From the observed timings of primary eclipse of HD 5303 we find that its 2.7 day period is increasing at a rate of about one second per year. In this paper we consider the implications of this in terms of mass transfer or mass loss from the system.

Four examples of dwarf galaxies apparently undergoing mass loss are discussed. All have an Hα morphology suggesting a minor axis flow. This is supported by velocity field measurements in three cases. All also have at least one compact central object, probably a young star cluster, apparently powering the flow. Some implications of these results are briefly discussed.

We present the results of an analysis of the spectra obtained for a sample of 27 Am stars. We find evidence for the presence of groups amongst these stars and argue that all Am stars exhibit a pseudo–luminosity effect.

Using a complete sample, we have looked for correlations in position between radio sources with S408 ≥ 1 Jy in the Molonglo Reference Catalogue (MRC) and rich clusters of galaxies in the Abell, Corwin and Olowin catalogue (ACO). Within a projected radius of 100 kpc of the cluster centre, we find an overdensity of radio sources similar to that seen by Robertson and Roach (1990). They attributed this feature to centrally located dominant cluster galaxies. We confirm this hypothesis by looking at the morphology of the clusters within this peak and by optically identifying galaxies associated with the radio emission. Due to the relatively high flux density limit imposed, the cluster radio sources in this sample are among the most powerful in the southern sky. The probability of a cluster containing a radio source of this power is found not to depend on cluster richness.

We have used the Parkes 64m telescope to observe the 20 → 3−1E absorption of CH3 OH at 12.2 GHz towards 58 Galactic H II regions and dark clouds, yielding 38 detections. The results show that CH3 OH absorbing clouds have a typical optical depth of 0.25 and a column density of 8.4 × 1015 cm−2. CH3 OH absorption is often accompanied by unsaturated maser emission and is closely associated with background H II regions. CH3 OH absorption against the 2.7 K background is also observed in several dark clouds.

Young supernova remnants are poorly understood and few are known. Further examples may be present, but unrecognised, within existing catalogues of radio sources. G274.68–2.84 was recently suggested as one such candidate but our new radio map from the Australia Telescope indicates that it is not a supernova remnant. Rather, it appears to be extragalactic with a strong, variable, flat-spectrum nucleus, and a bright X-ray counterpart.

The changing total luminosity of SN 1987A between 2 and 1200 days after core collapse is illustrated and discussed. From about four weeks after outburst the supernova light curve was dominated by the release of radioactive decay energy; the major contributor being 0.078M⊙ of 56Co. Recently an additional contribution probably from the decay of 57Co and 44Ti appears to be manifesting itself in the light curve. A gradually increasing fraction of the radioactive decay energy has probably been emitted at X- and γ-ray wavelengths; the fluxes are low and no recent measurements have been published. Most of the remaining radioactive decay energy appears to be emitted in the IR and is very difficult to measure. Other factors influencing the interpretation of the recent light curve are the uncertain contribution from long-lived radioactive isotopes and light-echoes. It is therefore premature to make any definitive statements on the contribution from the neutron star, although it is probably less than a few times 1037 erg s−1.

We examine the period variations of ten eclipsing binary stars and from the combined result, attempt to construct a physical explanation for their behaviour.

We present an analysis of photometry that we and others have obtained of the suspected two–hour variable K1082 in M15.

This paper summarises Ginga X-ray observations of SN 1987 A.

Spectroscopic observations of BF Cygni performed at the Haute-Provence Observatory in 1981 August, October and November are presented. The spectrum of BF Cyg was dominated by strong emission lines of H I, He I, [O III] and [Ne III]. Emission lines of He II and N III were weak. The spectrum of the star displayed dramatic variations during our observations. The intensities of Balmer lines, Balmer continuum and He I lines clearly increased from August to October, while the lines of [Ne III] and [O III] showed inverse variability.

The prompt radio emission associated with SN 1987A appeared and disappeared within the space of a few days. The next radio emission is expected as the high velocity ejecta expand into the circumstellar material. The evidence from the timing of the initial UV-flash is that this stage may occur shortly. We have therefore begun to monitor the field around SNR 1987A at high sensitivity with the Australia Telescope Compact Array. At λ6cm, an upper limit to the radio emission of 180μJy has been obtained. Continued observations are planned.

Altogether 26 new Herbig-Haro (HH) objects have been discovered by slit spectroscopy and narrow-band CCD imagery. Several of them are very remarkable in various aspects. We have also found a total of over 1000 HH candidates in L1641, L1630 and NGC 2264 on deep Schmidt plates. Fibre spectroscopy is currently underway, confirming already some 70 HH objects. Implications of this large number are briefly discussed.

This paper presents a brief discussion of the AAT data on SN 1987A and its archive.

We present UBV photometry of SW Lac and analyse its light–curve to deduce starspot parameters for this star.

A China-Japan X-ray balloon flight took place in 1988 August. Preliminary results are presented for the energy spectrum of Cyg X-1.

Air showers initiated by primary cosmic rays and gamma rays produce shower fronts which are curved. However, the arrival directions of air shower events have normally been fitted assuming a planar shower front. We present a technique which takes the average shower front shape into account to assign an improved shower direction after a first analysis assuming a plane front. We then examine the resulting angular resolution of the Buckland Park array.

Based on a new sample of (IRAS based) OH/IR stars, and a catalogue of planetary nebulae compiled by Acker (1983), we study the relation between these two groups of objects, in terms of the kinematics and the Galactic distribution. In contrast with earlier analyses of samples of OH/IR stars, we find a close correlation between the kinematics of the planetary nebulae and the IRAS based sample of OH/IR stars. In particular, we find that the distribution of the planetary nebulae (PN) shows a good correlation with the OH/IR stars which have a low outflow velocity (Vexp < 12.5 km s−1). Whether the high outflow velocity OH/IR stars also have a counterpart among PN is not clear.

We present 12CO and 13CO molecular line observations of some pre-main sequence stars associated with cometary nebulae and attempt to unravel their detailed structure.

We examine the production of cosmic ray positrons by photon-photon pair production of high-energy γ-rays on starlight photons. We start by calculating the production rate as a function of positron energy and distance from the Sun resulting from interactions with sunlight. The results are generalized to production on other types of star. We calculate the average production rate per unit volume averaged over the local region of the galaxy, and we estimate the contribution to the observed intensity from this process.