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Light Echoes from V838 Mon
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Light Echoes from V838 Mon
Credit & Copyright: NASA, ESA, H. E. Bond (STScI)
Explanation: For reasons unknown, star V838 Mon's outer surface suddenly greatly expanded with the result that it became the brightest star in the entire Milky Way Galaxy in January 2002. Then, just as suddenly, it faded. A stellar flash like this has never been seen before. It's true that supernovae and novae expel matter out into space. But while the V838 Mon flash appears to expel material into space, what is seen here is actually an outwardly moving light echo of the bright flash. In a light echo, light from the flash is reflected by successively more distant rings in the ambient interstellar dust that already surrounded the star. V838 Mon lies about 20,000 light years away toward the constellation of Monoceros the unicorn. In this Hubble Space Telescope image from February 2004, the light echo is about six light years in diameter.

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Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)
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NASA Official: Jay Norris. Specific rights apply.
A service of: LHEA at NASA / GSFC
& Michigan Tech. U.

Based on Astronomy Picture Of the Day

Publications with keywords: light echo - v838 mon - variable star
Publications with words: light echo - v838 mon - variable star
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