[meteorite-list] Rosetta Comet Outburst Captured

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu, 13 Aug 2015 17:38:09 -0700 (PDT)
Message-ID: <201508140038.t7E0c9cV026435_at_zagami.jpl.nasa.gov>

http://www.jpl.nasa.gov/news/news.php?feature=4687

Rosetta Comet Outburst Captured
Jet Propulsion Laboratory
August 11, 2015

The European Space Agency's Rosetta spacecraft has been witnessing growing
activity from comet 67P/Churyumov-Gerasimenko as the comet approaches
perihelion (its closest point to the sun during its orbit). On July 29,
while the spacecraft orbited at a distance of 116 miles (186 kilometers)
from the comet, it observed the most dramatic outburst to date. Early
science results collected during the outburst came from several instruments
aboard Rosetta, including the Double Focusing Mass Spectrometer (DFMS),
which uses NASA-built electronics. The DFMS is part of the spacecraft's
Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA) instrument.

When the outburst occurred, the spectrometer recorded dramatic changes
in the composition of outpouring gases from the comet when compared to
measurements made two days earlier. As a result of the outburst, the amount
of carbon dioxide increased by a factor of two, methane by four, and hydrogen
sulfide by seven, while the amount of water stayed almost constant.

"This first quick look at our measurements after the outburst is fascinating,"
said Kathrin Altwegg, principal investigator for the ROSINA instrument
from the University of Bern, Switzerland. "We also see hints of heavy
organic material after the outburst that might be related to the ejected
dust.

"But while it is tempting to think that we are detecting material that
may have been freed from beneath the comet's surface, it is too early
to say for certain that this is the case."

A sequence of images taken by Rosetta's scientific camera OSIRIS shows
the sudden onset of a well-defined, jet-like feature emerging from the
side of the comet's neck. The jet, the brightest seen to date, was first
recorded in an image taken at 6:24 a.m. PDT (9:24 a.m. EDT, 13:24 GMT)
on July 29, but not in an image taken 18 minutes earlier. The jet then
faded significantly in an image captured 18 minutes later. The OSIRIS
camera team estimates the material in the jet was traveling at 33 feet
per second (10 meters per second), at least.

A composite of the three images taken by Rosetta's OSIRIS is online at:

http://rosetta.jpl.nasa.gov

On Thursday, Aug. 13, the comet and Rosetta will be 116 million miles
(186 million kilometers) from the sun -- the closest to the sun they will
be in their 6.5-year orbit. In recent months, the increasing solar energy
has been warming the comet's frozen ices -- turning them to gas -- which
pours out into space, dragging dust along with it. The period around perihelion
is scientifically very important, as the intensity of the sunlight increases
and parts of the comet previously cast in years of darkness are flooded
with sunlight. The comet's general activity is expected to peak in the
weeks following perihelion.

Comets are time capsules containing primitive material left over from
the epoch when the sun and its planets formed. Rosetta's lander, Philae,
obtained the first images taken from a comet's surface and will provide
analysis of the comet's possible primordial composition. Rosetta is the
first spacecraft to witness at close proximity how a comet changes as
it is subjected to the increasing intensity of the sun's radiation. Observations
are helping scientists learn more about the origin and evolution of our
solar system and the role comets may have played in seeding Earth with
water, and perhaps even life.

Rosetta is a a European Space Agency mission with contributions from its
member states and NASA. The Jet Propulsion Laboratory, Pasadena, California,
a division of the California Institute of Technology in Pasadena, manages
the U.S. contribution of the Rosetta mission for NASA's Science Mission
Directorate in Washington. JPL also built the MIRO instrument and hosts
its principal investigator, Samuel Gulkis. The Southwest Research Institute
(San Antonio and Boulder) developed the Rosetta orbiter's IES and Alice
instruments, and hosts their principal investigators, James Burch (IES)
and Alan Stern (Alice).

For more information on the U.S. instruments aboard Rosetta, visit:

http://rosetta.jpl.nasa.gov

More information about Rosetta is available at:

http://www.esa.int/rosetta


Media Contact

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

Dwayne Brown / Laurie Cantillo
NASA Headquarters, Washington
202-358-1726 / 202-358-1077
dwayne.c.brown at nasa.gov / laura.l.cantillo at nasa.gov

Markus Bauer
European Space Agency, Noordwijk, Netherlands
011-31-71-565-6799
markus.bauer at esa.int

2015-266
Received on Thu 13 Aug 2015 08:38:09 PM PDT