Clara Maurel Receives the Competitive Stephen E. Dwornik Planetary Geoscience Best Graduate Oral Presentation Award

Tuesday, May 28, 2019

The Planetary Geology Division of the Geological Society of America selected Maurel at the 50th Lunar and Planetary Science Conference.

EAPS graduate student Clara Maurel received the Stephen E. Dwornik Planetary Geoscience Best Graduate Oral Presentation Award at the 50th Lunar and Planetary Science Conference. The Dwornik Awards, which include presentations and posters, have become the preeminent award for US graduate and undergraduate students in planetary science. The Planetary Geology Division of the Geological Society of America chose Maurel’s presentation from among 128 talks considered this year. She presented “Partial Differentiation and Magnetic History of the IIE Iron Meteorite Parent Body.”

How planets form is an open question. The mechanisms and timing of dust and rock accretion that eventually created larger planetary bodies remain unclear. The planetary science community mostly relies on numerical models to study how planets form, and experimental constraints are rare but nonetheless essential. To address the question of planet formation, researchers study the structure of ancient protoplanets, today destroyed or accreted into one of the solar system’s planets, based on the clues left in the compositions and physical properties of their remnant pieces: the meteorites.

The research community are debating the structure of protoplanets. Based on meteorites compositions, it is traditionally proposed that some protoplanets remained with their primitive composition (i.e., were never heated above melting temperature), and some others were heated internally and melted throughout their entire interior, yielding differentiation into a core and a mantle—like the Earth. Another point of view is that these are two extreme cases, and that most of the protoplanets were melted partially, preserving part of their primitive material in an outer silicate layer, melting the rest and forming a core overlain by a melted silicate mantle. To support the latter hypothesis, researchers would need to identify a group of meteorite that preserved the record of such a partially-differentiated structure.

The group of iron meteorites that Maurel studied (the IIE irons) was an interesting candidate. Previous studies had shown that these meteorites contain pieces of melted and unmelted silicates, suggesting partial melting. In this work, Maurel and her colleagues found magnetic evidence of the existence of a core in the parent protoplanet—the last piece of the puzzle needed to “build” a partially-differentiated object containing a metallic core, melted silicate mantle and unmelted crust. This result completes an important body of evidence that partial differentiation occurred among protoplanets. In turn, it favors a gradual accretion, possibly starting with the early and fast creation of embryos that had enough energy to melt, followed by a million-year long period of accretion of cold material forming unmelted silicate layers.

Maurel will receive her award plaque at the 51st annual Lunar and Planetary Science Conference in 2020.

The awards were endowed by Dr. Stephen E. Dwornik, who wanted to encourage US students to become involved with NASA and planetary science. They consist of a plaque and a monetary award.

Story Image: Clara Maurel with colleagues at the 50th Lunar and Planetary Science Conference (Credit: courtesy of Clara Maurel)