Modeling the Circumstellar Dust around TX Pisces

In order to ascertain the nature of the dust around TX Pisces (TX Psc), a carbon-rich asymptotic giant branch (AGB) star, we used a radiative transfer (RT) code, DUSTY, to model its spectra. These types of stars have dust shells that are a result of mass loss containing carbon atoms which collide and condense to form solids. Some compounds that are likely to be found include graphitic carbon, silicon carbide, and amorphous carbon as well as metallic iron. Because of these chemical interactions, these stars eject dust and gas and are major contributors of new elements and dust into the interstellar medium. TX Psc was observed spectroscopically by both the Infrared Space Observatory Short Wavelength Spectrometer (ISO-SWS), and the Infrared Astronomical Satellite (IRAS). We generated synthetic spectral energy distributions (SEDs) using DUSTY by making adjustments to the inner dust shell temperatures, shell density, and chemical abundances. To further constrain the input parameters for the dust shell models, we used the carbon-to-oxygen (C/O) ratio, mass-loss rate, and light curve. Using these quantities, along with the light curve, we were able to estimate the star’s temperature and the pressure-temperature (P-T) space around the star. The results of DUSTY are presented.