A duo of Chinese and American astronomers have discovered a young star
in the fierce environs of the Rosette Nebula that is ejecting a complex
jet of material riddled with knots and bow shocks.

Stripped of its normally opaque surroundings by the intense
ultraviolet radiation produced by nearby massive stars, this
young stellar object is likely one of the last of its generation
in this region of space. Its tenuous state of existence exposes
the limitations that young stars–and perhaps even sub-stellar objects
such as brown dwarfs and large planets–face in attempting to form
in such a violent environment.

A close-up image from this study of the young star, and a striking,
newly reprocessed wide-field image of the colorful Rosette Nebula,
are available at:


“Most young stars are embedded in very dense molecular clouds, which
makes our view of the early stages of star formation normally impossible
with optical telescopes,” says Travis Rector of the University of
Alaska Anchorage, co-author of a paper on the young stellar
object (YSO) in the December 2003 issue of Astrophysical Journal Letters.
“This is one of only a few cases where a protostar is visible, making it
a valuable discovery that will be studied in detail.”

Optical images of the jet taken at the WIYN 0.9-meter telescope at the
National Science Foundation’s Kitt Peak National Observatory in Arizona
a highly-collimated jet, now known as Rosette HH1, stretching for more than
8,000 astronomical units (1 AU = 150 million kilometers). It contains a
prominent knot and hints of others, which can be interpreted as “bullets”
of material being ejected from the rapidly rotating YSO at hypersonic
on the order of 2,500 kilometers per second. Bow shocks on the other side
of the YSO suggest the existence of a degenerated counterjet extending in
the opposite direction.

These interpretations of the jet were bolstered by optical spectroscopy
of the jet system taken by co-author Jin Zeng Li of the Chinese Academy
of Sciences in Beijing using the 2.16-meter telescope of the National
Astronomical Observatories of China.

“If it is indeed a counterjet, it may be the only existing observational
evidence of how bipolar jets evolve into monopoles, or at least
highly asymmetric jets,” according to Jin Zeng Li. “This suggests that
this infant star has been starved of material as its accretion disk is
evaporated, leaving a very low-mass star. In some cases, this process might
result in an isolated brown dwarf or planetary mass object, offering a
potential evolutionary solution for such lone objects that have been
spotted in the Orion Nebula and other nearby hotspots in the Milky Way.”

Located an estimated 1,500 light-years from Earth in the constellation
Monoceros, the Rosette Nebula is a spectacular region of ionized hydrogen
excavated by the strong stellar winds from hot O- and B-type stars in
the center of the young open cluster NGC 2244. It is a region of on-going
star formation with an age of about three million years.

Kitt Peak National Observatory is part of the National Optical Astronomy
Observatory, Tucson, AZ, which is operated by the Association of
Universities for Research in Astronomy (AURA), Inc., under a cooperative
agreement with the National Science Foundation.