Dust scattering in the Miras R Car and RR Sco resolved by optical interferometric polarimetry

M. J. Ireland*, P. G. Tuthill, J. Davis, W. Tango

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

53 Citations (Scopus)

Abstract

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.

Original languageEnglish
Pages (from-to)337-344
Number of pages8
JournalMonthly Notices of the Royal Astronomical Society
Volume361
Issue number1
DOIs
Publication statusPublished - 21 Jul 2005
Externally publishedYes

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