2005/05/06 by M. J. Ireland, Michael Ireland, P. G. Tuthill +5 · 57 citations
Earth and Planetary Sciences · Physics and Astronomy · #Astronomy #Astrophysics #Astrophysics and Star Formation Studies #Atmospheric Ozone and Climate #Brightness #Circumstellar dust #Cosmic dust #Dust lane #Galaxy #Interferometry #Opacity #Optics #Physics #Polarimetry #RADIUS #Scattering #Silicate #Star formation #Stars #Stellar, planetary, and galactic studies #Surface brightness #astro-ph
paper · pdf · doi:10.1111/j.1365-2966.2005.09181.x
published in Monthly Notices of the Royal Astronomical Society 361(1), 337-344 (Oxford University Press) · 8 pages, 4 figures, accepted for MNRAS
arxiv created 2005/05/06 · openalex publication_date 2005/07/01 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We present optical interferometric polarimetry measurements of the Mira-like variables R Car and RR Sco, using the Sydney University Stellar Interferometer. By making visibility measurements in two perpendicular polarizations, the relatively low-surface brightness light scattered by atmospheric dust could be spatially separated from the bright Mira photospheric flux. This is the first reported successful use of long-baseline optical interferometric polarimetry. Observations were able to place constraints on the distribution of circumstellar material in R Car and RR Sco. The inner radius of dust formation for both stars was found to be less than 3 stellar radii: much closer than the expected innermost stable location for commonly assumed astrophysical ‘dirty silicate’ dust in these systems (silicate dust with a significant iron content). A model with the dust distributed over a shell which is geometrically thin compared to the stellar radius was preferred over an outflow. We propose dust components whose chemistry and opacity properties enable survival at these extreme inner radii.