Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Lumpy, bumpy, fluffy and layered: a picture of Rosetta's target comet builds up

21.08.2007
Observational and theoretical studies of Comet 67P/Churyumov-Gerasimenko, the target of ESA’s Rosetta mission, are building a detailed portrait of the comet’s nucleus as it travels around the Sun.
Observations of the comet using the 8.2 m-ESO Very Large Telescope (VLT) show an irregularly-shaped object that is about 4.6 kilometres in diameter with a rotational period of 12 hours 49 minutes. Ms Cecilia Tubiana, who will be presenting results at the second European Planetary Science Congress

(EPSC) in Potsdam on Tuesday 21st August, said, “These observations were taken when the comet was approaching the furthest point from the Sun in its orbit. Rosetta will rendezvous with the comet in 2014 at a distance of about 600 million kilometres from the Sun. While a quite detailed portrait of the comet at small heliocentric distance has been drawn, a profound description of Rosetta’s target comet at large heliocentric distance is missing.”

A team of scientists, led by the Max Planck Institute for Solar System Research, observed the comet’s nucleus in June 2004, May and August 2006 and July 2007, when the comet was at least 680 million kilometres from the Sun.
Surprisingly, although the comet was not active, they found that a faint dust trail is visible in the images of the comet, extending more than 500 000 km along the comet’s orbital path. Ms Tubiana said, “We believe that this dust trail is composed of large grains that the comet shed over the

many times it has travelled along this path.

Later on Tuesday 21st at the EPSC, Dr Jérémie Lasue, of the Service d’aéronomie in France, will present results of numerical studies that describe how a comet’s nucleus changes as it travels along its orbital path.
Dr Lasue explained, ”Comets constantly evolve by ejecting material as their distance from the Sun changes and their temperature increases or falls. To land on a comet’s nucleus, you need to have a good idea of its structure, density and tensile strength. Comet 67P/Churyumov-Gerasimenko most probably has an irregular comet nucleus with crater-like depressions on its surface.

Our team has developed a three-dimensional model of the internal processes in the nucleus, allowing us to predict the thermal evolution and surface activity as the comet moves along its orbit”

Recent mission results suggest that a comet’s structure is highly stratified. Dr Lasue said, “Stardust showed that the dust ejected from the outer layers is composed of fluffy particles that can be relatively large.

These particles are rich in silicates and organics, which are the building blocks of life. Our simulations, for the first time, take into account the relationship between the impact history of the comet and the forces holding the comet’s constituents together. This technique has enabled us to reproduce and interpret the amazing layered structure and surface features that Deep Impact observed at comet 9P/Tempel 1. This is a new means to quantify the tensile strength of comet nuclei, which gives us vital information in preparing for Rosetta’s rendezvous with 67P/Churyumov-Gerasimenko.”

The teams of scientists from France and Italy in which Dr Lasue works, are developing these numerical tools to support two of Rosetta’s instruments:

VIRTIS, which will determine the composition of the ices in the comet’s nucleus as well as emitted gases and dust, and CONSERT, which will investigate the deep interior of the nucleus with radio waves.

Anita Heward | alfa
Further information:
http://www.europlanet-eu.org/index.php?option=com_content&task=view&id=101&I

More articles from Physics and Astronomy:

nachricht New NASA study improves search for habitable worlds
20.10.2017 | NASA/Goddard Space Flight Center

nachricht Physics boosts artificial intelligence methods
19.10.2017 | California Institute of Technology

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

Terahertz spectroscopy goes nano

20.10.2017 | Information Technology

Strange but true: Turning a material upside down can sometimes make it softer

20.10.2017 | Materials Sciences

NRL clarifies valley polarization for electronic and optoelectronic technologies

20.10.2017 | Interdisciplinary Research

VideoLinks
B2B-VideoLinks
More VideoLinks >>>