behaviour of SN 2006jc can be explained as a combination of IR echoes from two manifestations of circumstellar material .
The bulk of the near-IR emission arises from an IR echo from newly-condensed dust in a cool dense shell ( CDS ) produced by the interaction of the ejecta outward shock with a dense shell of circumstellar material ejected by the progenitor in a luminous blue variable ( LBV ) like outburst about two years prior to the SN explosion .
The CDS dust mass reaches a modest 3.0 \times 10 ^ { -4 } M _ { \odot } by day 230 .
While dust condensation within a CDS formed behind the ejecta inward shock has been proposed before for one event ( SN 1998S ) , SN 2006jc is the first one showing evidence for dust condensation in a CDS formed behind the ejecta outward shock in the circumstellar material .
At later epochs , a substantial and growing contribution to the IR fluxes arises from an IR echo from pre-existing dust in the progenitor wind .
The mass of the pre-existing CSM dust is at least \sim 8 \times 10 ^ { -3 } M _ { \odot } .
This work therefore adds to the evidence that mass-loss from the progenitors of core-collapse supernovae could be a major source of dust in the universe .
However , yet again , we see no direct evidence that the explosion of a supernova produces anything other than a very modest amount of dust .