NAU planetary astronomer receives NASA grants for two new studies of Main Asteroid Belt

Cristina Thomas

The majority of asteroids in the solar system are found in the Main Asteroid Belt, which is located between the orbits of Mars and Jupiter. Although millions of objects populate the belt, most are relatively small, and astronomers have not studied many of them in detail.

NAU assistant professor Cristina Thomas, whose research focuses on asteroids, recently received two grants from NASA to study two different types of asteroids in the Main Asteroid Belt. The results of her studies will add to the existing body of knowledge in this field, helping scientists better understand the origins of asteroids.

$100,000 grant to study ‘space weathering’ of small Koronis asteroids

Thomas, who was selected as a NASA Early Career Fellow in 2014, recently received $100,000 in funding through the fellowship program for a pilot study of small asteroids in the Koronis family, a large family of stony asteroids thought to have been formed at least two billion years ago in a catastrophic collision between two precursor asteroids. Thomas will obtain observations of small Koronis family members using the NASA Infrared Telescope Facility (IRTF) to determine whether they have the same spectral characteristics as the largest family members.

“Past capabilities have limited our spectral observations to the largest objects in the Main Belt, so this is something that very few have done,” she said. “Specifically, I’m looking for signs of space weathering, which is the result of an object being exposed to the space environment over time. Space weathering is a long-standing question in asteroid science that affects spectroscopic interpretations of near-Earth and Main Belt asteroids.”

“We haven’t done a lot of work on small objects in the Main Belt, but I have done some work on the Koronis family in the past, so it seemed like a good place to start. I’m excited it’s been selected!”

In a previous study of the Koronis family of asteroids, Thomas examined changes in spectral slope within the family that are indicative of space weathering. Her findings implied that unweathered objects exist in the family.

$331,000 grant to understand Trojan-like asteroids

Thomas also was recently awarded a $331,000 grant by NASA for a three-year project to find asteroids with spectra similar to the Jupiter Trojans in the Main Asteroid Belt. Graduate student Oriel Humes is working on the project with Thomas.

“The Trojan asteroids have very specific spectral slopes in visible and near-infrared wavelengths,” Thomas said. “I used results from the Sloan Digital Sky Survey, which observed a lot of objects but has very limited data, to identify these Trojan-like candidates in the Main Belt. The work will tell us about the delivery of material to the Main Belt from the outer solar system when the planets were migrating and the Trojan population was captured in their orbits near Jupiter.”