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 Long-lived storage of a photonic qubit for worldwide teleportation
12.12.2017 | Max-Planck-Institut für Quantenoptik

nachricht Telescopes team up to study giant galaxy
12.12.2017 | International Centre for Radio Astronomy Research

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: Long-lived storage of a photonic qubit for worldwide teleportation

MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.

Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

Im Focus: Successful Mechanical Testing of Nanowires

With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong

Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

Long-lived storage of a photonic qubit for worldwide teleportation

12.12.2017 | Physics and Astronomy

Multi-year submarine-canyon study challenges textbook theories about turbidity currents

12.12.2017 | Earth Sciences

Electromagnetic water cloak eliminates drag and wake

12.12.2017 | Power and Electrical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>