SEATTLE - An explosive star in the Southern Hemisphere called Eta Carinae, which is at least 100 times more massive than our Sun, appears actually to be two stars working in concert. Proof may come this summer when the star is expected to act up again.

The supernova erupted magnificently in the 1800s, becoming one of the brightest stars in the night sky. It has since settled down a bit as two giant bubbles of material billow into space. In 1997, a peak of activity, seen in X-rays, was thought to be attributed to a 5.5-year cycle.

At a meeting here of the American Astronomical Society, scientists monitoring the X-rays said evidence is building for a theory that the cycle is caused by a smaller stellar companion. As the stars orbit one another, their stellar winds clash in varying ways, producing dips and peaks in X-ray emissions.

Michael Corcoran of NASA's Goddard Space Flight Center is leading the investigation. He said the smaller star seems to contain the mass of 30 suns, while the larger star is 80 times more massive than the Sun.

SEATTLE - After examining 20 years of data, astronomers say they've identified a small young star that's been tossed out of what was a three-star system, left to probably wander through space alone while its two larger and previous orbital companions remain gravitationally huddled.

The event, announced here today at a meeting of the American Astronomical Society, is the first to ever have been observed as it occurred.

The evidence, from the National Science Foundation's Very Large Array telescope, shows that the smaller star underwent a drastic change in orbit after passing close to one of its companions in the mid-1990s.

"The young star was accelerated to a large velocity by the close approach, and certainly now is in a very different, more remote orbit, and may even completely escape its companions," said Laurent Loinard of the National Autonomous University of Mexico.

SEATTLE - What might be a new type of star has been stripped of most of its mass, leaving behind a pitiful little thing astronomers called "degenerate."

The beleaguered object has been losing its bulk to a bully companion star for billions of years, fueling constant explosive activity on the more massive thief. About seven years ago, the robbery mysteriously halted, and astronomers have been able to get a better look at the smaller, dimmer object in the absence of all the radiation that had been pouring out of the two-star system called EF Eridanus.

They figure the wimpy star was once similar to our Sun, though about half as massive. Some 90 percent of its mass is now gone, however. It now looks a lot like a type of failed star called a brown dwarf, cool and not hefty enough to fuel the thermonuclear fusion that puts the shine into real stars. But brown dwarfs are suspected of forming at their present sizes from collapses of material -- not by being sculpted away by hungry companions.

The research was led by Steve Howell of the University of California, Riverside, and Tom Harrison of New Mexico State University, Las Cruces. It was presented here today at a meeting of the American Astronomical Society.

SEATTLE - Astronomers look to Heros to help them study the early universe and its expansion. These Hyper Extremely Red Objects move away from us so fast that their light is highly "redshifted." Light from objects moving away is stretched, becoming redder, whereas objects moving toward have their light waves compressed, getting bluer.

Now the first Hero has been found near a so-called radio galaxy, some 10 billion light-years away. Radio galaxies are optically dim but have strong radio emissions. The finding was announced here today at a meeting of the American Astronomical Society.

"Like comic book heroes, they travel really fast -- almost at the speed of light, said Myungshin Im of Caltech. "They are virtually invisible to our eyes and they are very mysterious. Most importantly, this type of Hero may hold a key for understanding how the first galaxies formed and evolved in the universe."

The discovery suggests radio galaxies could serve as guideposts for finding other Heros. Future space-based observations might reveal Heros to be the universe's first stars and galaxies, astronomers say.

SEATTLE - A dim and small star only twice as hot as your kitchen oven has been found about 19 light-years from Earth. The star, a so-called brown dwarf, is hardly heavier than Jupiter and does not contain enough mass to jumpstart the thermonuclear fusion that powers real stars.

The object was called the faintest star ever found. Its discovery was announced here today by Frederick Vrba of the U.S. Naval Observatory at a meeting of the American Astronomical Society. Vrba led a team that has examined the object for several months to figure out its dimensions. Weighing in between planets and stars, brown dwarfs continue to puzzle astronomers, who've known about them since the mid-1990s.

The star, called 2MASS 0415-0935, emits almost no visible light and was detected by its infrared emissions -- the same stuff that your TV remote uses to change the channels. It is about 770 degrees Fahrenheit (410 C). The Sun's surface is about 9,940 degrees Fahrenheit (5,500 C).

"It would take a half a million of these brown dwarfs to produce the same amount of light as the Sun," said UCLA researcher Adam Burgasser, who first spotted the object two years ago.

The newfound batch of stars moves collectively in a different direction and speed compared with other stars in Andromeda and appears to be gradually being absorbed. By studying these stretched out relics, astronomers hope to piece together a complete history of the ancient mergers that led to the galaxy's present configuration.

"We looked in just one narrow area of the halo and found a debris stream, which tells us there are probably many more lurking under the surface," said Puragra GuhaThakurta of the University of California, Santa Cruz.

The halo is a vast and sparsely populated sphere of stars that surrounds the main disk of the Andromeda galaxy. A similar halo surround the Milky Way, and astronomers have found star streams in it, too. Looking at Andromeda is a lot like looking at a reflected image of our own galaxy, astronomers say.

-- Astronotes by Robert Roy Britt