IRAS 17423-1755 has been recognized as a new bipolar nebula during a multi-wavelength observational program of unidentified IRAS sources with far infrared colours similar to those of known planetary nebulae. B, V, R and Hα CCD images show a clearly marked bipolar structure with a total extension of ~11 arcsec. The spectrum of the core shows strong

We present here preliminary results of an analysis of the iron abundance in the ionized gas of three planetary nebulae and one H II region of the Large Magellanic Cloud (LMC). These results are compared with the ones we obtain for a sample of Galactic and extragalactic nebulae. We find that the amounts of iron depletion into dust grains in LMC

The underlying ethos of Open Access is that the public should have the right to free access to the published results of all publicly funded academic and scientific research. Such has been the political success of OA campaigners that some funding agencies (e.g. Wellcome) now make OA publication of funded research a necessary condition for the award

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ISOPHOT is one of four instruments onboard the ESA Infrared Space Observatory scheduled for launch in September 1995. It covers the wavelength range 2.5 micrometers to 240 micrometers with wide and marrow spectral bands. Diffraction limited observations as well as wide beam measurements of faint extended sources are possible. Polarimetric

A correct modeling of the scattering polarization profiles observed in some spectral lines of diagnostic interest, the sodium doublet being one of the most important examples, requires taking hyperfine structure (HFS) and quantum interference between different J-levels into account. An atomic model suitable for taking these physical ingredients