Dr. Franck Marchis
SETI Institute Principal Investigator
Dr. Franck Marchis is a Principal Investigator at the Carl Sagan Center of the SETI Institute, and also Assistant Research Astronomer at the University of California at Berkeley.
Our solar system is characterized by considerable diversity of its constituent bodies. Franck Marchis’ first involvement in the study of this diversity started in 1996 while working at the UNAM Astronomy Department in Mexico City. He made the first ground-based observations of the volcanoes on the jovian moon Io, using the first Adaptive Optics (AO) systems available on the European Southern Observatory (ESO) 3.6 m telescope at Chile’s La Silla Observatory. After a brief stay in London and four years in Chile at ESO, he completed in 2000 his PhD in France. This doctoral research described the application of adaptive optics to the study of the solar system.
He continued this explorative work at U. C. Berkeley where he had the opportunity to use the Keck 10 m telescope and its revolutionary Laser Guide Star AO system. In collaborations with astronomers of the Observatoire de Paris, he searched for, and studied moons around asteroids. In 2005, this team discovered the first triple asteroidal system composed of Sylvia, a 200-km size irregular asteroid, surrounded by two kilometer-size satellites named Romulus and Remus. The existence of multiple asteroid systems provides direct clues about the collisional past of the solar system and the formation of major planets. The direct measurement of the bulk density of an asteroid available when the moon’s orbit is well constrained give indications about the composition and distribution of material in the asteroid.
Franck is also involved in the definition of new generation of AOs for 8 - 10 m class telescopes and data processing of images, both astronomical and biological, using fluorescence microscopy. His research involves both undergraduate and graduate students, and Marchis is eager about contributing to the diversity of our science community and educating a new generation of researchers.
A Study of Multiplicity in Small Solar System Bodies
Ending years of speculation, new observational data have proven the existence of satellites of asteroids. These discoveries are an astronomical bonanza for observers and theorists alike, since they provide powerful constraints on theories of the origin of our solar system.
These discoveries have depended greatly on the development of very successful adaptive optics (AO) systems. AO systems correct in real time the blurring effect of atmospheric turbulence, providing images with an angular resolution close to the diffraction limit of the telescope. This new technology enables direct detection of companions around asteroids.
However, the sensitivity limit of the wavefront sensors of Adaptive Optic systems presently allow useful observations of only the brightest ~400 asteroids in the main-belt. Our group of collaborators, which is lead by F. Marchis, proposes to continue and extend the hunt for asteroid satellites using AO systems and innovative techniques, such as Laser Guide Star systems, now available on several 8-10m class telescopes.
In addition to a search for binary systems, we intend to characterize the orbits of new and known binary systems in detail, to infer the internal structure of the asteroids which may presently only be speculated about following spacecraft mission flybys. The orbital elements derived from the data and the stability of the orbits will be used to infer formation mechanisms of such binary systems (e. g. capture, fission, disruption, mass shedding). These in turn will help constrain the condition and the composition of the proto-planetary environment, turning this study into one of cutting edge scientific importance.
This interdisciplinary proposal involves scientists from different science and technical communities. It will link modern observational techniques and data processing of high angular resolution images to the study of the interior structure of asteroids. Furthermore, it will make possible complex ephemeris calculations.