Light Echoes from V838 Mon
Explanation:
What caused this outburst of V838 Mon?
For reasons unknown, star
V838 Mon's
outer surface
suddenly
greatly expanded with the
result that it became one of the
brighter stars in the
Milky Way Galaxy in early 2002.
Then, just as suddenly,
it shrunk and faded.
A stellar flash
like this had never been seen before --
supernovas
and novas expel matter out into space.
Although the
V838 Mon
flash appears to expel material into space, what is seen in the
featured image from the
Hubble Space Telescope is
actually an outwardly expanding
light echo of the original
flash.
In a light echo, light from the flash is
reflected by successively more distant surfaces
in the complex array of ambient
interstellar dust that already surrounded the star.
V838 Mon lies about 20,000
light years away toward the
constellation of the
unicorn
(Monoceros),
while the
light echo above spans about six light years in diameter.
Authors & editors:
Robert Nemiroff
(MTU) &
Jerry Bonnell
(USRA)
NASA Web Site Statements, Warnings,
and Disclaimers
NASA Official: Jay Norris.
Specific
rights apply.
A service of:
LHEA at
NASA /
GSFC
& Michigan Tech. U.
