MSU faculty’s astronomy research shines on NEOWISE comet

by Sam Kealhofer, Intern on the A&S Research Support Team

The brightest comet in the northern hemisphere since 1997 reached naked eye visibility in July, quickly becoming a focus of research for Donna M. Pierce, an MSU physics and astronomy associate professor. Pierce captured pictures of Comet C/2020 (NEOWISE) from MSU’s Thad Cochran Research Park during the early morning hours of July 11, 2020. The comet was discovered in March but was not visible to the human eye until July.

Pierce studies the physical and chemical properties of comets to better understand the processes involved in the formation of new planets and solar systems.

Comets are small celestial bodies sometimes seen streaking across the sky. Their signature tails and “coma,” the atmosphere formed around the solid comet nucleus—the heart of the comet—are created when comets pass by the sun, warm and begin to release gasses. Comet Hale-Bopp in 1997 was the brightest comet prior to NEOWISE.

Pierce is currently researching how the ions in the atmosphere of comets emit their characteristic radiation signatures. In collaboration with Dennis Bodewits, associate professor of physics at Auburn University, and Ryan Fortenberry, assistant professor of chemistry and biochemistry from the University of Mississippi, the research is funded by an SEC Faculty Travel Grant.

Pierce believes the combination of laboratory astrophysics, emissions spectroscopy and theoretical astrochemistry will help fill critical data gaps because the team will be able to locate and interpret radiation signatures more reliably. They plan to build a database of comet ion information that will be useful to other astronomers and physicists who study various properties of molecules.

Pierce’s forthcoming article, “Examination of Fragment Species in the Comae of Several Comets Using an Integral Field Unit Spectrograph,” builds on her work from her 2014 NASA Planetary Atmospheres grant by recording crucial information about each comet’s physical and chemical makeup.

The results indicate comets fall into several established comet chemical families. One comet in particular, comet Hergenrother, is extremely depleted in many chemicals common to most comets. The number of known comets exhibiting this chemical depletion is extremely small and researchers are seeking to understand why some comets exhibit these properties.

Pierce’s 2017 article, “Jet Morphology and Coma Analysis of Comet 103P/Hartley 2,” published in “The Astronomical Journal,” highlights research on the Hartley 2 comet, which analyzes the spectral data for the coma of Harley 2 acquired from four nights of observation in late 2010.

Pierce and her graduate students enhanced and studied 150 images of the comet to reveal subtle coma structure, which allowed them to confirm that the nucleus of the comet rotates in an unusually complex manner. Furthermore, using various statistical techniques, they also established that the chemicals, whose signatures were observed in the coma, come from molecules released from the smaller, more highly active side of the comet’s nucleus.

Pierce’s research is highlighted each time a comet streaks across the sky, turning these events into opportunities to learn about our planet and solar system.

In an effort to contribute solutions to the various challenges facing the nation, as well as insight into other points of interest, the College of Arts & Sciences will continue to highlight faculty research in our “Research in the Headlines” series each Monday and Wednesday. For more research in the headlines, visit https://www.cas.msstate.edu/research/researchintheheadlines/; and for information about the College of Arts & Sciences or the Department of Physics and Astronomy visit https://www.cas.msstate.edu/ or https://www.physics.msstate.edu/.