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Science Imitates Art

An artistic comparison is made of Vincent van Gogh's "Starry Night" dust swirls and bloated stars with
the stellar and dust features in the region surrounding V838 Mon.

The Light Echo Around V838 Mon

Images taken in May, September, October, and December 2002 (four-panel on left) show the early stages of the forming ligh echo. This latest image (on right) taken in February 2004 by the Hubble Heritage team shows another epoch of how the light has spread through the dusty remains of the exploded star.
Visit the HST Release STScI-2003-10:
Hubble Watches Light from Mysterious Erupting Star Reverberate Through Space

In January 2002, a faint star in an obscure constellation suddenly became 600,000 times more luminous than our Sun, temporarily making it one of the brightest stars in our Milky Way galaxy. Although back to a more normal brightness, the mysterious star, called V838 Monocerotis, has continued to illuminate the dusty environs in which it lives, uncovering remarkable new features. The phenomenon, known as a "light echo," is providing astronomers with a CAT-scan-like probe of the three-dimensional structure of shells of dust surrounding an aging star.

Astronomers do not fully understand the star's original outburst. It was somewhat similar to that of a nova, a more common stellar outburst. A typical nova is a normal star that dumps hydrogen onto a compact white-dwarf companion star. The hydrogen piles up until it spontaneously explodes by nuclear fusion -- like a titanic hydrogen bomb. This exposes a searing stellar core, which has a temperature of hundreds of thousands of degrees Fahrenheit.

By contrast, V838 Monocerotis did not expel its outer layers. Instead, it grew enormously in size. Its surface temperature dropped to temperatures that were not much hotter than a light bulb. This behavior of ballooning to an immense size, but not losing its outer layers, is very unusual and completely unlike an ordinary nova explosion.

The outburst may represent a transitory stage in a star's evolution that is rarely seen. The star has some similarities to highly unstable aging stars called eruptive variables, which suddenly and unpredictably increase in brightness.