The tropopause, typically at 16 to 18 km altitude at the lower latitudes, dips down to only 8 km in the polar regions, allowing access to the cold, dry and nonturbulent lower stratosphere by tethered aerostats. These can float as high as 12 km, have long operating lifetimes, and are extremely reliable. In contrast to free-flying balloons, they can stay on station for weeks at a time, and payloads can be safely recovered for maintenance and adjustment and relaunched in a matter of hours. We propose to use such a platform, located first near Fairbanks, Alaska, and later in the Antarctic, to operate a new-technology 4 m telescope with diffraction-limited performance in the near infrared. Thanks to the low ambient temperature (~200 K), thermal emission from the optics is of the same order as that of the zodiacal light in the 2–3 μm band. Since this wavelength interval is the darkest part of the zodiacal light spectrum from optical wavelengths to 100 μm, the combination of high-resolution images and a very dark sky make it the spectral region of choice for observing galaxies, QSOs and clusters of galaxies at the formation epoch of galaxies.

We have recently discovered evidence for a population of radio-loud quasars that is reddened by dust. The dust is either along the line of sight to the quasars or is associated with the quasars. In the latter case the dust may be in molecular clouds in the quasar’s host galaxy, or in a molecular torus around the nucleus. We are planning to use 3 mm observations to search for molecular absorption lines (CO and HCO+) associated with dust at the redshift of these quasars. If any absorption systems are detected we will be able to deduce detailed information about the physical state of the molecular gas, hopefully showing which of the proposed locations of the dust is most likely.

Radio emission at centimetre and millimetre wavelengths provides a powerful tool for studying the circumstellar envelopes of evolved stars. These include stars on the asymptotic giant branch (AGB), post-AGB stars and a small number of massive M-type supergiant stars. The AGB stars and M-type supergiants are characterised by extremely high mass-loss rates. The mass loss in such an evolved star is driven by radiation pressure acting on grains which form in the outer stellar atmosphere. The grains are accelerated outwards and transfer momentum to the gas through grain–gas collisions. The outflowing dust and gas thus form an expanding circumstellar envelope through which matter flows from the star to the interstellar medium, at a typical velocity of 15 km s−1. For a recent review of circumstellar mass loss see Chapman, Habing & Killeen (1995).

The Center for Astrophysical Research in Antarctica conducts various educational outreach programs as part of its mission as a National Science Foundation Science and Technology Center. The method behind the outreach programs is one of forging partnerships between Center researchers and other educational organisations. The main program serves primary and secondary students in Chicago. The core of the program is called Space Explorers and is targeted at high school students. These students attend a summer residential institute at the University of Chicago’s Yerkes Observatory. The high school Space Explorers then extend the reach of the program during the academic year by teaching in primary schools using a portable planetarium. The Center also pursues many other outreach activities and is in the process of forming an Antarctic Education Alliance.

There are several excellent reasons for studying the Magellanic Clouds at millimetre wavelengths with a telescope such as the AT Mopra antenna:

• The Magellanic Clouds are the nearest young, gas-rich galaxies to the Galaxy. They are therefore ideal places to study the processes which lead to star formation, and for comparing these processes with Galactic processes.

• The distances of the Clouds are well established at close to 50 kpc for the LMC and 60 kpc for the SMC.

• The Mopra beam at 2·6 mm (CO) corresponds to ~10 pc, which is comparable with the size of molecular clouds and complexes in the LMC and SMC (e.g. Rubio et al. 1993). The Mopra beam is also complementary to that obtainable at low frequencies with the AT Compact Array for continuum and HI studies (e.g. the 750 m configuration at 21 cm will give a resolution of ~12pc).

We model a massless viscous disk using smoothed particle hydrodynamics (SPH) and note that it evolves according to the Lynden-Bell & Pringle (1974) theory until a non-axisymmetric instability develops at the inner edge of the disk. This instability may have the same origin as the instability of initially axisymmetric viscous disks discussed by Lyubarskij, Postnov & Prokhorov (1994). To clarify the evolution we evolved single and double rings of particles. It is actually inconsistent with the SPH scheme to set up a single ring as an initial condition because SPH assumes a smoothed initial state. As would be expected from an SPH simulation, the ring rapidly breaks up into a band. We analyse the stability of the ring and show that the predictions are confirmed by the simulation.

The thermal emission from a cold, dense molecular cloud peaks in the far IR, and the spectrum is rich in molecular lines in the submillimetre and millimetre bands. Observation of these bands is hindered, however, by atmospheric water vapour, which absorbs the incoming radiation. Ground-based mm observations from Australia, where the atmospheric water vapour content typically contains ~10 mm precipitable (ppt) H2O, can only probe a few of the molecular transitions from the heavier molecules, such as CO, CS, HCO+ and HCN. Sub-mm observations would enable the higher rotational lines from many of these molecules to be studied, and open up other spectral features to scrutiny, such as the lines from hydrides (e.g. CaH, NH, SH) and neutral carbon at 370 and 610 μm. However, they cannot be made from Australia. While sites such as Mauna Kea, which has ~1 mm ppt H2O on the best days, open the sub-mm band to partial viewing, their utility is limited in comparison to the opportunities possible from the Antarctic Plateau. Here the column of H2O drops to 100–250 μm.

Numerical simulations suggest that colliding molecular clouds induce gravitational collapse and may be responsible for star formation. We incorporate magnetic fields in these simulations and present preliminary results of an investigation of the influence of magnetic fields on star formation via this process.

I look briefly at protostellar environments and at what information can be gained from the millimetre waveband. A short overview of the theory of protostellar environments and evidence of disks will be followed by a more detailed review of recent publications of observations of protostellar halos/disks, specifically in 3 mm.

A condensed summary of molecular cloud astrophysics is presented. Some examples of the power of combining near-IR and mm molecular line observations are given.

The processes of accretion onto the white dwarf in a cataclysmic variable are reviewed. These systems provide the most easily observable examples of accretion disks, and enable the structure of the accretion region to be studied in detail. The properties of column accretion onto magnetic cataclysmic variables are also described.

A program to observe millimetre-wave molecular transitions in a number of southern-sky molecular clouds is under way. Molecular clouds in both the Galaxy and the Magellanic Clouds are included in the sample. The aim of the program is to build a body of observational data which can be used to derive molecular abundances in southern-sky molecular clouds.

We review the models of magnetic braking for synchronously rotating magnetic cataclysmic variables, and discuss the implications of magnetic braking for orbital evolution and the upper limit to the magnetic fields (about 70 MG) of the observed AM Herculis systems.

We have carried out calculations to model the hydrogen emission line spectrum of intermediate polars with accretion disks. We show that we can explain most of the observed optical continuum and line fluxes in terms of hard and soft X-rays that originate from the accretion shocks and are reprocessed in curtains formed by magnetically channelled material.