Meteorite Analyses Provide Information on Timing of Solar System Formation
Andy Kerekgyarto, a Ph.D. student in the University of Houston’s Department of Earth and Atmospheric Sciences, was awarded a $30,000 per year graduate fellowship through NASA’s Earth and Space Science Fellowship program.
The fellowship, renewable for two additional years, supports his analysis of materials within one of the largest chondrite meteorites ever found on Earth. Kerekgyarto’s advisor is Tom Lapen, UH associate professor of geology.
“I’m focusing on calcium-aluminum-rich inclusions encased within the body of the Allende meteorite,” Kerekgyarto said. “These are believed to be some of the first materials to condense in our early solar system.”
The Allende meteorite fell to Earth in 1969 landing in northwestern Mexico. Because of its large size, samples were collected by numerous organizations. Kerekgyarto is studying samples on loan from the Houston Museum of Natural Science.
By using methods to analyze the age of the inclusions, Kerekgyarto can get an idea of the when the solar system started to form. One of the isotope systems he will utilize is Al-Mg, which is based on the decay of aluminum-26 to magnesium-26.
“Aluminum-26 has a short half-life of 700,000 years, so radioactive aluminum-26 inherited during solar system formation has been ‘extinct’ for billions of years at this point,” he said. “When magnesium-26 abundances are high relative to other isotopes of magnesium, it can be interpreted as the decay of aluminum-26.”
Because there is no live parent radioactive isotope left, Kerekgyarto is measuring the abundance of magnesium-26 relative to stable aluminum-27.
“The theory is that a supernova, which is a stellar explosion, injected the radioactive aluminum into the dust and gas triggering the gravitational collapse that led to the solar system formation,” Kerekgyarto said. “The radioactive aluminum also served as a heat source, aiding in planetary formation.”
Kerekgyarto makes the measurements using a minimally-destructive technique, Laser Ablation – Multicollector Inductively Coupled Plasma Mass Spectrometry.
Allende meteorite samples“The laser shoots tiny pits no more than 50 microns wide into the sample,” Kerekgyarto said. “This technique keeps the sample intact as opposed to older methods that involved crushing the sample and separating the minerals.”
These data will allow Kerekgyarto to test models of aluminum-26 injection into the collapsing solar nebula and to understand the timing and nature of processes that produced some of the first solar system solids.
Kerekgyarto has been doing this type of research for three years. “When I started my graduate studies, this research was a great way to combine two of my passions – geology and astronomy,” he said.
In addition to his advisor Lapen, Kerekgyarto is also working on this project with C. Ryan Jeffcoat and Dr. Minako Righter of UH, Dr. Rasmus Andreasen of Aarhus University, and Drs. Justin Simon and D. Kent Ross of NASA Johnson Space Center.
His project is one of only 29 planetary science research applications funded. NASA received 150 applications.
- Kathy Major, College of Natural Sciences and Mathematics