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Why Is The Hercules Dwarf Galaxy So Flat
Munich, Germany (SPX) Sep 18, 2007 Through some of the very first scientific observations with the brand-new Large Binocular Telescope (LBT) in Arizona, an international team of astronomers has found that a recently discovered tiny companion galaxy to our Milky Way, named the Hercules Dwarf Galaxy, has truly exceptional properties: while basically all of its known peers in the realm of these tiny dwarf galaxies are rather round, this galaxy at a distance of 430,000 Light Years appears highly flattened, either the shape of a disk or of a cigar. The stars in many large galaxies are arranged in a disk-like configuration, as in our own Milky Way. Yet in smaller galaxies like the Hercules Dwarf, which despite its name has only a 10-millionth as many stars as the Milky Way, a disk-like configuration has never been observed before. Among the millions of well-studied galaxies none has ever been observed to have a cigar-like shape. An explanation for the galaxy's unusual shape is that it is being disrupted by the gravitational forces of the Milky Way. This effect is definitely seen in another of the Milky Way's satellites, the Sagittarius Dwarf. Yet, this object is 10 times closer to the Milky Way's centre than the Hercules Dwarf Galaxy, and hence more highly affected by the destructive "tidal forces" of our Galaxy. The Hercules Dwarf Galaxy can only have experienced a similar fate if its orbit would have brought it exceptionally close to the inner parts of the Milky Way. So, "The Hercules Dwarf Galaxy is either unlike any of the millions of galaxies studied so far, or circles our Galaxy on an extremely plunging orbit: an exceptional, unparalleled object at any rate", says Matthew Coleman of the Max Planck Institute for Astronomy in Germany, who headed this study.
The world's single biggest telescope The pictures of the Hercules Dwarf Galaxy were created using the high-tech Large Binocular Camera (LBC-Blue), mounted at the Prime Focus of one of the two 8.4-metre mirrors. LBC-Blue and its future twin for the red spectral range, LBC-red, are being developed by Italian partners in the project. The camera and telescope work together like a giant digital camera which is able to capture images of ultra-faint objects with a field of view the size of the full moon. "I am delighted to see that the new camera is delivering such exciting images to the Astronomy community, off the bat," says Emanuele Giallongo of INAF/Rome, who built the camera. "We provided early 'science demonstration time' to our astronomers," says Richard Green, LBT Director, "so that they could show what can be done with this new facility. This result is just the first, with many more to come."
New chances to study distant planets, stars and galaxies The LBC camera is the first of a suite of high-tech instruments with which the LBT will be equipped in the future. These additional instruments include spectrographs with different resolution and spectral sensitivity as well as very complex instruments which will combine the light path of the two giant main mirrors. Both the telescope and instruments are being built by an international collaboration among institutions in the United States, Italy and Germany. Due to the impressive first pictures and results, the astronomers are now very confident that the $120 million project is on the way to open a new door for spectacular observations of planets, stars and galaxies. The Partners in the LBT Corporation (LBTC) are: University of Arizona, USA; Istituto Nazionale di Astrofisica, Italy; LBT Beteiligungsgesellschaft (LBTB), Germany (Max Planck Society, Astrophysical Institute Potsdam, University of Heidelberg); Ohio State University, USA; The Research Corporation, USA (University of Notre Dame, University of Minnesota and University of Virginia); The German partners are coordinated by the Max Planck Institute for Astronomy, Heidelberg, participating in 25 percent of the observation time on the LBT-Project. Community Email This Article Comment On This Article Related Links The LBT Website Stellar Chemistry, The Universe And All Within It
Coronet: A Star Formation Neighbor
Pasadena CA (SPX) Sep 18, 2007While perhaps not quite as well known as its star formation cousin of Orion, the Corona Australis region (containing, at its heart, the Coronet Cluster) is one of the nearest and most active regions of ongoing star formation. At only about 420 light years away, the Coronet is over three times closer than the Orion Nebula is to Earth. The Coronet contains a loose cluster of a few dozen young stars with a wide range of masses and at various stages of evolution, giving astronomers an opportunity to observe "protostars" simultaneously in several wavelengths. |
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