A closer view of our galaxy's center.By combining high resolution and high sensitivity, astronomers have produced the most revealing infrared images ever made of our galaxy's star-packed core. Using the European Southern Observatory's New Technology Telescope The New Technology Telescope, or NTT is a 3.6m telescope located at La Silla Observatory, Chile. It saw first light in 1989 and is owned by ESO. It is fitted with active optics (not to be confused with adaptive optics) allowing it to obtain an excellent image quality in La Serena, Chile La Serena ("the serene one") is the second oldest city in Chile. The city, located 471 km north of Santiago, has a population of 147,815, according to the 2002 census. There are also 12,333 inhabitants of the immediately surrounding countryside. , German researchers imaged about 340 bright stars within 1.3 light-years of the Milky Way's center, resolving features as small as 0.02 light-year across. Andreas Eckart and his colleagues at the Max Planck Institute for Extraterrestrial Physics The Max Planck Institute for Extraterrestrial Physics is a Max Planck Institute, located in Garching, near Munich, Germany. In 1991 the Max Planck Institute for Physics and Astrophysics in Garching report their findings in the April 20 ASTROPHYSICAL JOURNAL The Astrophysical Journal, often abbreviated to ApJ, is a scientific journal covering astronomy and astrophysics. It was founded in 1895 by George Ellery Hale and James E. Keeler. It currently (October 2006) publishes three issues per month, with 500 pages per issue. LETTERS. The bright stars they detected at two near-infrared wavelengths are just a hint of the total number of stars that reside at the galaxy's center. Eckart's team used infrared detectors because visible-light emissions from these stars are absorbed by surrounding dust and thus don't reach Earth. Using the new images and previous estimates of stellar velocities at the center of the galaxy, Eckart and his co-workers calculate that the heart of the Milky Way Milky Way, the galaxy of which the sun and solar system are a part, seen as a broad band of light arching across the night sky from horizon to horizon; if not blocked by the horizon, it would be seen as a circle around the entire sky. contains about 1 million stars per cubic light-year -- several hundred times the density of other star-packed regions in the galaxy. The high density could explain a puzzling feature, notes Eckart. His team identified many of the imaged stars as blue supergiants. These massive stars survive for only a few million years and thus must have been born recently in order to be seen at all. Yet the galactic center lacks the dense gas clouds needed to form new stars. The German astronomers suggest that the high rate of collisions within the densely packed star cluster star cluster, a group of stars near each other in space and resembling each other in certain characteristics that suggest a common origin for the group. Stars in the same cluster move at the same rate and in the same direction. could create the blue supergiants from existing stars. |
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