Vigorous atmospheric motion in the red supergiant star Antares.

Red supergiant stars represent a late stage of the evolution of stars more massive than about nine solar masses, in which they develop complex, multi-component atmospheres. Bright spots have been detected in the atmosphere of red supergiants using interferometric imaging. Above the photosphere of a red supergiant, the molecular outer atmosphere extends up to about two stellar radii. Furthermore, the hot chromosphere (5,000 to 8,000 kelvin) and cool gas (less than 3,500 kelvin) of a red supergiant coexist at about three stellar radii. The dynamics of such complex atmospheres has been probed by ultraviolet and optical spectroscopy. The most direct approach, however, is to measure the velocity of gas at each position over the image of stars as in observations of the Sun. Here we report the mapping of the velocity field over the surface and atmosphere of the nearby red supergiant Antares. The two-dimensional velocity field map obtained from our near-infrared spectro-interferometric imaging reveals vigorous upwelling and downdrafting motions of several huge gas clumps at velocities ranging from about -20 to +20 kilometres per second in the atmosphere, which extends out to about 1.7 stellar radii. Convection alone cannot explain the observed turbulent motions and atmospheric extension, suggesting that an unidentified process is operating in the extended atmosphere.

The central dusty torus in the active nucleus of NGC 1068.

Active galactic nuclei (AGNs) display many energetic phenomena--broad emission lines, X-rays, relativistic jets, radio lobes--originating from matter falling onto a supermassive black hole. It is widely accepted that orientation effects play a major role in explaining the observational appearance of AGNs. Seen from certain directions, circum-nuclear dust clouds would block our view of the central powerhouse. Indirect evidence suggests that the dust clouds form a parsec-sized torus-shaped distribution. This explanation, however, remains unproved, as even the largest telescopes have not been able to resolve the dust structures. Here we report interferometric mid-infrared observations that spatially resolve these structures in the galaxy NGC 1068. The observations reveal warm (320 K) dust in a structure 2.1 parsec thick and 3.4 parsec in diameter, surrounding a smaller hot structure. As such a configuration of dust clouds would collapse in a time much shorter than the active phase of the AGN, this observation requires a continual input of kinetic energy to the cloud system from a source coexistent with the AGN.

Image reconstruction by the speckle-masking method.

Speckle masking is a method for reconstructing high-resolution images of general astronomical objects from stellar speckle interferograms. In speckle masking no unresolvable star is required within the isoplanatic patch of the object. We present digital applications of speckle masking to close spectroscopic double stars. The speckle interferograms were recorded with the European Southern Observatory's 3.6-m telescope. Diffraction-limited resolution (0.03 arc see) was achieved, which is about 30 times higher than the resolution of conventional astrophotography.

Astronomical speckle masking: image reconstruction by cross triple correlation.

Speckle masking is a speckle method that is capable of reconstructing true diffraction-limited images from astronomical speckle interferograms. Image degradation caused by the atmosphere and by telescope aberrations can be overcome completely. Speckle masking is a solution of the phase problem in speckle interferometry. We propose a new, modified version of speckle masking that is based on cross triple correlation processing (or cross bispectrum processing) instead of autotriple correlation processing. The advantage of cross triple correlation processing is the fact that undesired photon bias terms in the average bispectrum of the speckle interferograms are overcome completely. We show computer simulations (astronomical magnitude of ~16(m)) that illustrate the feasibility of the method.

[Histological investigations on adrenal cortex of sand rats (Psammomys obesus) during development of the diabetes mellitus (author's transl)]. / Histologische Untersuchungen an der Nebennierenrinde von Sandratten (Psammomys obesus) während der Ausbildung eines Diabetes mellitus.

The investigations were carried out on 20 sand rats (6 prediabetic, 6 diabetic and 8 normoglycemic animals). The cortices of adrenal glands were studied with histological methods. The thickness of the zona glomerulosa is in this 3 groups different. In the prediabetic group is the zona glomerulosa higher, in the diabetic group lower than the normoglycemic group. The relationship is 1.5 (normoglycemic group) : 2.9 (prediabetic group) : 0.8 (diabetic group). It is concluded that the zona glomerulosa in the prediabetic group is stimulated.

Method for measuring the average motion of a large number of biological objects.

We have developed a method for measuring the average motion of a large number of biological objects or other small particles. The moving objects are recorded on a motion-picture film. We measure optically the cross correlations between suitable pairs of motion-picture frames. These measurements yield the average motion and the histogram of the displacement vectors of the moving objects, such as Rhizobia bacteria. The motion data are useful for biological and medical studies.