WASHINGTON,
D.C.--High-energy particles spewing out of a young star in a nearby stellar
nursery are plowing through interstellar clouds and creating a giant spiral
structure in space that looks like a glowing, rainbow-colored tornado,
scientists said today.
The
star spewing the particle jet lies 480 light-years away in a star-forming
region known as Chamaeleon I.
In
a photograph
taken with NASA's Spitzer Space Telescope, that star is actually not visible
because it is located off the upper edge of the image.
The
luminous tornado-shaped structure is known as a Herbig-Haro object and
estimated to be about 0.3 light years, or nearly 2 trillion miles, long
and shows up in the infrared.
Herbig-Haro
objects are formed when highly energized particles--usually electrons and
protons--are ejected from a young star and collide with nearby clouds of
interstellar dust and gas. The jet particles stream out of the stars at speeds
of more than 100 miles per second and heat the surrounding clouds to an
infrared glow that can be detected.
Astronomers
have known about Herbig-Haro objects for decades but have never observed one
with this unique spiral structure; this particular particle jet is known as
Herbig-Haro 49/50, or HH 49/50.
"I've
never seen anything quite like this one," said Giovanni Fazio, a physicist at
the Harvard-Smithsonian Center for Astrophysics (CfA) who was not involved in
making the discovery.
"We
were really quite stunned by it," he told SPACE.com.
As
particle jets move through the clouds, they create triangular shockwaves,
similar to the wake left behind a speeding boat.
The
reason the tornado appears multi-colored is because particles at the tip of the
jet are more excited than those nearer to the star where they are emanating
from. The excited particles radiate short-wavelength emissions, which in this
color-coded image appear blue; emissions from particles near the wide base of
the jet are longer and appear red.
Scientists
aren't sure what is behind HH 49/50's unique spiral shape. One hypothesis is
that magnetic fields in the region are somehow twisting the particle jets;
another idea is that the shockwaves are creating eddies in the dust clouds
which then glow and become visible.
Scientists
also don't know whether the star at the center of the image is associated with
HH 49/50 or not.
If
it is, then it could mean that the image actually shows HH objects from two
stars colliding with each another. The more likely option, scientists say, is
that the center star is actually located much further away and only looks like
it's associated with HH 49/50 because it happened to be in Spitzer's line of
sight when the image was taken.
The team
that made the discovery was headed by John Bally of Colorado State University.
It announced today at the 207th meeting of the American Astronomical
Society.
advertisement
