The advent of new techniques to measure the global oscillation spectrum of the Sun has provided a new and powerful tool to investigate solar structure. One of the most challenging and potentially rewarding problems in contemporary astronomy is to devise techniques which will allow similar studies of other stars. This paper outlines the theory of global oscillations of late-type main-sequence stars, and summarises some of the achievements of global oscillation studies of the Sun. It then reviews the very few successful attempts that have been made to study stellar oscillations, and briefly discusses several apparently promising lines for further instrumental development.

A review is given of recent developments in the interpretation of the structure and heating of the solar corona, and of solar flares. An electric circuit model for a flaring magnetic loop is introduced, and used to discuss the closure of the current pattern. It is argued that cross-field current flow cannot be set up after a flux tube has emerged above the photosphere. The energy dissipated in a flare is attributed to a change in the inductance of the flaring loop, with the current remaining approximately constant. Emphasis is placed on the value of the resistance of the flaring loop, and on the associated inductive timescale.

The height-integrated Pedersen and Hall conductivities are calculated for the weakly ionized region of the solar atmosphere in the vicinity of a sunspot. The values obtained are much larger than previous authors have estimated. Dynamo theories for solar flares which rely on the photospheric region having a large resistance are untenable.

In an earlier paper with the same title, I showed how knowledge of the non-corotational electric potential required to support particles in corotation with the star can be used to deduce the global qualitative forms that the potential can take in axisymmetric pulsar magnetospheres, in the absence of outflowing particles. Those arguments will now be combined with work on the outflow zone to deduce qualitative features of the potential structure in the MRW2 model.

It is believed that the splitting of the SMC into two fragments and the production of the Inter-Cloud gas and the Magellanic Stream occurred in the one event 4 × 108 years ago. This event was a collision between the LMC and SMC. This time is too short for the Stream to be tidal, or be the result of stripping of the Inter-Cloud gas by a diffuse gaseous halo. It is proposed that the clouds in the Stream are the results of collisions between the Inter-Cloud gas and HVCs in the Galactic halo. A model of this process accounts for all of the observational features of the Stream. Observations of HVCs in the path of the Magellanic Clouds are used to predict the development of the Stream. The HVCs in our halo are thought to be a result of a collision of a galaxy with our Galaxy 6 × 109 years ago.

We describe a survey of metal rich K-giants at the SGP, and show how they can be used as a simple isothermal tracing population to derive the local density of matter and the component of acceleration Kz perpendicular to the galactic plane.

Spectrum analysis of video tapes of the Jupiter S bursts in the frequency range 8-24 MHz with a frequency resolution of 2 kHz and a time resolution of 0.5 ms has shown that many of the bursts with instantaneous bandwidths less than about 10 kHz and which appear single with lower resolution, are actually double in the frequency-time plane. The frequency interval between the two components varied from 6 kHz at 9 MHz to 10.5 kHz at 23 MHz, and the corresponding time intervals from 1.3 msec to 0.6 ms.

A spectrum analyser based on SAW (surface acoustic wave) devices has been developed for Jupiter, solar and pulsar observations. It has an overall frequency range of 100 MHz and a frequency resolution of 30 kHz. A complete spectrum is produced every 80 μs. It is initially being used with a 4000 dipole broadband array in the frequency range 30-130 MHz and for Jupiter observations from 8-38 MHz.

A simple circuit has been designed for reading out at TV rate the two-dimensional CCD on the Automated Patrol Telescope. Because it is controlled by a programmable Cathode Ray Tube Controller integrated circuit it is very flexible and applicable to frame transfer CCDs having a wide range of formats.

Model predictions of light changes due to non-radial stellar pulsation have been compared with the observations of light and colour changes in mid-B star variables made by Waelkens and Rufener (1985). It is concluded that these observations are consistent with the presence of low l (dipole and quadrupole) non-radial pulsations in the stars. This strengthens Waelkens and Rufener’s hypothesis that these variables may be identified with the 53 Persei stars. The differences between the model predictions for these large Q variables, which have periods in the 1 to 3 day range, and the predictions of small Q models, which apply to β Cephei variables, are explained.

The Molonglo Observatory Synthesis Telescope is being used in a continuing program of observation of known Southern active stars. By May, 1987, a total of forty-one stars had been observed and 843 MHz quiescent emission, presumably associated with the star, had been detected in nine instances. The emission from five of these stars has shown marked variation on a time-scale > 1 day.

The Molonglo Observatory synthesis telescope has been used to obtain twelve observations of a 23′ arc field containing the active star AB Dor. On each occasion, an unresolved source close to the optical position of AB Dor was observed. The source exhibits day-to-day variations of flux density, with a mean value of ∼4 mJy. The identification of the source with the star and the variations in emission are discussed.

During the second half of 1986 tests were made of a new Q-band (43 GHz) receiver designed for the Parkes radio telescope. As part of the trial observation program 12 symbiotic stars were examined for SiO maser emission. No significant new emission was detected from any of the candidates, although several previously known SiO sources (including one symbiotic star) were confirmed. We conclude that potential SiO maser action near the Mira star in most symbiotic systems is prevented by the presence of the hot companion star.

We describe bright microwave events that were first detected with the Parkes 64-m telescope at 8.4 or 22 GHz from six active-chromosphere stars. In some flares spectral data were obtained over a large frequency range from simultaneous measurements with the Parkes reflector (8.4 or 22 GHz), the Tidbinbilla interferometer (8.4 and 2.29 GHz), the Fleurs synthesis telescope (1.42 GHz) and the Molonglo Observatory synthesis telescope (0.843 GHz). Data on circular polarization were obtained from the Parkes observations at 8.4 GHz.

The stars were in a wide variety of evolutionary states, ranging from a single pre-main-sequence star (HD 36705), two RS CVn binaries (HD 127535, HD 128171), an Algol (HD 132742) and two apparently single K giants (HD 32918 and HD 196818). Their high brightness temperatures, positive spectral indices and low polarization are consistent with optically thick gyrosynchrotron emission from mildly relativistic electrons with average energies 0.5 to 3 MeV gyrating in inhomogeneous magnetic fields of 5 to 100 G.

We present UBVRI photometry of the faint and highly erratic cataclysmic variable discovered by Hawkins (1983) from a sequence of U.K. Schmidt plates. Observations using the ANU 2.3 m telescope over two nights in September 1986 show pronounced and repeatable modulation at a binary period of 108.6 min. Dramatic colour differences are evident in the folded UBVRI light curves: in the U band, a single sinusoidal peak is present, while at longer wavelengths, a second red peak dominates at a phase separation of Δϕ = 0.5. This behaviour is strongly suggestive of cyclotron emission from two magnetic accretion funnels in an AM Herculis binary system. Furthermore, the binary period lies in the narrow range of 100-115 minutes that characterizes most of the AM Herculis variables lying on the short side of the 2-3 hour period gap. We conclude therefore that the object is almost certainly a new AM Herculis system, and develop a model in which the blue and red components originate from two non-diametrically opposed cyclotron regions that are characterized by differing electron temperatures and opacities. Predictions are made regarding the linear and circular polarization properties of this important new magnetic variable.

This is a preliminary report on the first Strömgren–Hβ photometric survey of yellow supergiants in the Magellanic Clouds. Less luminous supergiants have been chosen in preference for this program in order to facilitate calculation of their physical parameters. This will not only provide a basis for future detailed spectral analysis of these stars, but will allow a better calibration of the colours derived from model atmospheres for this type of star. The colours of these stars are more affected by changes in metallicity than the hotter stars more frequently studied, and since they are also young, they reflect the metallicity of their local InterStellar Medium (ISM). If indeed the Strömgren abundance index m1 can be calibrated successfully for these stars, then their observation in any galaxy will provide the metallicity of that particular ISM. Our results show that it is important for future colours to be calculated over the range of turbulent velocities important for supergiants.

Continuum photometry of high accuracy with Strömgren u and y filters was used to observe the LMC supernova 1987a for a period of 7 days just two weeks after the outburst.

A search has been made using the Buckland Park air shower array for evidence of any excess of events from the direction of the recent supernova in the Large Magellanic Cloud. Upper limits resulting from this search and their significance are discussed in this paper.

Evolutionary calculations have been made for a star of initial mass 17.5 M⊙ in order to emulate the evolution of the precursor of SN1987A. The results give good agreement (i) with the observed properties of Sanduleak -69°202 (star 1) when the model reaches the supernova epoch, and (ii) with the observed distribution of red and blue supergiants in the LMC. Mass loss throughout the life of the star at rates reasonably consistent with observed values is required to produce these results. At the time of explosion, the supernova has a mass of only ∼ 5.4 M⊙ and it is surrounded by about 8 M⊙ of wind material in a shell of ∼0.4 pc radius.

The concept of a national centre for the analysis of archival and contemporary space astronomy data has been identified as a highly desirable objective by the Australian astronomical community for a number of years. With the approaching launch of the Hubble Space Telescope (HST), the time is now appropriate to actively pursue this objective. HST will generate a data archive of unique astrophysical significance over the course of the ≥ 20 year mission. It is essential that Australian astronomers have efficient access to this resource, both to maintain our position at the forefront of astronomical research, and to complement our major ground-based facilities (particularly the AAT and the Australia Telescope). An Australian facility would provide efficient access to HST data and also to the analysis tools and expertise necessary for utilizing the data. Archival data from other NASA and ESA missions could also be supported, and in the longer term, the facility could become the science centre for the Lyman/Quasat missions.

This paper presents the case for an Australian Space Astronomy Data Centre, reviews the astronomy missions of relevance, and addresses the role, scope and implementation timescale of the facility. Preliminary estimates are given for the resources that will be required, and possible routes for funding the centre are outlined. Above all, the report is intended as a Discussion Paper to promote further consideration of the concept and of the service that could be provided to the Australian astronomical community.