A new analytical thin-dusty-shell model to interpret interferometric data
Application to the S star π1 Gruis
Observatoire de la Côte d'Azur, Laboratoire Gemini, UMR-CNRS 6203, av. Copernic, 06130 Grasse, France e-mail: firstname.lastname@example.org
Accepted: 6 February 2006
High angular resolution techniques allow the determination of physical and geometrical parameters characterizing the circumstellar dusty environment of late-type stars. The resolution of the radiative transfer equation under the thin-shell approximation provides an analytical expression for the interferometric visibility profile, which can then be compared to simple ad-hoc geometrical models and to physical models based on radiative transfer. Using the DUSTY numerical code to calculate theoretical visibilities of the S star π1 Gru, in agreement with spectrophotometric measurements from the near to the far infrared, we compared the validity of the output parameters found by the least-square analysis of the visibility, given with the thin-shell model and with a simple disk+ring geometrical model of the envelope. The results are discussed in terms of fitting the shape of the intensity profile and of the number of free parameters to be considered.
Key words: radiative transfer / methods: analytical / techniques: interferometric / circumstellar matter / stars: late-type / infrared: stars
© ESO, 2006