HUBBLE
VIEWS OF THREE STELLAR JETS
These
NASA Hubble Space Telescope views of gaseous jets
from three newly forming stars show a new level of
detail in the star formation process, and are
helping to solve decade-old questions about the
secrets of star birth. Jets are a common "exhaust
product" of the dynamics of star formation. They
are blasted away from a disk of gas and dust
falling onto an embryonic star.
Upper
left: This view of a protostellar object called
HH30 reveals an edge-on disk of dust encircling a
newly forming star. Light from the forming star
illuminates the top and bottom surfaces of the
disk, making them visible, while the star itself is
hidden behind the densest parts of the disk. The
reddish jet emanates from the inner region of the
disk, and possibly directly from the star itself.
Hubble's detailed view shows, for the first time,
that the jet expands for several billion miles from
the star, but then stays confined to a narrow beam.
The protostar is 450 light-years away in the
constellation Taurus.
Credit: C. Burrows (STScI & ESA), the WFPC 2
Investigation Definition Team, and
NASA
Upper
right: This view of a different and more distant
jet in object HH34 shows a remarkable beaded
structure. Once thought to be a hydrodynamic effect
(similar to shock diamonds in a jet aircraft
exhaust), this structure is actually produced by a
machine-gun-like blast of "bullets" of dense gas
ejected from the star at speeds of one-half million
miles per hour. This structure suggests the star
goes through episodic "fits" of construction where
chunks of material fall onto the star from a
surrounding disk. The protostar is 1,500 light-
years away and in the vicinity of the
Orion
Nebula,
a nearby star birth region. Credit: J. Hester
(Arizona State University), the WFPC 2
Investigation Definition Team, and
NASA
Bottom:
This view of a three trillion mile-long jet called
HH47 reveals a very complicated jet pattern that
indicates the star (hidden inside a dust cloud near
the left edge of the image) might be wobbling,
possibly caused by the gravitational pull of a
companion star. Hubble's detailed view shows that
the jet has burrowed a cavity through the dense gas
cloud and now travels at high speed into
interstellar space. Shock waves form when the jet
collides with interstellar gas, causing the jet to
glow. The white filaments on the left reflect light
from the obscured newborn star. The HH47 system is
1,500 light-years away, and lies at the edge of the
Gum
Nebula,
possibly an ancient supernova remnant which can be
seen from Earth's southern hemisphere. Credit: J.
Morse/STScI, and NASA
The
scale in the bottom left corner of each picture
represents 93 billion miles, or 1,000 times the
distance between Earth and the Sun. All images were
taken with the Wide Field Planetary Camera 2 in
visible light. The HH designation stands for
"Herbig-Haro" object -- the name for bright patches
of nebulosity which appear to be moving away from
associated protostars.
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