We have looked at SN 1987A with ISO SWS/LWS. The supernova was not detected in any of the spectra. In particular, we have derived upper limits for the fluxes of [Fe I] 24.05 and [Fe II] 25.99 , and made time dependent calculations for the late line emission from the supernova. We have assessed various uncertainties to the models, and for a plausible line profile we then find an upper limit on the mass of ejected 44Ti, . Together with the preliminary results of KF99 this brackets the ejected mass of 44Ti to the range , which is close to the yield of 44Ti in models of the explosion by Woosley & Weaver (1995), Thielemann et al. (1996) and Nagataki et al. (1997). The lower limit is probably less stringent than the upper, as indicated by the results of Borkowski et al. (1997). A more direct limit on can be made when instruments measuring the gamma-ray line emission from the 44Ti decay will be available.
The only emission our ISO observations detect is from gas and dust in the direction toward the supernova. In particular, the [O III] 51.8 and [O III] 88.4 lines indicate a gas density of cm-3, and the dust continuum can be explained by a temperature of K. A second dust component with K may also be present.
© European Southern Observatory (ESO) 1999
Online publication: June 30, 1999