Related papers: Diffraction-limited speckle interferometry and mod…
We report interferometric observations of the semi-regular variable star RS CrB, a red giant with strong silicate emission features. The data were among the first long baseline mid-infrared stellar fringes obtained between the Keck…
We present the results of UBVJHKLM photometry of R CrB spanning the period from 1976 to 2001. Studies of the optical light curve have shown no evidence of any stable harmonics in the variations of the stellar emission. In the L band we…
WR 118 is a highly evolved Wolf-Rayet star of the WC10 subtype surrounded by a permanent dust shell absorbing and re-emitting in the infrared a considerable fraction of the stellar luminosity. We present the first diffraction-limited…
We present near-infrared speckle interferometry of the OH/IR star OH 104.9+2.4 in the K' band obtained with the 6m telescope of the Special Astrophysical Observatory (SAO). At a wavelength of lambda = 2.12 micron the diffraction-limited…
We present new near-infrared (JHK) bispectrum speckle-interferometry monitoring of the carbon star IRC+10216 obtained between 1999 and 2001 with the SAO 6m telescope. The J-, H-, and K-band resolutions are 50mas, 56mas, and 73mas, resp. The…
The hypergiant IRC+10420 is a unique object for the study of stellar evolution since it is the only object that is believed to be witnessed in its rapid transition from the red supergiant stage to the Wolf-Rayet phase. Its effective…
R Coronae Borealis variable stars are suspected to sporadically eject optically thick dust clouds causing, when one of them lies on the line-of-sight, a huge brightness decline in visible light. Mid-infrared interferometric observations of…
We apply mid-infrared spectro-interferometry to the massive young stellar object CRL2136. The observations were performed with the Very Large Telescope Interferometer and the MIDI instrument at a 42m baseline probing angular scales of 50…
Infrared emission from the dust shell around IRC+10216 is analysed in detail, employing a self-consistent model for radiatively driven winds around late-type stars that couples the equations of motion and radiative transfer in the dust. The…
The asymptotic giant branch (AGB) star R Sculptoris (R Scl) is one of the most extensively studied stars on the AGB. R Scl is a carbon star with a massive circumstellar shell ($M_{shell}\sim 7.3\times10^{-3}~M_{\odot}$) which is thought to…
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 polarisations, the…
We present recent polarimetric images of the highly variable star R CrB using ExPo and archival WFPC2 images from the HST. We observed R CrB during its current dramatic minimum where it decreased more than 9 mag due to the formation of an…
Using the far-infrared data obtained by the Herschel Space Observatory, we study the relation between the infrared luminosity (L_IR) and the dust temperature (T) of dusty starbursting galaxies at high redshifts (high-z). We focus on the…
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 10m and mid-infrared data extending to 32m, we have…
We obtained 13 epochs of mid-infrared interferometry with the MIDI instrument at the VLTI between April 2004 and July 2007, covering pulsation phases 0.45-0.85 within four cycles. The data are modeled with a radiative transfer model of the…
The well-known light minima of stars with the R Coronae Borealis variability are caused by the formation of an additional circumstellar dust shell, the screening shell, inside the permanent shell. Under the assumption of uniform…
From VLT/NACO diffraction-limited images of RY~Sgr, we report the first direct detection of heterogeneities in the circumstellar envelope of a R Coronae Borealis variable star. Several bright and very large dust clouds are seen in various…
We report spectra obtained with the Spitzer Space Telescope in the wavelength range between 14 microns and 35 microns of 19 nearby main-sequence stars with infrared excesses. The six stars with strong dust emission show no recognizable…
We present new imaging at 12.81 and 11.7 microns of the central ~40"x30" (~0.7x0.5 kpc) of the starburst galaxy M82. The observations were carried out with the COMICS mid-infrared (mid-IR) imager on the 8.2m Subaru telescope, and are…
CONTEXT: Simple geometrical ring models account well for near-infrared interferometric observations of dusty disks surrounding pre-main sequence stars of intermediate mass. Such models demonstrate that the dust distribution in these disks…