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A Galactic Graveyard For Your Desktop
Bristol - Apr 10, 2002 An unprecedented source of planetary nebulae, the disk-like relics of elderly, dying stars, has been discovered in the southern part of our Milky Way galaxy. With about 1000 planetary nebulae found so far and many more still to be discovered, the number of aged stars in their death throes revealed by the new survey is rapidly overtaking the entire population discovered over the entire sky during the last 75 years. The cosmic graveyard is revealed in deep survey images taken in H-alpha light with the UK Schmidt Telescope at the Anglo-Australian Observatory (AAO/UKST) in New South Wales, Australia. The survey was led by Quentin Parker (Institute for Astronomy, Royal Observatory Edinburgh) and Steven Phillipps (University of Bristol) Dr. Parker will be showing the colourful new images obtained during his survey to the UK National Astronomy Meeting in Bristol on Wednesday 10 April 2002, and explaining their significance for improving our understanding of star formation and evolution. "So far we have identified 1000 new planetary nebulae from visual scans of 70 percent of the southern Galactic plane," said Parker. "This number is now increasing rapidly as the plates are systematically scrutinised by the SuperCOSMOS facility at the Royal Observatory, Edinburgh, so that more compact, fainter candidates are being found." According to Parker, the doubling of the known population of planetary nebulae will have a significant impact on many aspects of research into stellar evolution and Galactic structure. "Finding evolved planetary nebulae and their central stars can help us understand stellar evolution during the critical transition phase between the nebula and a white dwarf," he said. "There is a currently a severe paucity of observational data of evolved planetary nebulae which our new catalogue should help address." The highlights from the new sample include identification of some rare and unusual objects:
Planetary nebulae are also excellent tracers for Galactic Bulge dynamical studies because they are less affected by metallicity bias than other tracers and have strong emission lines permitting accurate velocity determinations. The AAO/UKST H-alpha Survey was carried out using a filter that reveals hot, hydrogen-rich clouds in the Galactic plane. It uses the world's largest optical interference filter for astronomy and covers a swathe approximately 20 degrees wide along the Galactic plane. This provides an unprecedented combination of coverage, resolution and sensitivity that make it superior to any previous survey of this type. Related Links The H-Alpha Survey RAS Website UK National Astronomy Meeting Website SpaceDaily Search SpaceDaily Subscribe To SpaceDaily Express
Caution -- Planetary Traffic Jam Ahead! Cambridge - Apr 04, 2002 Comet Hale-Bopp dazzled us for weeks. The Perseid meteor shower thrilled us for one night. But the world hasn't seen anything like the planetary traffic jam that's going to occur the last week of April and the first two weeks in May! |
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