This paper discusses the spatial distribution of M supergiant stars in the Galaxy using infrared data from IRAS.

The Fleurs Synthesis Telescope (FST) has been used to map a number of bright, southern galactic HII regions at 1415 MHz. Descriptions of the FST can be found in Christiansen (1973) and associated papers. For the observations reported here, both the east-west and the north-south arms of the cross were used resulting in beamshapes which are nearly circular with half-power widths of 50” arc. The maps have been “cleaned” using a standard process (Högbom 1974).

There has been a great deal of progress in our understanding of planetary nebulae and their central stars during the past decade and a half. Most of this has come about through progress in observational techniques covering almost the entire electromagnetic spectrum. Theories of planetary nebula evolution have been put to better and better tests as more and more discriminating data have become available.

This review describes some of the progress made in observations and their interpretation, particularly in the context of the evolution of the nebulae and the central stars. It includes a discussion on the improved determinations of magnitudes and temperatures of the central stars, and of progress in the measurement of distances, and a reassessment of the observed mass-distribution of the central stars. The last topic has been at the centre of a lively debate for almost a decade now and has been responsible for a large number of studies of central star evolution, some this review briefly touchs upon.

This paper is based on a report given at the ASA Conference in July 1994, but takes account of subsequent developments up to the end of the year. The present state of the Two-degree Field (2dF) project for the AAT is reported. Good progress is being made on all fronts but some slippage has occurred, so that the instrument is now expected to begin astronomical observations only during the second half of 1995. An outline of other current and future instrumentation plans at the AAO is given.

Multi-frequency observations with the Culgoora radioheliograph (Wild 1967); Sheridan et al. 1973) of five solar bursts of spectral type II (Wild et al. 1954) have now been analysed. The spectra of all five bursts show split-banded harmonic structure. Each type II burst passed through only two of the heliograph’s three observing frequencies (160, 80 and 43.25 MHz). Relationships between the positions, sizes and brightness temperatures of the various sources in each burst are presented and summarized; their implications for the propagation of shock waves and radio waves in the solar corona are briefly discussed.

The LYMAN project continues the distinguished US and European tradition of the exploration of the Universe at Ultraviolet Wavelengths accessible only from space. These earlier missions, which include OAO, TD-1, ANS, Copernicus and the International Ultraviolet Explorer (IUE), each demonstrated the existence of new and hitherto unsuspected physical phenomena and processes, and have collectively enhanced our understanding of the evolution of stars, galaxies and the Universe.

The importance of both the UV-spectral region as a cornerstone of astronomical research, and of an observatory mode of operation is apparent when it is noted that observations from the IUE satellite are now cited more often than observations from any earth- or sky- based observatory. However, IUE is not eternal, and LYMAN is the next step forward, pushing the sensitivity limit down by a factor of more than 100, and opening up new fields and wavelengths of study. LYMAN is planned as a grazing incidence Wolter-Schwartzschild Type II telescope with an aperture of 80cm, feeding an array of sensitive far-UV and EUV spectrographs equipped with Photon Counting Array (PCA) detectors.

On 1922 August 20, a 20-strong scientific team, together with a naval party of 10, left Fremantle on one of the major scientific expeditions in Western Australian history. After picking up further personnel at Broome, the party proceeded to the isolated post and telegraph station of Wallal on the northern coast of Western Australia. Their task was to measure with great care the deflection of starlight by the Sun during the total solar eclipse of 1922 September 21. Specially designed photographic equipment of very high quality was used and meteorological conditions were excellent. As a result, measurements were obtained for well over a hundred stars.

A recent measurement of muon flux at energies greater than 1012 eV provides evidence for muon production by a process other than pion decay in cosmic-ray showers. Near this characteristic energy, the existing theory of weak interactions requires modification if it is not to violate a limitation (2) imposed by unitarity, which represents the conservation of probability. This work is an examination of modifications that are needed if the framework (4) of the theory is to be retained.

Infrared astronomical observations using ground-based equipment are confined to the few ‘windows’ or observation ports allowed by our absorbing atmosphere, the chief absorbing molecules being water vapour and CO2 . The majority of such observations have been made using broadband filters defining the photometric J, H, K, L, M, N and O bands. Some narrow band and spectral work (essentially all photometric) has also been carried out, particularly in the 8-14 micron window. From a very few high altitude, cold, dry sites (where the integrated water vapour content of the atmosphere above the site is consistently less than 1mm), it is possible to make observations at 35 and 345 microns. In Australia, the integrated water vapour content above us is typically 15 mm, only rarely dropping below 7 mm, so that long wavelength IR measurements simply cannot be made using ground-based instruments in Australia. Water vapour is fortunately not well mixed in our atmosphere and by raising our observational platform to a high enough altitude we can in fact achieve quite high transmission for all wavelengths from 10 microns to 1 mm, where we link up with microwave observations using essentially radio techniques.

It is well known that a magnetic field has an inhibiting effect on thermal convection. It is also likely that a magnetic field might have a marked effect on the preferred cell-size and it is therefore of some importance to investigate the effect of such a field on finite amplitude convection. We restrict ourselves to fluids in which the Boussinesq approximation holds. For astrophysical application, especially in a study of the convective layer of the Sun, one should consider the compressible case but unfortunately the full compressible equations are much more difficult to handle numerically. In any case, the integration of the equations for the incompressible case will yield at least an indication of the effect of a magnetic field.

Zeldovich and Guseynov suggested that neutron stars and collapsed stars (‘Black holes’) may be found as highly evolved companions of single lined spectroscopic binaries. They pointed out that the detection of X-rays or γ-rays from such a system would constitute positive evidence for the highly evolved nature of the companion. Trimble and Thorne searched through the catalogue of orbital elements of spectroscopic binaries (Batten) and found a few systems which were single line spectroscopic binaries with companions of mass M2 ≥ (1.4 M⊙, M1 ), where M1 is the primary mass. None of these has, however been identified with an X-ray source and other explanations such as multiple systems could not be ruled out. The alternative procedure, namely the identification of galactic X-ray sources with spectroscopic binaries is clearly more rewarding from the view point of searching for black holes and neutron stars. In particular, a high mass secondary which could be identified with a black hole is more likely to be discovered as a companion of an X-ray binary with a massive primary such as a blue supergiant.

In this paper, two models for the origin of modulation lanes in Jovian radiation are discussed. The results of calculations of dynamic spectra due to the Cotton-Mouton effect in Jupiter’s plasma envelope and due to modulation of the frequency spectrum in the source are reproduced. The characteristics of the theoretical spectra are then described. This offers the possibility of solving the problem of modulation lanes by comparison of observed Jovian dynamic spectra with the theoretical ones.

The eclipsing variable SV Cen was observed differentially in the UBV system with the 60cm reflector at Perth Observatory (1974-75) and with the 41cm reflector at Siding Spring (1975-79). Individual measurements have either been published in the IBVS or will be published there soon.

Molecular ices are a common component of the dust in many molecular clouds and circumstellar shells. The most abundant molecule, H2O, has several infrared spectral features which have strongly temperature dependent shapes (FWHM) and peak wavelengths. This paper describes how a study of these features, both astronomically and in the laboratory, can lead to constraints on the temperatures of interstellar dust grains. This is demonstrated in part by comparing several astronomical spectra with laboratory spectra of H2O ice.

As part of a general investigation of interstellar clouds associated with southern HII regions we have begun a high-resolution study of the sodium D-line absorption in the directions of early-type stars that are likely to be associated with or located behind the clouds.

In astrophysics the polytropic law with index n is commonly used as a means of imposing a simple and ordered physical structure on a gaseous (or smoothed discrete) system. In many instances it would be preferable to be able to introduce a polytropic density variation analytically into the basic theory rather than numerically at the computational phase. It is perhaps unfortunate that the three well known classical analytical E type solutions of the Lane-Emden equation for n = 0, 1 and 5 all have some constraining physical features; specifically, the polytrope n = 0 has uniform density and hence arbitrary radius, when n = 1 the mass and radius are independent of each other and the solution cannot be transformed homologically, and because the first zero ξ1 = ∞ for n = 5 the corresponding polytropic model has infinite extent and central condensation. In contrast, and unlike most stars, the two finite radius models have central condensations which ~ 1.