Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: WEDNESDAY, June 9, 1993 TAG: 9306090391
SECTION: NATIONAL/INTERNATIONAL PAGE: A4 EDITION: METRO
SOURCE: Associated Press
DATELINE: BERKELEY, CALIF. LENGTH: Medium
It's also spotted weird "naked" stars, performing what some astronomers called a "celestial strip show."
The discoveries were announced Wednesday during the American Astronomical Society's national meeting.
In December, NASA plans to launch a shuttle and seven astronauts to fix the Hubble's slightly fuzzy vision, jittery solar panels, failed gyroscopes and other problems.
The mission is so complicated, with a record five spacewalks, that "we have a lot of nightmares," said Edward Weiler, NASA's chief Hubble scientist. "There's a lot could go wrong."
Despite a mirror that was ground improperly and other mechanical problems with the $2.5 billion project, the telescope works so well that astronomers believe "the biggest problem with the Hubble is getting observing time," said Thomas Ayres of the University of Colorado at Boulder.
It recently discovered a new Researcher Guido De Marchi said gravity from stars in a cluster probably stripped 15 observed stars of their outer gas layers in what the Hubble institute called "stellar cannibalism." class of blue stars. The 15 stars apparently started as red giants, but were stripped of their outer gas layers so that only their "naked cores" remain, said Guido De Marchi, a researcher at the Space Telescope Science Institute in Baltimore.
"He appears to have uncovered a celestial strip show at the center of a dense star cluster" named M15, said Steve Maran, astronomy society spokesman.
The "naked core" stars are six times hotter than the sun.
De Marchi said gravity from other stars in the cluster probably stripped the 15 stars in what the Hubble institute called "stellar cannibalism."
Astronomer George Benedict, of the University of Texas at Austin, used the Hubble to find that Proxima Centauri, the star closest to our solar system, may be bouncing every 41 days. That suggests, but doesn't prove, that a Jupiter-sized planet orbits Proxima Centauri and makes it wobble, he said.
"It's like detecting a small, invisible kid on a teeter-totter by observing a large adult moving up and down a little bit," Benedict said.
Researchers from the Hubble institute, the Carnegie Institution and the California Institute of Technology announced what Carnegie astronomer Wendy Freedman called "a major step" in measuring the age and size of the universe and its speed of expansion.
They used Hubble to locate 30 bright, slowly pulsating stars called Cepheids in spiral galaxy M81 and measure their distance from Earth.
Because the brightness of a Cepheid is proportional to its pulse rate, scientists can determine its exact brightness and use that to estimate their distance, making it possible to use them as a cosmic yardstick, Freedman said.
Scientists often say the universe is 15 billion years old, but they really only know it is between 10 billion and 20 billion years old.
Ayres said he used the Hubble to watch a young star in the Pleiades star cluster as it produced a flare that made the star's ultraviolet brightness triple in a mere 20 minutes. The flare was 100 to 1,000 times larger than our sun's biggest flares, he said.
by CNB