[meteorite-list] New Cometary Phenomenon Greets Approaching Spacecraft (EPOXI - Comet Hartley 2)

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Fri, 22 Oct 2010 16:23:46 -0700 (PDT)
Message-ID: <201010222323.o9MNNkPj020078_at_zagami.jpl.nasa.gov>

http://www.jpl.nasa.gov/news/news.cfm?release=2010-346

New Cometary Phenomenon Greets Approaching Spacecraft
Jet Propulsion Laboratory
October 21, 2010

Recent observations of comet Hartley 2 have scientists scratching their
heads, while they anticipate a flyby of the small, icy world on Nov. 4.

A phenomenon was recorded by imagers aboard NASA's Deep Impact
spacecraft from Sept. 9 to 17 during pre-planned scientific observations
of the comet. These observations, when coupled with expected images
during the closest encounter with Hartley 2 on Nov. 4, will become the
most detailed look yet at a comet's activity during its pass through the
inner-solar system.

"On Earth, cyanide is known as a deadly gas. In space it's known as one
of the most easily observed ingredients that is always present in a
comet," said Mike A'Hearn of the University of Maryland, College Park.
A'Hearn is principal of EPOXI, an extended mission that utilizes the
already "in flight" Deep Impact spacecraft. "Our observations indicate
that cyanide released by the comet increased by a factor of five over an
eight-day period in September without any increase in dust emissions,"
A'Hearn said. "We have never seen this kind of activity in a comet
before, and it could affect the quality of observations made by
astronomers on the ground."

The new phenomenon is very unlike typical cometary outbursts, which have
sudden onsets and are usually accompanied by considerable dust. It also
seems unrelated to the cyanide jets that are sometimes seen in comets.
The EPOXI science team believes that astronomers and interested
observers viewing the comet from Earth should be aware of this type of
activity when planning observations and interpreting their data.

"If observers monitoring Hartley 2 do not take into account this new
phenomenon, they could easily get the wrong picture of how the comet is
changing as it approaches and recedes from the sun," said A'Hearn.

Cyanide is a carbon-based molecule. It is believed that billions of
years ago, a bombardment of comets carried cyanide and other building
blocks of life to Earth.

The name EPOXI itself is a combination of the names for the two extended
mission components: the extrasolar planet observations, called
Extrasolar Planet Observations and Characterization (EPOCh), and the
flyby of comet Hartley 2, called the Deep Impact Extended Investigation
(DIXI). The spacecraft will continue to be referred to as "Deep Impact."

NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the EPOXI
mission for NASA's Science Mission Directorate, Washington. The
University of Maryland, College Park, is home to the mission's principal
investigator, Michael A'Hearn. Drake Deming of NASA's Goddard Space
Flight Center, Greenbelt, Md., is the science lead for the mission's
extrasolar planet observations. The spacecraft was built for NASA by
Ball Aerospace & Technologies Corp., Boulder, Colo.

For more information about EPOXI visit http://epoxi.umd.edu/.

DC Agle 818-393-9011
Jet Propulsion Laboratory, Pasadena, Calif.
agle at jpl.nasa.gov

2010-346
Received on Fri 22 Oct 2010 07:23:46 PM PDT