Deep Impact Captured by Gemini (Forwarded)

Gemini Observatory
Hilo, Hawaii

Tuesday, 5 July 2005

Deep Impact Captured by Gemini

The Gemini North telescope on Mauna Kea successfully captured the
dramatic fireworks display produced by the collision of NASA's Deep
Impact probe with Comet 9P/Tempel 1. Researchers in two control rooms on
Hawaii’s Big Island (on the Mauna Kea and in Hilo) were able to keep
enough composure amid an almost giddy excitement to perform a
preliminary analysis of the data. They concluded from the mid-infrared
spectroscopic observations that there was strong evidence for silicates
or rocky material exposed by the impact. Little doubt remains that the
unprecedented quality of the Gemini data will keep astronomers busy for
years.

"The properties of the mid-infrared light were completely transformed
after impact," said David Harker of the University of San Diego,
co-investigator for the research team. "In addition to brightening by a
factor of about 4, the characteristics of the mid-infrared light was
like a chameleon and within five minutes of the collision it looked like
an entirely new object." Harker’s research partner Chick Woodward of the
University of Minnesota speculated further, "We are possibly seeing
crystalline silicates which might even be similar to the beach sand here
in Hawaii! This data will keep us busy trying to figure out the size and
composition of these grains to better understand the similarities and
differences between the material contained within comets and other
bodies in the solar system."

In addition to the spectroscopic observations, before-and-after images
were also obtained by the Gemini telescope in thermal infrared light and
can be seen in Figure 1. Gemini monitored the comet for several weeks
prior to the impact and will continue to watch it through the end of July.

The Gemini observations were part of a coordinated effort between the
W.M. Keck, Subaru and Gemini Observatories so that each could
concentrate on different observations and provide a complete,
complementary "picture" of the impact. Astronomers anticipate that the
data gathered from the largest and most sophisticated set of telescopes
positioned to see the impact will add considerably to our understanding
of comets as dynamic probes of our solar system’s early evolution some
4.5-5 billion years ago.

The Gemini observations were made using Michelle, the facility
mid-infrared imager/spectrograph built at the Royal Observatory of
Edinburgh (ROE) in the UK. The instrument has unique capabilities in the
mid-infrared especially at Gemini which uses protected silver coatings
on main mirrors to provide exceptional performance in the "thermal" or
mid-infrared part of the spectrum.

Gemini is an international partnership managed by the Association of
Universities for Research in Astronomy under a cooperative agreement
with the National Science Foundation.

The Gemini Observatory provides the astronomical communities in each
partner country with state-of-the-art astronomical facilities that
allocate observing time in proportion to each country's contribution. In
addition to financial support, each country also contributes significant
scientific and technical resources. The national research agencies that
form the Gemini partnership include: the US National Science Foundation
(NSF), the UK Particle Physics and Astronomy Research Council (PPARC),
the Canadian National Research Council (NRC), the Chilean Comisión
Nacional de Investigación Cientifica y Tecnológica (CONICYT), the
Australian Research Council (ARC), the Argentinean Consejo Nacional de
Investigaciones Científicas y Técnicas (CONICET) and the Brazilian
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq).
The Observatory is managed by the Association of Universities for
Research in Astronomy, Inc. (AURA) under a cooperative agreement with
the NSF. The NSF also serves as the executive agency for the
international partnership.

IMAGE CAPTION:
[Figure 1:
http://www.gemini.edu/images/stories...12/fig1_hi.jpg
(174KB)]
Gemini North Michelle mid-infrared (11.6 micron) false-color images of
9P/Temple 10 minutes before impact (left), 3 hours after (center) and 24
hours after impact (right). Scale and orientation are the same for all
images. Note: the middle image represents a physical expanse about that
of the Big Island of Hawaii.