The evolution of the dust shell of Nova Serpentis 1978

Photometric measurements of Nova Serpentis 1978 from V to 19.5 microns covering the first 240 days of the nova's development are reported. A free-free expansion phase was followed by the condensation of a dust shell that became optically thick at both visible and infrared wavelengths. Carbon grains grew to radii of approximately 0.3 microns during the condensation period. The grains appeared to sputter or evaporate for a period of approximately 100 days following infrared maximum. It is found that the condensed carbon comprised 2% of the ejected mass, which implies that carbon abundance was enhanced in the nova shell. The angular expansion rate of the shell yields a distance of approximately 5 kpc and a luminosity of approximately 3000 solar luminosities for Nova Serpentis 1978.