NASHVILLE -- A handful of astronomers first learned about a peculiar star called V838 Monocerotis in January 2002, when an unusual outburst was detected. The larger community didn't find out about V838 Mon, as it's called, until a year later, when researchers previewed striking Hubble Space Telescope images that revealed a puzzling series of newfound shells containing gas and dust around the star.
The public saw the images in March, when they were
The concentric shells are thought to represent various previous expulsions of material being lit up in sequence as newly unleashed light from the star races outward and reflects off each shell in turn. In Nature, researchers reported that the star had brightened by 600,000 times and grew to a size equal to Jupiter's orbit around the Sun.
"Everyone with a telescope was making measurements of V838 Mon," David Lynch of the Aerospace Corporation, told astronomers gathered here today for the 202nd meeting of the American Astronomical Society. "And every measurement was a new discovery. It is the talk of astronomy."
V838 Mon most resembles a nova or supernova, stars that rapidly brighten or explode. But it is neither, several experts have said.
After the initial outburst, V838 Mon's temperature dropped from 10,340 degrees Fahrenheit to 3,140 degrees (6,000 to 2,000 Kelvin), Lynch reported. In the expelled shells, his team has found evidence of water, carbon monoxide, silicates similar to what's found in Earth's insides, and other substances in mixtures and quantities never before seen around novae or supernovae.
"It represents some of the first observations of a new kind of star, or perhaps an unusually rapid and violent stage in the star's evolution," said Catherine Venturini of Aerospace.
V838 Mon is about 20,000 light-years away. Astronomers expect to learn more in continued observations before the star fades over the next few years. Meanwhile, Lynch called it "the strangest star we have ever observed."
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