Radio astronomers peer deep into the stellar nursery of the Orion Nebula

In this composite image combining GBT radio and WISE
infrared observations, the filament of ammonia molecules
appears red and Orion Nebula gas appears blue. Credit: R.
Friesen, Dunlap Institute; J. Pineda, MPIP; GBO/AUI/NSF

Astronomers have released an image of a vast filament of
star-forming gas, 1200 light-years away, in the stellar
nursery of the Orion Nebula.

The image shows ammonia molecules within a 50-light-year long
filament detected through radio observations made with the
Robert C. Byrd Green Bank Telescope in West Virginia. That
image is combined with an image of the Orion Nebula—an object
familiar to amateur and professional astronomers alike—taken
with NASA’s Wide-field Infrared Survey Explore (WISE)

“We still don’t understand in detail how large clouds of gas in
our Galaxy collapse to form new stars,” says Rachel Friesen,
one of the collaboration’s co-Principal Investigators and,
until 31 May 2017, a Dunlap Fellow at the Dunlap Institute for
Astronomy & Astrophysics, University of Toronto.

“But ammonia is an excellent tracer of dense, star-forming
gas,” says Friesen, “and these large ammonia maps will allow us
to track the motions and temperature of the densest gas. This
is critical to assessing whether gas clouds and filaments are
stable, or are undergoing collapse on their way to forming new

The image accompanies the first release of results from the
collaboration’s Green Bank Ammonia Survey (GAS), published in
the Astrophysical Journal. The collaboration’s other
co-Principal Investigator is Jaime Pineda, from the Max Planck
Institute for Extraterrestrial Physics; the team also includes
astronomers from the University of Toronto’s Department of
Astronomy & Astrophysics and Canadian Institute for
Theoretical Astrophysics.

The goal of GAS is to survey all the major, nearby star-forming
regions in the northern half of the Gould Belt—a ring of young
stars and that circles the entire sky and
runs through the constellation Orion. The survey will
eventually provide a clearer picture over a larger portion of
the sky of the temperatures and motions of gas within these
dynamic stellar nurseries.

Additional notes:

1) The first GAS data release includes data from observations
of four Gould Belt clouds: B18 in the constellation Taurus; NGC
1333 in Perseus; L1688 in Ophiuchus; and Orion A North in

2) The 100-metre Green Bank Telescope is located in the
National Radio Quiet Zone, a 34 thousand square kilometre area
in which radio transmissions are tightly restricted. The Green
Bank Observatory (GBO) is a facility of the National Science
Foundation operated under a cooperative agreement by Associated
Universities, Inc.

Explore further:

Hidden secrets of Orion’s clouds

More information: The Green Bank Ammonia Survey (GAS):
First Results of NH3 Mapping the Gould Belt:

Journal reference: Astrophysical

Provided by:
Dunlap Institute for Astronomy & Astrophysics