BRIDGEPORT, WV (S-M) - Amateur astronomers are helping to safeguard the Hubble Space Telescope by observing a star on which professionals will soon turn the venerable instrument.
On the afternoon of November 14, astronomer Paul Szkody of the University of Washington and colleauges will attempt to use Hubble to observe a cataclysmic variable star known as SDSS091908. Astronomers hope to use the data obtained to detect pulsations in the white dwarf, as well as to determine its temperature.
"These cataclysmic variables are double stars where one component is a white dwarf, and the other is usually a red dwarf," said Contributing Editor Rigsley Berra. "What happens in these systems is that the white dwarf pulls matter from its companion star. The matter piles up on the surface of the white dwarf until it finally builds up enough pressure to start nuclear fusion. When that happens, the star increases rapidly in brightness, and we see it as a nova."
Amateur monitoring of SDSS091908 is important because if the star were to go into outburst during Hubble observations, the bright light could damage instruments on the space telescope. "The scientists will use the the Advanced Camera for Surveys to obtain ultra-violet spectra of the star," said Berra. "Meanwhile, the amateurs will watch the star to make sure it stays dimmer than magnitude 14.5 ."
The American Association of Variable Star Observers (AAVSO) is coordinating the program. "It's really great to see that even in this age of space-based billion-dollar telescopes, amateurs can still do important work in astronomy," said Berra. - GW
Copyright 2007 Starry Mirror and Glen Ward
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A white dwarf, right, draws matter from a companion star.
AMATEUR ASTRONOMERS SAFEGUARD HUBBLE - NOVEMBER 08