V838 Mon: Echoes from the Edge
Explanation:
Variable star V838
Monocerotis lies
near the edge of our
Milky Way Galaxy,
about 20,000 light-years
from the Sun.
Still, ever since a
sudden
outburst was detected
in January 2002, this enigmatic star has taken the center of
an
astronomical stage while
researchers
try to understand
where it fits into the picture of
stellar evolution.
As light from the stellar flash echoes across
pre-existing dust shells around V838 Mon, its appearance
changes dramatically.
Revealed in a
sharp
snapshot recorded in February by the Hubble's
Advanced Camera for Surveys,
this portion of the dust shell is about six light-years
in diameter.
But because light reflected from the dust follows only a slightly
indirect path compared to the
direct line-of-sight to the star, the
light echoes visible now
are only lagging about two years behind
the outburst itself.
Astronomers expect the
expanding
echoes to continue to light up
the dusty environs of V838 Mon for at least the rest of the
current decade.
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.
