Unraveling the Dusty Environment of RT Vir: A Radiative Transfer Modeling Approach to Exploring an Odd AGB Star

The Oxygen-Rich Asymptotic Giant-Branch (AGB) star RT Virginis, like many of its counterparts, is surrounded by gas and dust as it loses its atmosphere to space. However, RT Vir presents an interesting target for study due to the odd shape of its observed infrared spectrum. Most O-rich AGB stars have strong silicate emission features in their spectra at 10 microns, accompanied by other emission features that correspond to chemical components and morphology of the dust grains and gases that surround the star. However, Spitzer, IRAS LRS and ISO SWS spectra of RT Vir indicate a mostly featureless dust spectrum, with a weak feature at ~20um. Here we use the 1D radiative transfer code DUSTY to fit model spectra to SWS and LRS data. Using these tools, we hope to expose the underlying causes of RT Vir’s odd spectral profile, in terms of its dust shell parameters, e.g.., dust grain temperature, composition, dust shell density profile and dust shell size.