Fitful Young Star Sputters to Maturity in the Rosette Nebula (Forwarded)

Public Affairs and Educational Outreach
National Optical Astronomy Observatory
Tucson, Arizona

For More Information:

Douglas Isbell, Public Information Officer
National Optical Astronomy Observatory
Phone: 520/318-8214
E-mail:

EMBARGOED FOR IMMEDIATE RELEASE: Thursday, January 22, 2004

RELEASE NO: NOAO 04-03

Fitful Young Star Sputters to Maturity in the Rosette Nebula

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
http://www.noao.edu/outreach/press/p...age_0403.shtml

"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 show 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 velocities 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, Ariz., which is operated by the Association of Universities
for Research in Astronomy (AURA), Inc., under a cooperative agreement with the
National Science Foundation.