Searching for life and habitability in our Solar System

Main Colloquium
Dr. Geronimo Villanueva
SCHEDULED
NASA Goddard Space Flight Center, Greenbelt, USA

We recently established that Mars lost an ocean’s worth of water, while the Curiosity rover has recently detected organics on the Martian surface and in the atmosphere. Venus may have been covered by water, while organic rich oceans have been suggested to exist under the surface of Europa, Enceladus and on Titan. If these planets/moons had a rich chemical and diverse past, how much of these biomarkers were lost to space, and how much are currently available for life? Are sub-surface habitable niches connecting now with the atmosphere?  The answers to these fundamental questions of planetary evolution and habitability lie in robotic investigations of the planet’s surface and atmosphere. In the last decade, we have obtained the most comprehensive search for organic material in the Martian atmosphere and we are now sending powerful probes to Venus and beyond, permitting us to probe these planets/moons with unprecedented sensitivity. In particular, we are preparing for the human exploration of Mars, and these recent insights about Mars’ past habitability are greatly assisting us in identifying the most promising research sites. In this talk, I will present our latest discoveries with ExoMars/TGO about Mars, our exploration plans with JWST of Europa and Enceladus, and our latest findings with SOFIA and ground-based observatories of Venus, Europa and Mars.

Astrochemistry at the Cryogenic Storage Ring

SFB Colloquium
Dr. Holger Kreckel
SCHEDULED
Max-Planck-Institut für Kernphysik, Heidelberg

The Cryogenic Storage Ring (CSR) at the Max Planck Institute for Nuclear Physics in Heidelberg is the largest electrostatic storage ring project in the world. The CSR combines electrostatic ion optics with extreme vacuum and cryogenic temperatures. The storage ring has a circumference of 35 m, and all deflectors are housed in experimental vacuum chambers that can be cooled down to 5 K. It has been shown that within a few minutes of storage inside the CSR infrared-active molecular ions (e.g., CH+, HeH+ and OH-) cool to their lowest rotational quantum states by spontaneous emission of radiation. Equipped with an ion-neutral collision setup and a low-energy electron cooler, the CSR offers unique possibilities for astrochemical experiments under true interstellar conditions. I will present an overview of the capabilities of the CSR, along with first experimental results on collision experiments between cold molecular ions and neutral atoms, free electrons, and photons, yielding quantum state-selective rate coefficients for astrophysically important processes.

Magnetic fields and turbulence in molecular clouds - Observation and interpretation

Special Colloquium
Prof. Hua-bai Li
SCHEDULED
The Chinese University of Hong Kong

The Zeeman effect and dust grain alignment are two major methods for probing magnetic fields (B-fields) in molecular clouds, mainly motivated by the study of star formation, as the B-field may regulate gravitational contraction and channel turbulence velocity. I will review our recent observations of B-fields and how we interpret them with numerical simulations. We found that turbulence is sub-Alfvénic in bulk cloud volumes but can turn slightly super-Alfvénic in cloud cores due to the density enhancement. The consequences of the largely ordered cloud B-fields on fragmentation, turbulence, and star formation are observed. If time allows, I will also introduce the first direct detection of ambipolar diffusion between neutral/ion turbulent eddies.