Subscribe to our free daily newsletters
. 24/7 Space News .




Subscribe to our free daily newsletters



IRON AND ICE
Long-Lasting Cryovolcanism on Dwarf Planet Ceres
by Staff Writers
Gottingen, Germany (SPX) Mar 07, 2017


This view of the whole Occator crater shows the brightly colored pit in its center and the cryovolcanic dome. The jagged mountains on the edge of the pit throw their shadows on parts of the pit. This image was taken from a distance of 1478 kilometers above the surface and has a resolution of 158 meters per pixel. Image courtesy NASA/JPL-Caltech/UCLA/MPS/DLR/IDA.

Among the most striking features on the surface of Ceres are the bright spots in the center of Occator crater, which stood out already as NASA's space probe Dawn approached the dwarf planet. Scientists under the leadership of the Max Planck Institute for Solar System Research (MPS) have now for the first time determined the age of this bright material, which consists mainly of deposits of special mineral salts.

With about four million years only, these deposits are about 30 million years younger than the crater itself. This, as well as the distribution and nature of the bright material within the crater, suggests that Occator crater has been the scene of eruptive outbursts of subsurface brine over a long period and until almost recently. Ceres is thus the body closest to the Sun that shows cryovolcanic activity.

For nearly two years, the NASA's space probe Dawn has been accompanying dwarf planet Ceres, which orbits the Sun within the asteroid belt between Mars and Jupiter. During the first part of the mission, the probe advanced to lower and lower orbits until between December 2015 and September 2016 only approximately 375 kilometers separated it from the surface.

During this so-called Low Altitude Mapping Orbit the Dawn Framing Cameras produced highly resolved images of Ceres' surface displaying a resolution of 35 meters per pixel. The Dawn Framing Cameras, Dawn's scientific imaging system, were developed and built and are operated under the leadership of the MPS.

MPS researchers have now thoroughly investigated the complex geological structures that are shown in the detailed images of Occator crater. These structures include fractures, avalanches, and younger, smaller craters. "In these data, the origin and evolution of the crater as it presents itself today can be read more clearly than ever before," says Andreas Nathues, Framing Camera Lead Investigator. Additional indications were provided by measurements of the infrared spectrometer VIR onboard Dawn.

Occator crater, located in the northern hemisphere of Ceres, measures 92 kilometers in diameter. In its center a pit with a diameter of about eleven kilometers can be found. On some parts of its edges, jagged mountains and steep slopes rise up to 750 meters high. Within the pit a bright dome formed. It has a diameter of three kilometers, is 400 meters high and displays prominent fractures.

"This dome contains the brightest material on Ceres," says MPS scientist Thomas Platz. Researchers call the bright material in the central pit Cerealia Facula. VIR data show that it is rich in certain salts, so-called carbonates. Since later impacts in this area did not expose any other material from the depth, this dome possibly consists entirely of bright material.

The scattered bright spots (Vinalia Faculae) located further outside in the crater are paler, form a thinner layer and - as VIR and camera data show - turn out to be a mixture of carbonates and dark surrounding material.

Nathues and his team interpret the central pit with its rocky, jagged ridge as a remnant of a former central mountain. It formed as a result of the impact that created Occator Crater some 34 million years ago and collapsed later. The dome of bright material is much younger: only approximately four million years.

The key to determining these ages was the accurate counting and measuring of smaller craters torn by later impacts. This method's basic assumption is that surfaces showing many craters are older than those that are less strongly "perforated." Since even very small craters are visible in highly resolved images, the new study contains the most accurate dating so far.

"The age and appearance of the material surrounding the bright dome indicate that Cerealia Facula was formed by a recurring, eruptive process, which also hurled material into more outward regions of the central pit," says Nathues. "A single eruptive event is rather unlikely," he adds. A look into the Jupiter system supports this theory. The moons Callisto and Ganymede show similar domes. Researchers interpret them as volcanic deposits and thus as signs of cryovolcanism.

The MPS scientists assume that a similar process is active on Ceres. "The large impact that tore the giant Occator crater into the surface of the dwarf planet must have originally started everything and triggered the later cryovolcanic activity," says Nathues.

Following the disruption of the impact, the brine researchers suspect either as a complete layer or as scattered patches under the rocky mantel was able to move closer to the surface. The lower pressure allowed water and dissolved gases, such as methane and carbon dioxide, to escape forming a system of vents. At the surface, fractures appeared through which the saturated solution erupted from the depth. The deposited salts gradually formed the present dome.

The last of these eruptions must have created the present surface of the dome four million years ago. Whether the cryovolcanic activity has ceased completely or is ongoing on a lower level, is still unclear. Pictures of the crater showing haze when imaged at certain angles seem to speak for the latter. At the end of 2015 already, MPS researchers explained this phenomenon with the sublimation of water.

Recent investigations support this interpretation. The MPS researchers evaluated numerous images of Occator crater from an early phase of the mission taken from a distance of 14,000 kilometers and from low angles. They clearly show variations in brightness following a diurnal rhythm.

"The nature of the light scattering at the bottom of Occator differs fundamentally from that at other parts of the Ceres surface," MPS researcher Guneshwar Singh Thangjam describes the result of his analysis.

"The most likely explanation is that near the crater floor an optically thin, semi-transparent haze is formed," he adds. The researchers believe that the haze is possibly formed by sublimating water emerging from fractures in the floor of the crater when exposed to sunlight.

IRON AND ICE
Asteroid Split in Two and, Years Later, Developed Tails
Granada, Spain (SPX) Mar 03, 2017
Asteroids on the main belt, situated between Mars and Jupiter, move around the Sun in quasi circular orbits, so they do not undergo the temperature changes which, in comets, produce the characteristic tails. Nevertheless, some twenty cases have been documented of asteroids which, for various reasons, increase their glow and unfurl a tail of dust. Among the latter stands P/2016 J1, the youngest k ... read more

Related Links
Max Planck Institute For Solar System Research
Asteroid and Comet Mission News, Science and Technology


Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.

SpaceDaily Contributor
$5 Billed Once


credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly


paypal only

Comment on this article using your Disqus, Facebook, Google or Twitter login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

IRON AND ICE
India has capability to develop space station, says top official

Orion spacecraft achieves key safety milestone

The NASA Imager Dentists Use Daily

Marshall shakes, packs, ships and tracks NASA payloads

IRON AND ICE
Blue Origin shares video of New Glenn rocket

Europe launches fourth Earth monitoring satellite

Elon Musk: tech dreamer reaching for sun, moon and stars

ULA launches NROL-79 payload for NRO

IRON AND ICE
New evidence for a water-rich history on Mars

Humans May Quickly Evolve on Mars, Biologist Claims

NASA Orbiter Steers Clear of Mars Moon Phobos

Remnants of a mega-flood on Mars

IRON AND ICE
Riding an asteroid: China's next space goal

China's 1st cargo spacecraft to make three rendezvous with Tiangong-2

China to launch space station core module in 2018

Thinking Big: China Hopes to Conduct 2nd Mission to Mars by 2030

IRON AND ICE
Iridium Safety Voice Communications Installs Surge Past 500 Aircraft

Eutelsat Signs up for Blue Origin's New Glenn Launcher

Turkey Moves Closer to Launching Own Space Agency

OneWeb, Intelsat merge to advance satellite internet

IRON AND ICE
Aireon and Thales Begin Validation of Space-Based ADS-B Data

Space surveillance radar system fully operational

Coffee-ring effect leads to crystallization control

3-D printing with plants

IRON AND ICE
Hunting for giant planet analogs in our own backyard

Faraway Planet Systems Are Shaped Like the Solar System

Biochemical 'fossil' shows how life may have emerged without phosphate

The missing link in how planets form

IRON AND ICE
Juno to remain in current orbit at Jupiter

Europa Flyby Mission Moves into Design Phase

NASA receives science report on Europa lander concept

New Horizons Refines Course for Next Flyby




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News






The content herein, unless otherwise known to be public domain, are Copyright 1995-2017 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement