Proposed nomenclature for Extragalactic Planetary Nebulae

The ability to identify and distinguish between the wide variety of celestial objects benefits from application of a systematic and logical nomenclature. This often includes value-added information within the naming convention which can aid in placing the object positionally either via an RA/DEC or l,b concatenation. All new nomenclatures should be created following IAU guidelines. However as the number density of specific object types on the sky increases, as in the case of PN in external galaxies, a useful positional identifier becomes problematic. This brief but timely paper attempts to progress the debate on this vexing issue for the case of extragalactic planetary nebulae (EPN). There is a clear need to rationalise the current ad-hoc system now that many thousands of Extragalactic PN are being discovered.Comment: 3 pages, no figures, LaTeX, to be published in Proceedings of the ESO workshop on Planetary Nebulae beyond the Milky Way held at ESO, Garching, May 19-21, 200

A barium-rich binary central star in Abell 70

We have found the central star of Abell 70 (PN G038.1-25.4, hereafter A 70) to be a binary consisting of a G8 IV-V secondary and a hot white dwarf. The secondary shows enhanced Ba II and Sr II features, firmly classifying it as a barium star. The nebula is found to have Type-I chemical abundances with helium and nitrogen enrichment, which combined with future abundance studies of the central star, will establish A 70 as a unique laboratory for studying s-process AGB nucleosynthesis.Comment: To be published in IAU Symp. 283: Planetary Nebulae, an Eye to the Future; 2 page

Planetariums, theatres of the Universe

The history of this magic instrument is complex, and the teaching goal was never forgotten. Technological developments of the planetarium enable it now to treat the major topics of astronomy and astrophysics. But by simplifying too much or badly, one is likely to bring confusion in the spirits. The development of the planetarium is a continual challenge, as long as the scientific culture is not integrated perfectly in the cultural landscape. In several countries, planetariums link their knowledge and their know-how, for better resisting to economic difficulties, and better speaking about astronomy to their public. In particular the great project ALMA will be celebrated in a show for the International Year of Astronomy. Today's planetarium works as a theater for all sciences, and can issue a passport to the various scales of the univers

Deep study of the galactic bulge using new planetary nebulae discovered on the AAO/UKST Ha survey

2 page(s

The Past, present and future of Galactic planetary nebula surveys

Over the last decade Galactic planetary nebula discoveries have entered a golden age due to the emergence of high sensitivity, high resolution narrow-band surveys of the Galactic plane. These have been coupled with access to complimentary, deep, multi-wavelength surveys across near-IR, mid-IR. and radio regimes in particular from both ground-based and space-based telescopes. These have provided powerful diagnostic and discovery capabilities. In this review these advances are put in the context of what has gone before, what we are uncovering now and through the window of opportunity that awaits in the future. The astrophysical potential of this brief but key phase of late stage stellar evolution is finally being realised.8 page(s

A systematic study of variability among OB-stars based on HIPPARCOS photometry

International audienceContext: Variability is a key factor for understanding the nature of the most massive stars, the OB stars. Such stars lie closest to the unstable upper limit of star formation. Aims: In terms of statistics, the data from the HIPPARCOS satellite are unique because of time coverage and uniformity. They are ideal to study variability in this large, uniform sample of OB stars. Methods: We used statistical techniques to determine an independant threshold of variability corresponding to our sample of OB stars, and then applied an automatic algorithm to search for periods in the data of stars that are located above this threshold. We separated the sample stars into 4 main categories of variability: 3 intrinsic and 1 extrinsic. The intrinsic categories are: OB main sequence stars (~2/3 of the sample), OBe stars (~10%) and OB Supergiant stars (~1/4).The extrinsic category refers to eclipsing binaries. Results: We classified about 30% of the whole sample as variable, although the fraction depends on magnitude level due to instrumental limitations. OBe stars tend to be much more variable (≈80%) than the average sample star, while OBMS stars are below average and OBSG stars are average. Types of variables include alpha Cyg, beta Cep, slowly pulsating stars and other types from the general catalog of variable stars. As for eclipsing binaries, there are relatively more contact than detached systems among the OBMS and OBe stars, and about equal numbers among OBSG stars