Date/heure
Date(s) - 2 février 2023
13 h 00 min - 14 h 00 min
Catégories
Jeudi 02 Février 2023, 13h00, amphithéâtre du CRPG | Clara Maurel (CEREGE)
What does meteorite paleomagnetism tell us about magnetic fields in the solar nebula?
One outstanding challenge in planetary sciences is to understand how km-size planetary bodies (planetesimals) form out of mm-size dust grains in protoplanetary disks. Intuitively, one could expect that planetesimals grow by gradual accretion of smaller objects. In reality, the limited effect on meter-size objects of forces normally enhancing accretion (i.e., electrostatic forces and gravity) and their fast drift towards the central star make this scenario implausible. In this context, magnetic fields present in protoplanetary disks are increasingly regarded as an alternative force acting upon the accretion of planetesimals. However, emerging accretion models that include magnetic effects remain largely unconstrained. Astronomical observations of extrasolar disk magnetic fields are extremely limited, because current technology only allows us to probe exceptionally strong fields with a poor spatial resolution. Fortunately, paleomagnetic studies of meteorites give us access to a record of the magnetic field of a protoplanetary disk (our own solar nebula) with temporal and spatial resolution far superior to those of astronomical observations. I will give an overview of our current knowledge of the solar nebula field as recorded by meteorites. As a case study, I will also present the results of our recent paleomagnetic investigation of the Erg Chech 002 meteorite, which provides us with one of the oldest and best resolved record.