2000/03/10 by Peter Tuthill, P. G. Tuthill, W. C. Danchi +5 · 42 citations
Earth and Planetary Sciences · Physics and Astronomy · #Astronomy #Astrophysics #Astrophysics and Star Formation Studies #Atmospheric Ozone and Climate #Brightness #Infrared #Interferometry #Photosphere #Physics #Spectral line #Stars #Stellar, planetary, and galactic studies #Very Large Telescope #astro-ph
paper · pdf · doi:10.1086/308782
published in The Astrophysical Journal 534(2), 907-914 (IOP Publishing) · Accepted to Astrophysical Journal. To appear in volume 534. 14 pages; 3 postscript figures
arxiv created 2000/03/10 · openalex publication_date 2000/05/10 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/06
The results of a high-resolution interferometric campaign targeting the symbiotic long-period variable (LPV) R Aqr are reported. With both near-infrared measurements on baselines out to 10 m and mid-infrared data extending to 32 m, we have been able to measure the characteristic sizes of regions from the photosphere of the LPV and its extended molecular atmosphere out to the cooler circumstellar dust shell. The near-infrared data were taken using aperture-masking interferometry on the Keck I telescope and show R Aqr to be partially resolved for wavelengths out to 2.2 μm but with a marked enlargement, possibly due to molecular opacity, at 3.1 μm. Mid-infrared interferometric measurements were obtained with the Univeristy of California, Berkeley, infrared spatial interferometer (ISI) operating at 11.15 μm from 1992 to 1999. Although this data set is somewhat heterogeneous with incomplete coverage of the Fourier plane and sampling of the pulsation cycle, clear changes in the mid-infrared brightness distribution were observed, both as a function of position angle on the sky and as a function of pulsation phase. Spherically symmetric radiative transfer calculations of uniform-outflow dust shell models produce brightness distributions and spectra which partially explain the data; however, limitations to this approximation are noted. Evidence for significant deviation from circular symmetry was found in the mid-infrared and more tentatively at 3.08 μm in the near-infrared; however, no clear detection of binarity or of non-LPV elements in the symbiotic system is reported.