High angular resolution observations in the near infrared and modeling of the peculiar envelope of HD 62623

Abstract

We report new observations of the peculiar star HD 62623 obtained with aperture masking interferometry performed on the Keck I telescope at lambda = 1.24, 1.65, 2.26 and 3.08 μm. The envelope around this star appears partially resolved in the near infrared except at 1.65 μm. Radiative transfer modeling of the dust shell of this star has been performed in spherical geometry. This modeling has two goals: it provides a framework for understanding the partially resolved object shown by the visibility curves, and it allows investigation of the envelope of HD 62623 by discrimination between proposed models. We show that reasonable fits to photometric observations can be obtained with a simple spherically symmetric silicate dust shell. Nevertheless, our high angular resolution measurements bring some important constraints on the modeling of the circumstellar environment of HD 62623. More realistic model involving the presence of a non spherically distributed dust envelope including the gas component in the circumstellar environment is required.