Mid-Infrared Interferometric Monitoring of Evolved Stars: The Dust Shell Around the Mira Variable RR Aquilae at 13 Epochs
Abstract
Aims: We present a unique multi-epoch infrared interferometric study of the oxygen-rich Mira variable RR Aql in comparison to radiative transfer models of the dust shell. We investigate flux and visibility spectra at 8-13 microns with the aim of better understanding the pulsation mechanism and its connection to the dust condensation sequence and mass-loss process. Methods: We obtained 13 epochs of mid-infrared interferometry with the MIDI instrument at the VLTI between April 2004 and July 2007, covering minimum to pre-maximum pulsation phases (0.45-0.85) within four cycles. The data are modeled with a radiative transfer model of the dust shell where the central stellar intensity profile is described by a series of dust-free dynamic model atmospheres based on self-excited pulsation models. We examined two dust species, silicate and Al2O3 grains. We performed model simulations using variations in model phase and dust shell parameters to investigate the expected variability of our mid-infrared photometric and interferometric data.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 2011
- Accession Number
- ADA567508
Entities
People
- D. A. Boboltz
- E. Fossat
- I. Karovicova
- K. Ohnaka
- M. Scholz
- M. Wittkowski
Organizations
- United States Naval Observatory