Astronomical instrumentation

Abstract:

Observations of Nova Aquilae obtained from the IUE, the Anglo-Australian Telescope, and the Westerbork Synthesis Radio Telescope are discussed. Light curves for B, V, and continuum fluxes at 2800 and 1300 A are presented. Velocities obtained from line profiles indicate the presence of three main gaseous components: a high velocity gas (HVG) component found only in absorption lines on D = 29 and 35, and a medium-velocity gas (MVG) and low-velocity gas component found in emission lines and, for the MVG, in the Na I D-line absorption. A model for thermal emission from the HVG is discussed. It is suggested that ionization in the MVG was maintained by photoionization. Properties of the dust grains are studied using data from absorption in the optical and UV and from emission in the IR.

Abstract:

The authors report spectral observations of η Carinae between 8 and 13 μm which compare the central peak of the homunculus with its periphery. The spectra not only show a lower effective temperature for the outer regions but also that the grains here have a different emissivity function. This has been shown to be consistent with the presence of large grains (Mitchell \amp Robinson, 1986) and here the modelling is extended to that of a spherical core containing small grains (a \cong 0.2 μm) and a disc of larger grains (a \cong 2.0 μm); the model predictions are consistent with observations.