Scientists are agog over the brightest exploding star in 383 years

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It is little wonder, then, that within hours of 1987A's discovery, an extraordinary array of scientific brainpower and hardware was brought to bear on the celestial phenomenon. Throughout the southern hemisphere (the supernova is not visible in northern skies), in South America, Australia and South Africa, telescopes of every size were focused on the bright newcomer in the Large Magellanic Cloud. NASA promptly ordered some of its satellites to do the same. On its way to a rendezvous with Neptune in 1989, the Voyager 2 spacecraft pointed its two ultraviolet-light detectors at the supernova. The Solar Max satellite turned its attention from its primary target, the sun, to measure the gamma rays emanating from 1987A. The International Ultraviolet Explorer began measuring the supernova's ultraviolet radiation. In Japan space officials hurried a newly launched satellite through its calibration tests so that it could begin detecting X rays emitted by 1987A's hot gases.

Far below ground, in a salt mine under Lake Erie, in the Kamioka lead and zinc mine in Japan, in the Mont Blanc Tunnel linking Italy and France, and in another tunnel under Mount Elbrus in the Soviet Union, scientists carefully examined data from computer printouts. They were hoping that some of the ethereal particles called neutrinos, predicted by theory to be produced during a supernova, had penetrated the earth, leaving their trail in huge liquid- filled neutrino detectors. Astrophysicist J. Craig Wheeler, of the University of Texas in Austin, summarized the activity while addressing a hastily convened meeting of astronomers at NASA's Goddard Space Flight Center the week after the discovery, "These are frantic times."

By the end of last week scientists had already amassed more data than they could immediately analyze, confirming some theoretical predictions and making several observations that for the time being puzzled everyone. Earliest readings showed that the shell of gases expanding around 1987A was initially traveling outward at nearly 10,000 miles per second. Since then the color of the supernova has been changing from blue to red much faster than expected. "That change is five to ten times faster than other supernovas," says Robert Williams, director of the U.S.-financed Cerro Tololo Inter-Observatory in Chile. This phenomenon indicates that the rapid expansion of the shell is causing it to cool, thus shifting the wavelength of the emitted light more deeply into the red end of the visible spectrum. Also surprising was 1987A's low luminosity. "If it had lived up to its initial expectations," says Williams, "it should have increased its brightness to a magnitude of around 1 to 0." (A lower number means a brighter star; Sirius, the brightest star in the sky, has a magnitude of -1.5.) That would have made it look nearly as bright as the brightest stars in the night sky. Instead, the supernova rose only to a magnitude of 4.5 -- equivalent to that of a medium-bright star -- but then stopped and hovered around that figure.

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