IRAS Observations of Novae. IV. Modeling Source Confusion

In a series of papers we have extracted and presented Infrared Astronomy Satellite (IRAS) data on novae and related objects. The high detection rate of these objects, approximately 40%, was difficult to explain. We suggested that source confusion at the faint levels achieved by coadded IRAS data could be the origin of many of these detections. In this paper we examine the problem of source confusion more closely using a model of the point source mid-infrared sky by Wainscoat et al. (1992). This model predicts that source confusion in the IRAS 12 and 25 micron coadded data is unlikely to occur outside the regions closest to the galactic center. We conclude that novae and related objects are sources of mid-infrared radiation. Continuing our survey of novae and related objects, we present IRAS coadded data on greater than 90 objects not covered in our previous papers.