Perseus flasher: satellite glints.
About a year ago, a group of Canadian astronomers reportedstrange flashes of light coming from the direction of the constellation Perseus (SN: 8/23/86, p. 117). In a period of about two years approximately three dozen such bursts of light had been recorded. There are objects out somewhere in the cosmos that flash from time to time in other kinds of radiation, X-rays and gamma rays particularly. If any of the light flashes should happen to come from the same sources as the gammas and X-rays, the light flashes might contribute a good deal to understanding the astrophysics of the apparently extremely energetic processes that produce those bursts.
However, one possible source that the observers could notrule out was satellite glints, momentary reflections of sunlight by rotating artificial satellites. Two reports now attribute the observed Perseus flashes to such glints.
In a paper in the June 1 ASTROPHYSICAL JOURNAL LETTERS PaulD. Maley of the Rockwell Shuttle Operations Co. in Houston concentrates on what he calls "the main physical evidence,' a flash that occurred March 19, 1985, and was photographed from Schomberg, Ontario. According to Maley, the trajectory of the Soviet satellite Cosmos 1400 put it in the place where that flash was seen at the right time. Furthermore, a study of the optical properties of that satellite indicates that it is capable of making such glints. Maley suggests that "Earth satellites are a likely source of many isolated nonmeteoric flashes seen by ground-based observers.'
A group of 11 observers, including Maley and Bradley E.Schaefer of the NASA Goddard Space Flight Center in Greenbelt, Md., with members of the Santa Barbara (Calif.) Astronomy Group, the American Meteor Society and the Amateur Telescope Makers of Boston, comes to the same conclusion in a paper to appear in the Sept. 1 ASTROPHYSICAL JOURNAL. Similar flashes occur all over in the sky, and observers have attributed them to satellites, aircraft and even high-flying fireflies.
It has been suggested that the Perseus flasher is anastrophysical object that flashes about once every 12 hours. In this latest work, however, there were no flashes observed in 3,287.9 hours of observation of the spot in Perseus. Furthermore, a statistical analysis of the orbits and optical properties of a class of Soviet satellites called Molniyas indicates that they can account for the Perseus flashes.
However, not all light flashes from the sky have a near-earthorigin. In his paper Maley mentions three that seem to have come from a gamma-ray burst source in the supernova remnant N49. Analysis shows that these do not coincide with the known satellite population.
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|Title Annotation:||artificial satellite glints may cause flashes of light coming from direction of constellation Perseus|
|Date:||Jun 20, 1987|
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