Hubble photographs mysterious rings

May 20, 1994|By New York Times News Service

The Hubble Space Telescope, taking detailed pictures of the site of an exploding star, or supernova, has confronted astronomers with a new mystery: How to explain the appearance of two thin loops of bright gases encircling the region like a pair of Hula Hoops out in space.

In describing the new Hubble pictures yesterday, Dr. Christopher Burrows, an astronomer at the Space Telescope Science Institute in Baltimore, said the rings are "are completely unlike anything we had expected to see" in the area of a supernova.

Dr. Stephen P. Maran, an astronomer at the Goddard Space Flight Center in Greenbelt, said: "It's unlike anything I have ever seen anywhere in space. Astronomers will be struggling with this mystery for years to come."

The source of this puzzlement is a picture showing the glowing debris of the supernova, designated 1987A. The supernova consists of the remnants of a star that collapsed and exploded 169,000 years ago, with the light of the event just now reaching Earth.

The supernova lies in the dwarf galaxy called the Large Magellanic Cloud, a neighbor of the Milky Way.

The Hubble picture shows three rings in all. But the smallest, which encircles the supernova, had been identified previously. The two other rings had also been seen in ground-based observations, but they were too fuzzy and obscure for interpretation. It was still not exactly clear what their positions were in relation to the supernova.

One of the curious aspects, Dr. Burrows said, was the symmetry of the two outer rings, as if one were the mirror image of the other. Each is a few light-years wide and appears to be flying out from the center.

In their first efforts to explain the phenomenon, Hubble astronomers suggested that the two rings might be part of a cosmic light show. They could be the projection of a high-energy beam of radiation or particles onto the bubble of gases that is expanding away from the exploded star. The effect would be similar to that of a searchlight sweeping across clouds.

The beam could be coming from a previously unknown stellar remnant in the vicinity, perhaps the surviving companion to the star that exploded. Hubble photography shows a dim object about one-third of a light-year from the center of the supernova explosion.

Material being drawn from the companion star, astronomers said, could fall onto the compact remnant of the exploded star, be heated and blasted back into space as narrow jets, accompanied by a beam of radiation.

If there is such a surviving companion star, astronomers said, it should collide with the supernova's expanding cloud of debris in another year or so.

From previous observations, astronomers had expected to see a bubble of gases, perhaps the shape of an hourglass, being blown into space by the exploded star.

Dr. Burrows said the rings are probably "painted" on the bubble's inner surface by the radiation beams.

One of the many mysteries, said Dr. Anne L. Kinney, another astronomer at the space telescope institute, is why the glowing rings should appear in three different places and what made them so thin.

Studies of supernovas are important to understanding the life cycles of stars, especially their deaths and the subsequent distribution of their debris in the formation of new generations of stars.

Baltimore Sun Articles
Please note the green-lined linked article text has been applied commercially without any involvement from our newsroom editors, reporters or any other editorial staff.