The relative importance of the stellar sources contributing to the production matrix of the heavy elements up to iron is reviewed. Three main element groups may be distinguished: (a) oxygen and the alpha-process elements; (b) the iron-peak group; (c) helium, carbon and nitrogen. Each of these is produced in stars of a different mass range and in different ways, and it is shown that an examination of metallicity-metallicity relationships can be used to constrain models of the history of star formation, stellar evolution, and the initial mass function in galaxies.

We can conclude that in the case of our local solar neighbourhood the initial Fe/O ratio was set by Type II supernovae, but that Type I½ supernovae were never important. Iron is produced by the Type I deflagration supernovae on a time-scale comparable to the infall time-scale of the gas. Carbon is produced by dredge-up in low-mass stars, but nitrogen is shown to be produced both in the stellar winds of massive stars, and in higher mass stars which give rise to the Type I planetary nebulae.

High-speed photometry of two cataclysmic variables is presented. The observations were made using a two-channel photometric system and the Mt John 0.6 or 1-m telescopes at Lake Tekapo in New Zealand. Both objects have only recently been identified as cataclysmic variables. One of the objects is a high inclination system featuring a deep eclipse in the light curve and a 5.5 hour period, while the other object, despite being relatively faint, clearly exhibits a 2.5 hour period and out of eclipse variability. Simultaneous monitoring of a nearby comparison star for this latter object was particularly beneficial, even during good photometric conditions.

A common form of wave propagation in the highly structured magnetic fields and density profiles of the solar atmosphere should be magnetohydrodynamic surface waves, i.e. waves with magnetic and velocity fields concentrated at an interface of two regions of plasma of differing properties. For example, local concentrations of equilibrium magnetic fields forming flux tubes will support these waves on their surfaces, in addition to the more commonly considered ‘body waves’ that are supported by an isolated flux tube, waves with an oscillatory radial dependence inside the tube. Mhd surface waves have recently been identified in a laboratory plasma at Sydney University (Collins, Cramer and Donnelly 1983).

Some special issues to which IUE observations have provided crucial insight are presented. The arguments leading to the definitive identification of Sk−69°202 as the progenitor of the LMC supernova are reviewed, and a preliminary determination of the reddening toward SN 1987A, based on the IUE spectra of stars 2 and 3, is discussed. Recent observations at the predicted position of the SN ultraviolet light echo are reported, and evidence, albeit circumstantial, is provided that a UV echo has been detected. Some consequences of this result are explored. The relevance of this observation lies in the fact that a UV echo, if really detected, would give direct information of the spectrum of the SN at the time of the shock breakout.

The Mount Stromio optical pulsar detection equipment is built around a commercial two-track tape recorder: one track records timing pulses, and the other the pulses from a photomultiplier (Peterson 1974). Because of the modest frequency range of the recorder, it has been necessary to introduce a scaler between the recorder and photomultiplier in order to cope with bright sources.

Two hundred and seventeen HI profiles at positions approximately 1 ° apart in the bridge region between the Small and Large Magellanic Clouds have been observed with a 15’ arc beam. Diagrams of all the profiles, lists of column densities and average radial velocities are given, together with details of the extensive Gaussian analysis needed to account for the components.

It is shown that the bridge region is most complex. (a) Two radial velocity groups, +214 and +238 km s-1, represent the actual HI bridge between the two galaxies, (b) Three other components, at mean radial velocities of +155, +177 and +195 km s-1 are seen to be integral parts of the SMC, stretching east to R. A. ~ 04h. (c) A further three components in groups at mean radial velocities +253, +272 and +293 km s-1 appear to be extensions of HI from the main body of the LMC.

Nine sets of five closely spaced observations in the lower Magellanic Stream and in the bridge region at high sensitivity supply further information about the region.

NGC 253 is the major member of the Sculptor group of galaxies. It is classified SAB(s)c by de Vaucouleurs, de Vaucouleurs and Corwin (1976) and is almost edge-on. Previous studies have revealed a peculiar velocity field near the nucleus (e.g. Ulrich 1978). The nucleus is also a moderately strong radio and infrared source (Beck et al. 1979, Klein and Emerson 1981, Elias et al. 1978, Telesco and Harper 1980, Rieke et al. 1980).

Over 600 pulsars are now known, almost all of which lie in our Galaxy. Most pulsars have periods between 0 · 1 and a few seconds, but a very important sub-class, the ‘millisecond’ pulsars, have much shorter periods. Millisecond pulsars are often in a binary orbit with another star, suggesting that their short periods are a result of accreting mass from the companion star. They are also extraordinarily good clocks, with a stability comparable to that of the best atomic clocks. This combination of extreme period stability and binary motion has led to some very important results, including the first observational evidence for gravitational radiation and the first evidence for extra-solar planetary systems. It is probable that pulsars will be used to define the long-term standard of terrestrial time. A search of the southern sky using the Parkes radio telescope has found several millisecond pulsars which will make an important contribution to these precision-timing programs.

It is shown that numerical integration of the equation of polarisation transfer for generalised Faraday rotation provides an alternative to mode-coupling theory for treating propagation through a quasi-transverse (QT) region. At a QT region, where the sign of the component of the magnetic field along the ray path reverses, the sense of circular polarisation reverses below a frequency ωt , and is unchanged above ωt . There is a long-standing difficulty in the interpretation of the polarisation of radio emission from bipolar regions on the Sun: observational and theoretical estimates of ωt appear inconsistent. The alternative approach may help resolve this difficulty.

Mare than 100 symbiotic stars are now known. A catalogue of them, complete to 1984 January 1, is presented. Finding charts are given for all examples, and optical spectra for the majority. A table summarises the observational material at X-ray, ultraviolet, infrared and radio wavelengths.

In this paper the Very High Energy (VHE) gamma-ray astronomy program at the University of Adelaide is described. VHE gamma rays with energies above ~5 × 1011eV are observed using the atmospheric Cerenkov technique. Results from the first three years observations at Woomera and the current upgrading of the telecope are described. The CANGAROO project, a collaboration between the University of Adelaide and a number of Japanese institutions, is also introduced.

Recently, Unno has proposed a new method for constructing models of convective non-grey atmospheres, making two substantial improvements to the mixing-length theory of Böhm-Vitense. His method, based on the variational technique of Glansdorff-Prigogine, enables the determination of the eddy-size and is no longer dependent on an ad hoc assumption of a constant mixing-length to scale height ratio. It also takes into account the effects of non-grey radiative transfer.

NGC 6302 is one of the highest excitation planetary nebulae known. It has an obscured central star with a temperature estimated at 430,000 K. We present here CCD images in Hα and Hβ of NGC 6302, and interpret the differences between the images as being due to extinction caused by dust within the nebula. The dust appears to be concentrated in the core, as expected from infrared observations. There is no evidence of patchy foreground extinction, although there is a slight difference in the average extinction between the eastern and western lobes of the nebula. A comparison between the Hα image and a 5 GHz map gives a dust extinction of ΔAV~3.5 to the central star. The outer contours of the 5 GHz map are not in good agreement with the optical images, and further observations at this frequency would be useful.

We question Newton’s inverse square law of universal gravitation in the light of recent, alternative formulations. In addition, we present numerical simulations of galaxy interactions which were used in an attempt to distinguish between an inverse square law and an inverse linear law. We conclude that an inverse linear relation is as compatible with the observational data on interacting galaxy systems as the inverse square law.