Lectures

Fall Term

Courses Fall Term 2012:

September 17, 2012 - December 21, 2012

The lectures can be found on KSL: 

 KSL

Praktikum and Lecture Notes

Informations about the Physics beginner practical course can be found on the following Page.

 Physics beginner practical course (Prof. Dr. Wurz Peter)

Current Bachelor Thesis Projects

1. The dynamics of astroids during the formation of Jupiter

In the astroid belt between Mars and Jupiter, several types of astroids with similar orbits exist (Trojans, Greeks, Hildas, ..). In this bachelor thesis we study whether these dynamic groups form during the formation of Jupiter itself, namely at the moment when Jupiter rapidly accreted a large amount of hydrogen and helium gas to become a gas giant planet. For this, a sophisticated computer code is modified that numerically integrates the orbits of thousands of astroids under the gravitational influence of the forming Jupiter and the Sun. This not only yields a prediction about the resulting asteroid groups, but also about the enrichment of Jupiter in elements besides hydrogen and helium, because many asteroids collide with Jupiter enriching its atmosphere. These predictions are then compared with the observational data on the astroid families and Jupiter's composition. This will allow us to understand at which rate Jupiter accreted gas, and at which position this planet formed.

An animation to this project can be found here (proto-Jupiter is at coordinates 5,0): 
https://www.dropbox.com/s/4bponjiwucglzrj/Distrtibution.mov?dl=0

Contact:  christoph.mordasini(at)space.unibe.ch

2. Flashes from extrasolar impacts

In this thesis we study the fate of large bodies (planetesimals, asteroids) that impact into the atmosphere of a forming extrasolar giant planet. We study how they loose their mass and energy while they fly into the denser parts of the gaseous envelope. This is similar to atmospheric impacts into Earth like the Chelyabinsk meteor in 2013 or the impact of comet Shoemaker Levy 9 into Jupiter in 1994. We then study how the planet itself reacts to this massive impact, including the possible formation of an impact plume (similar to an "Atompilz"). Finally we investigate whether these impact flashes could be detected from Earth.

Dash cam videos of the Chelyabinsk meteor:
 https://www.youtube.com/watch?v=dpmXyJrs7iU

Contact:  christoph.mordasini(at)space.unibe.ch

3. Formation of planets in massive infalling protoplanetary disks

 

When a star forms, not all infalling gas can directly fall onto the star because of angular momentum conservation. Instead it first falls onto a protoplanetary disk. During the main infall phase that forms the star, the mass of this disk can become so high that it becomes unstable to its own gravity. The disk then fragments into bound clumps of gas. In this batchelor thesis we investigate when such bound clumps can form and whether they are the progenitors of gaseous giant planets. We study this by simulating the formation and evolution of a disk with a numerical model. We then check when and where the simulated disk becomes unstable, and compare the resulting clumps with the observed extrasolar planets.

Contact:  christoph.mordasini(at)space.unibe.ch

4. Comparison of the planetary population around M dwarf: theory vs observation

Stars with a mass clearly smaller than the Sun are called M dwarfs. These red stars outnumber solar-like stars by about a factor 10 in the local milky way. The population of planets around these stars is however still not well known. In this work we compare the properties of planets around M dwarfs (like their occurrence rate, their mass, their distance from the star etc.) as predicted by a theoretical model of planet formation with observations that have been obtained in the past few years by the NASA Kepler satellite. This allows to find out how well our theoretical model reproduces the observations, and where it has its shortcomings.

Contact:  christoph.mordasini(at)space.unibe.ch

5. Edelgase in Eisenmeteoriten

Edelgasmassenspektrometrie ist die momentan sensitivste Analysenmethode, typische Nachweisgrenzen liegen im Bereich von ppt (10-12g/g) oder darunter. Wir haben nun eines unserer Edelgasmassenspektrometer mit einem Laserablationssystem verbunden, um die guten Nachweisgrenzen mit einer hohen Ortsauflösung zu kombinieren. Dieses System wird momentan ausserordentlich erfolgreich für Mineralseparate aus Steinmeteoriten verwendet. Im Rahmen der Bachelorarbeit soll nun das Verfahren auf eisenreiche Minerale aus Eisenmeteoriten angewendet werden. Ziel ist es, He, Ne, Ar, Kr, und Xe-Isotope in Troilit (FeS), einem wichtigen Mineral in vielen Eisenmeteoriten, zu messen. Die Ergebnisse der Xe-Messungen werden uns dabei helfen quantitative Aussagen über die Konstanz der kosmischen Teilchenstrahlung zu machen.

Ansprechpartner: Prof. I. Leya, Parkterrasse 331a, Tel 4413,
Email:  Ingo.Leya(at)space.unibe.ch

6. ILENA

Die Gruppe von Prof. Peter Wurz hat in den letzten Jahren ein einzigartiges Konzept entwickelt, um niederenergetische neutrale Teilchen im Weltraum zu messen. Das Hauptproblem im Nachweis von diesen neutralen Teilchen ist es, dass die Teilchen zuerst ionisiert werden müssen, bevor sie analysiert werden können, und die Bedingungen an Bord eines Satelliten stellen dabei ganz besondere technologische Herausforderungen. Die Lösung dieses Problems ist es, die neutralen Teilchen mittels Stossionisation bei Streuung an einer Oberfläche zu ionisieren, und Instrumente, die nach diesem Konzept funktionieren, sind mittlerweile an mehreren Weltraummissionen beteiligt, wie z.B. Chandrayaan-1 (Mond, Indien), IBEX (interstellares Gas, NASA) und BepiColombo (Merkur, ESA & JAXA). Dabei hat sich gezeigt, dass das Verständnis des Streuprozesses an der Oberfläche von entscheidender Bedeutung für das Verständnis und die Leistungsdaten des gesamten Instrumentes ist.

In der Bachelorarbeit wird es nun darum gehen, den Streuprozess zwischen geeigneten Oberflächen und einfachen Atomen (H, O, ...) zu untersuchen. Dafür steht eine Anlage (ILENA) zur Verfügung, an der nach kurzer Einarbeitungszeit selbstständig gearbeitet werden kann, natürlich mit fortwährender Betreuung.

Interessierte Studenten wenden sich bitte an
Dr. André Galli ( andre.galli(at)space.unibe.ch) oder
Prof. Peter Wurz ( peter.wurz@space(at)unibe.ch).

7. Studies of elemental and isotopic composition to get an insight to age and formation processes of planetary materials

From the measurements of molecular and elemental/isotopic composition one can learn about the formation processes of the solar bodies, one can determine formation and transformation times and get an insight to possible past and current life processes on the planetary surfaces. We have designed a miniature mass spectrometer (LMS) with laser ion source that measures the chemical composition of solid materials. These can be stones, organic deposits, meteorites, or ancient fossils in minerals. LMS has also capabilities for detailed investigations of extraterrestrial samples including meteorites or sample returned from the surfaces of solar bodies by space missions. LMS is planned to be used to search for fossils on the surface of Mars.

We are looking for a talented and motivated person who enjoys experimental physics and have interest in the application of the mass spectrometric methods to study the age of meteorites, search for biomarkers or find the molecular composition of the surface deposits.

Applicants should contact:
PD Dr. Marek Tulej / Prof. Dr. Peter Wurz
Phone +41-31-631 44 26/ +41-13-631 44 19
E-Mail:  marek.tulej(at)space.unibe.ch