View my Thesis: Can porphyritic chondrules form in planetary embryo bow shocks?
The story
Chondrules are mm-sized igneous inclusions found in the most primitive meteorites, called chondrites. Chondrules provide us with snapshots of the solar nebula and are the key to understanding the history of the Solar System as well as the formation of terrestrial planets such as that of Earth. Chondrules formed in the first few million years of the Solar System’s history (Kita & Ushikubo, 2012), during its protoplanetary disk phase, and so understanding the energetic event(s) that melted chondrules is key to using meteoritic data to constrain the astrophysical models of the disk.
What came first, the chicken or the egg?
The community has yet to settle on a chondrule formation mechanism, but nebular shocks are currently the most favored. The planetary embryo bow shock model is very attractive as it not only meets the thermal constraints required to form chondrules, but it has a paradigm shift associated with it: rather than chondrules being the presumed building blocks of planets, they would have to be a by-product of planet formation indicating that planetary embryos were already in existence prior to chondrules.
What I did
My research involved conducting dynamic crystallization experiments using a 1 atmosphere vertical gas-mixing furnace at the Experimental Petrology & Igneous processes Center (EPIC) led by PI, Christy Till, to address whether or not porphyritic chondrules (the most dominant type of chondrule) can form in planetary embryo bow shocks by reproducing chondritic textures using natural chondrule analogs. 133 experiments to be exact!
As part of my Master's thesis work, I explored a wide variety of parameters such as grain size, peak temperatures, heating durations, and cooling rates to test the validity of the planetary embryo bow shock model. I subsequently analyze the resulting textures using the JXA-8530F Electron Probe Microanalyzer (EPMA) located in the John M. Cowley Center for High Resolution Electron Microscopy at Arizona State University.
For more details, please review some of my abstracts linked below. My first publication is currently in revision.
The story
Chondrules are mm-sized igneous inclusions found in the most primitive meteorites, called chondrites. Chondrules provide us with snapshots of the solar nebula and are the key to understanding the history of the Solar System as well as the formation of terrestrial planets such as that of Earth. Chondrules formed in the first few million years of the Solar System’s history (Kita & Ushikubo, 2012), during its protoplanetary disk phase, and so understanding the energetic event(s) that melted chondrules is key to using meteoritic data to constrain the astrophysical models of the disk.
What came first, the chicken or the egg?
The community has yet to settle on a chondrule formation mechanism, but nebular shocks are currently the most favored. The planetary embryo bow shock model is very attractive as it not only meets the thermal constraints required to form chondrules, but it has a paradigm shift associated with it: rather than chondrules being the presumed building blocks of planets, they would have to be a by-product of planet formation indicating that planetary embryos were already in existence prior to chondrules.
What I did
My research involved conducting dynamic crystallization experiments using a 1 atmosphere vertical gas-mixing furnace at the Experimental Petrology & Igneous processes Center (EPIC) led by PI, Christy Till, to address whether or not porphyritic chondrules (the most dominant type of chondrule) can form in planetary embryo bow shocks by reproducing chondritic textures using natural chondrule analogs. 133 experiments to be exact!
As part of my Master's thesis work, I explored a wide variety of parameters such as grain size, peak temperatures, heating durations, and cooling rates to test the validity of the planetary embryo bow shock model. I subsequently analyze the resulting textures using the JXA-8530F Electron Probe Microanalyzer (EPMA) located in the John M. Cowley Center for High Resolution Electron Microscopy at Arizona State University.
For more details, please review some of my abstracts linked below. My first publication is currently in revision.
CONFERENCE PRESENTATIONS
Perez, A. M., Desch, S. J., Schrader, D. L., & Till, C.B. An Experimental Investigation of the Planetary Embryo Bow Shock Model as a Chondrule Formation Mechanism [2041]. 49th Lunar and Planetary Science Conference, Houston, TX, March 2018. (oral presentation)
View abstract
Perez, A. M., Desch, S. J., Schrader, D. L., & Till, C.B. Understanding the conditions of planet formation through chondrules [4084]. Habitable Worlds 2017, Laramie, WY, November 2017. (poster presentation)
View abstract
View e-poster
Perez, A. M., Desch, S. J., Schrader, D. L., & Till, C.B. Determining the relative timing of formation of chondrules vs planetary embryos through experiments. [2037]. The First Billion Years: Accretion, Houston, TX, August 2017. (oral presentation)
View abstract
Perez, A. M., Desch, S. J., Schrader, D. L., & Till, C.B. Can porphyritic chondrules form in planetary embryo bow shocks? [2014]. Chondrules as Astrophysical Objects, Vancouver, BC, Canada, May 2017. (oral presentation and session chair)
View abstract
Perez, A. M., Desch, S. J., Schrader, D. L., & Till, C.B. An Experimental Investigation of the Planetary Embryo Bow Shock Model as a Chondrule Formation Mechanism [2041]. 49th Lunar and Planetary Science Conference, Houston, TX, March 2018. (oral presentation)
View abstract
Perez, A. M., Desch, S. J., Schrader, D. L., & Till, C.B. Understanding the conditions of planet formation through chondrules [4084]. Habitable Worlds 2017, Laramie, WY, November 2017. (poster presentation)
View abstract
View e-poster
Perez, A. M., Desch, S. J., Schrader, D. L., & Till, C.B. Determining the relative timing of formation of chondrules vs planetary embryos through experiments. [2037]. The First Billion Years: Accretion, Houston, TX, August 2017. (oral presentation)
View abstract
Perez, A. M., Desch, S. J., Schrader, D. L., & Till, C.B. Can porphyritic chondrules form in planetary embryo bow shocks? [2014]. Chondrules as Astrophysical Objects, Vancouver, BC, Canada, May 2017. (oral presentation and session chair)
View abstract
Acknowledgments
We would like to thank: the Smithsonian Institution, the members of the Meteorite Working Group, Cecilia Satterwhite and Kevin Righter (NASA, Johnson Space Center) for the sample of QUE 97008 that was used in this work. US Antarctic meteorite samples are recovered by the Antarctic Search for Meteorites (ANSMET) program, which has been funded by NSF and NASA, and characterized and curated by the Department of Mineral Sciences of the Smithsonian Institution and Astromaterials Curation Office at NASA Johnson Space Center. We are grateful to Axel Wittmann for assistance with EPMA at ASU and Sam Dunaway, owner of Morefield Gem Mine in Amelia County, Virginia for providing the albite for this work. This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
FUN FACT: The song, Wasp, by Motionless in White was played while the sample was placed inside the furnace during every experimental run. Due to this song being played 133 times for the sake of chondrule making, I decided to "retire" it and no longer listen to it.