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		| Paper: | 
		Dust Signatures from Late-time Infrared and Optical Observations of SN 1998S | 
	 
	
		| Volume: | 
		342, 1604-2004: Supernovae as Cosmological Lighthouses | 
	 
	
		| Page: | 
		337 | 
	 
	
		| Authors: | 
		Pozzo, M.; Meikle, W.P.S.; Fassia, A.; Geballe, T.; Lundqvist, P.; Chugai, N.N.; Sollerman, J. | 
	 
	
	
		| Abstract: | 
		We present late-time IR (1-5 μm) and optical observations of the type IIn SN 1998S up to about 1200 days post-explosion. The shape and evolution of the Hα and He I 1.083 μm line profiles indicate a powerful interaction with a massive progenitor wind and provide evidence of dust condensation within the ejecta. 1.5-2.5 μm spectra and HKL'M' photometry reveal strong IR emission due to hot dust in the ejecta and/or circumstellar medium (CSM). For the origin of the IR emission we favour dust condensation (at least 10−3 MSolar) in a cool dense shell (CDS) as the main IR source but do not rule out a contribution from the CSM. The late-time evolution of the intrinsic (K-L') colour of type II supernovae (SNe) may be a potentially useful tool for determining the presence or absence of a massive CSM around their progenitors. | 
	 
	
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