Satellite Captures New Ultraviolet View of Young StarsThis is an ultraviolet image of Pleiades, a cluster of young stars in the constellation Taurus, visible during fall and winter in the Northern Hemisphere. The 10-degree-by-10-degree image was taken with a wide-field ultraviolet camera on board a recently launched satellite called the Midcourse Space Experiment (MSX). Seen as a tiny dipper of stars with the naked eye, the Pleiades contains about 120 stars that all formed at the same time, about 50 million years ago. The cluster (also called the Seven Sisters) spans 2 degrees of the sky in a region 7 light years in diameter and 400 light years from Earth.
Information about the research will be included in a poster paper to be presented on Tuesday, June 10, during a meeting of the American Astronomical Society. The paper will be on display from 10 a.m. to 6:30 p.m. in the South Main Hall of the Benton Convention Center in Winston-Salem. N.C. The research has been funded by the Ballistic Missile Defense Organization.
Marsha Allen, a Johns Hopkins astrophysicist, is part a team of astronomers using MSX to study these stars. The team is headed by Richard Henry, a professor in the Johns Hopkins Department of Physics and Astronomy, and Stephan Price, a scientist at the U.S. Air Force's Phillips Laboratory. Other team members are research scientist Jayant Murthy, graduate students Andrew Dring and Ryan Newcomer, all of Johns Hopkins University, and Larry Paxton of the Johns Hopkins Applied Physics Laboratory.
MSX, built by the Applied Physics Laboratory and launched in April 1996, is unusual because it is capable of taking wide-angle images of the sky in the entire spectrum from the ultraviolet to the infrared, giving astronomers a more complete picture of conditions in space.
Hot stars emit a great deal of ultraviolet radiation. Astronomers are trying to learn more about the regions in which stars form, so they are studying the nature of interstellar dust in those regions. Because the Pleiades are surrounded by dust, the light from each star is reflected by the dust particles. In photographs of the cluster taken from the ground, wispy clouds of dust, illuminated by starlight, can be seen surrounding the stars. Ultraviolet light also is reflected and scattered by the dust particles, so it can provide valuable information about the properties of the dust. Space-borne instruments must be used to make observations in the ultraviolet spectrum because those wavelengths are filtered out the Earth's atmosphere.
Note: Journalists may obtain a hard copy of the image by contacting Emil Venere, in the Johns Hopkins Office of News and Information, 410-516-7160, or by e- mail (firstname.lastname@example.org).
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