[meteorite-list] Dawn Identifies Age of Ceres' Brightest Area

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Mon, 20 Mar 2017 13:08:25 -0700 (PDT)
Message-ID: <201703202008.v2KK8PGZ000427_at_zagami.jpl.nasa.gov>

https://www.jpl.nasa.gov/news/news.php?feature=6766

Dawn Identifies Age of Ceres' Brightest Area
Jet Propulsion Laboratory
March 8, 2017

The bright central area of Ceres' Occator Crater, known as Cerealia Facula,
is approximately 30 million years younger than the crater in which it
lies, according to a new study in the Astronomical Journal. Scientists
used data from NASA's Dawn spacecraft to analyze Occator's central dome
in detail, concluding that this intriguing bright feature on the dwarf
planet is only about 4 million years old -- quite recent in terms of geological
history.

Researchers led by Andreas Nathues at the Max Planck Institute for Solar
System Research (MPS) in Gottingen, Germany, analyzed data from two instruments
on board NASA's Dawn spacecraft: the framing camera, and the visible and
infrared mapping spectrometer.

The new study supports earlier interpretations from the Dawn team that
this reflective material -- comprising the brightest area on all of Ceres
-- is made of carbonate salts, although it did not confirm a particular
type of carbonate previously identified. The secondary, smaller bright
areas of Occator, called Vinalia Faculae, are comprised of a mixture of
carbonates and dark material, the study authors wrote.

New evidence also suggests that Occator's bright dome likely rose in a
process that took place over a long period of time, rather than forming
in a single event. They believe the initial trigger was the impact that
dug out the crater itself, causing briny liquid to rise closer to the
surface. Water and dissolved gases, such as carbon dioxide and methane,
came up and created a vent system. These rising gases also could have
forced carbonate-rich materials to ascend toward the surface. During this
period, the bright material would have erupted through fractures, eventually
forming the dome that we see today.

Read more from MPS

The spacecraft is currently on its way to a high-altitude orbit of 12,400
miles (20,000 kilometers), and to a different orbital plane. In late spring,
Dawn will view Ceres in "opposition," with the sun directly behind the
spacecraft. By measuring details of the brightness of the salt deposits
in this new geometry, scientists may gain even more insights into these
captivating bright areas.

The Dawn mission is managed by JPL for NASA's Science Mission Directorate
in Washington. Dawn is a project of the directorate's Discovery Program,
managed by NASA's Marshall Space Flight Center in Huntsville, Alabama.
UCLA is responsible for overall Dawn mission science. Orbital ATK Inc.,
in Dulles, Virginia, designed and built the spacecraft. The German Aerospace
Center, Max Planck Institute for Solar System Research, Italian Space
Agency and Italian National Astrophysical Institute are international
partners on the mission team. For a complete list of mission participants,
visit:

http://dawn.jpl.nasa.gov/mission

More information about Dawn is available at the following sites:

http://www.nasa.gov/dawn

http://dawn.jpl.nasa.gov


News Media Contact
Elizabeth Landau
Jet Propulsion Laboratory, Pasadena, Calif.
818-354-6425
elizabeth.landau at jpl.nasa.gov

2017-059
Received on Mon 20 Mar 2017 04:08:25 PM PDT