When
3:45 p.m., April 7, 2015
Where
Kuiper Space Sciences 312
Dr. Steven Desch
Associate Professor
Arizona State University
Chondrule Formation in Bow Shocks around Planetary Embryos
To understand how planets and planetary systems form, no better dataset exists than meteorites, which are physical samples present when our own solar system formed. But deciphering what they have to say is a complex and difficult process of developing and testing of many models. In my talk I will discuss this process in the context of chondrules, which are millimeter-sized igneous inclusions in chondrites. Each was melted in the solar nebula, and the mechanism by which this happened has been a long-standing mystery. I will discuss the reasons why passage through shock waves in the solar nebula gas appears to be the only viable mechanism. I will then discuss our recently published results on melting of chondrules in the shock waves surrounding planetary embryos (radius > 1000 km) on eccentric orbits. This new model appears consistent with all known aspects of chondrules, including the exceptionally high inferred partial pressures of Na and H2O in the chondrule-forming region. This new model does strongly imply that chondrules are not the building blocks of planets we used to think they were, but rather a curious side effect at the tail end of planet formation.
Associate Professor
Arizona State University
Chondrule Formation in Bow Shocks around Planetary Embryos
To understand how planets and planetary systems form, no better dataset exists than meteorites, which are physical samples present when our own solar system formed. But deciphering what they have to say is a complex and difficult process of developing and testing of many models. In my talk I will discuss this process in the context of chondrules, which are millimeter-sized igneous inclusions in chondrites. Each was melted in the solar nebula, and the mechanism by which this happened has been a long-standing mystery. I will discuss the reasons why passage through shock waves in the solar nebula gas appears to be the only viable mechanism. I will then discuss our recently published results on melting of chondrules in the shock waves surrounding planetary embryos (radius > 1000 km) on eccentric orbits. This new model appears consistent with all known aspects of chondrules, including the exceptionally high inferred partial pressures of Na and H2O in the chondrule-forming region. This new model does strongly imply that chondrules are not the building blocks of planets we used to think they were, but rather a curious side effect at the tail end of planet formation.
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