1993 · 11 citations · 0 references
Natural SciencesAstronomyPhysicsAstrophysicsInfrared AstronomyStellar AstronomyCloud Optical PropertiesInterstellar DustInterstellar Dust EmissionStellar AtmospheresStellar EvolutionYoung Stellar ObjectsCircumstellar Dust EmissionCircumstellar Dust ShellsCloud Optical VariabilityDust Grain PropertiesInfrared Dust EmissionInfrared Excess EmissionOptical PropertiesPhotometric Data Analysis
WW Vulpeculae is an evolutionarily young and irregular variable star coinciding with the infrared point source IRAS 19238 + 2106. The most conspicuous features of the lightcurve are the aperiodically occurring Algol-like minima with amplitudes up to 1.5 mag. Relevant UBVR data show that these minima originate from individual dust clouds moving in a circumstellar dust shell. The photometric data indicate different optical properties of the grain populations in these dust clouds. The reddening parameter R = A V /E(B − V) has been found to vary in the range from 3.5 to 7 for the individual clouds observed. The observed infrared excess supports the circumstellar origin of the optical variability