Clemson University

Colloquium: Dr. Steve Desch, Arizona State University

THE EFFECT OF JUPITER’S FORMATION ON THE DISTRIBUTION OF REFRACTORY ELEMENTS AND INCLUSIONS IN METEORITES

Steve Desch

Arizona State University

Abstract: We present a comprehensive evolutionary model of the Sun’s protoplanetary disk, constructed to re- solve the “CAI storage problem” of meteoritics. We predict the abundances of calcium-rich, aluminum- rich inclusions (CAIs) and refractory lithophile elements under the central assumption that Jupiter’s ~30ME core formed at about 3 AU at around 0.6 Myr and opened a gap. CAIs were trapped in the pressure maximum beyond Jupiter; carbonaceous chondrites formed there. Inside Jupiter’s orbit, CAIs were depleted by aerodynamic drag; ordinary and enstatite chondrites formed there. For 16 chondrites and achondrites, we review meteoritic data on their CAI and refratory abundances and their times of formation, constrained by radiometric dating and thermal models. We predict their formation locations, finding excellent consistency with other location information (water content, as- teroid spectra and parent bodies). We predict the size of particle concentrated by turbulence for each chondrite, finding excellent matches to each chondrite’s mean chondrule diamater. These consistencies imply meteorite parent bodies assembled quickly from local materials concentrated by turbulence, and usually did not migrate far. We predict CI chondrites are depleted in refractory lithophile elements relative to the Sun, by about 12% (0.06 dex). We constrain the variation of turbulence parameter alpha in the disk and find a limited role for magnetorotational instability, favoring hydrodynamical instabilities in the outer disk, plus magnetic disk winds in the inner disk. Between 3 and 4 Myr at least, gas persisted outside Jupiter but was depleted inside it, and the solar nebula was a transition disk.

Bio : Steve Desch is a theoretical astrophysicist and professor in the School of Earth and Space Exploration at Arizona State University. He studies many aspects of star and planet formation, specializing in combining meteoritic data and astrophysical modeling. He studies the evolution of protoplanetary disks and models many planetary processes, in Kuiper Belt Objects in particular (his favorite is Haumea). He is the PI of the NASA NExSS-funded project at ASU, to characterize the geochemical cycles on exoplanets to aid in the search for life.

 

Refreshments will be served afterwards in the PandA Café.

Thursday, January 23, 2020 at 4:00pm to 5:00pm

Kinard Laboratory of Physics, G01 Kinard Lab
140 Delta Epsilon Ct., Clemson, SC 29634, USA

Notice of Non-Discrimination

Event Type

Lectures / Seminars / Speakers

Target Audience

Students, Faculty, Undergraduate, Graduate

Departments

College of Science, Physics and Astronomy

Contact Name:

Amanda Ellenburg

Contact Phone:

656-0343

Contact Email:

aellenb@clemson.edu

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