Arecibo REU Student Publishes AO Radar Study on Large Potentially Hazardous Asteroid

Physical model of asteroid Midas’ shape and a map of the gravitational slopes across its surface produced for the publication in the Planetary Science Journal.

Riley McGlasson, a 2018 Research Experience for Undergraduates (REU) summer student at the Arecibo Observatory, published a detailed study of the asteroid 1981 Midas in the Planetary Science Journal. The analysis combined radar data from the Arecibo Observatory and NASA’s Goldstone Deep Space Communications Complex with optical data from telescopes across the world to provide a comprehensive mathematical description of the asteroid’s shape, its spin rate, its orientation in space, and the gravitational slopes across its surface.

With a maximum length measuring 3.4 km (2.1 miles), asteroid Midas is one of the largest objects known as a Potentially Hazardous Asteroid, meaning its closest approaches to Earth come within 19 times the Earth-Moon distance.

While this asteroid poses no risk of impact with the Earth for at least nine centuries, “its large size and its occasional close proximity to Earth make Midas a high-priority object to study,” says Ms. McGlasson, who was a physics major at Macalester College in Minnesota at the time of her summer internship.

The computational modeling of the asteroid was made more complex by its distinctive, peanut-like shape. Asteroids with shapes like this are known as contact binaries because the two lobes may have once been separate asteroids.

“Creating a model of Midas’ shape and structure is critical for understanding the dynamical environment around contact binaries, and enables orbital dynamical studies that could be used to assist small-bodies mission planning,” explains Ms. McGlasson.

Dr. Sean Marshall, the Arecibo scientist who mentored Ms. McGlasson during her internship and a co-author of the study, adds, “Asteroid Midas is definitely not just a simple sphere, so it's nice to have a detailed physical model. Every asteroid is a little different, and this adds to our understanding of the population.”

Ms. McGlasson’s work was not only important for the planetary science community, but also for her discovering her own passion for planetary science research.

“My Arecibo REU experience singlehandedly guided my decision to pursue a career in planetary science,” says Ms. McGlasson. “The AO REU introduced me to the power of planetary radar, which I used to create the asteroid model, and also will be the focus of my PhD dissertation.”

Following her graduation from Macalester College, Ms. McGlasson joined the doctoral program at Purdue University, working with another former Arecibo REU student, Dr. Ali Bramson. Ms. McGlasson’s current research includes the analysis of data from the Mars Reconnaissance Orbiter, which uses radar to peer into Mars’ ice, so she can learn about the planet’s past climate.

“The Arecibo Observatory's REU program has made a huge difference in the careers of many former students,” says Dr. Marshall. “Ms. McGlasson did a great job with a challenging project, and I look forward to seeing what she will accomplish over the course of her career.”

While the 305 meter dish is no longer operational, Dr. Marshall adds, “We still have lots of archived data waiting to be analyzed in more detail. Some of those data are well suited for student projects like this one.”

The REU program is funded by the National Science Foundation to support active research participation by undergraduate students. The Arecibo Observatory was one of the first astronomy REU sites, and has been hosting the program since 1987, though AO has operated undergraduate internship programs since 1972. The Arecibo REU program was recently awarded funding for continuation through 2024.^[a]

Other co-authors on this publication include AO’s Flaviane Venditti and Anne Virkki; as well as Shantanu Naidu, Lance Benner, Marina Brozović, Jon Giorgini, and James Young from NASA’s Jet Propulsion Laboratory; Patrick Taylor and Betzaida Aponte from the Lunar and Planetary Institute; Alan Harris from MoreData! Inc.; Marek Husárik from the Astronomical Institute of the Slovak Academy of Sciences; and Guy Wells, Daniel Bamberger, and Jeff Tobak from the Northolt Branch Observatories.

Riley McGlasson was supported by the Arecibo Observatory Research Experience for Undergraduates program, National Science Foundation grant 1559849. This research also was supported by NASA's Near-Earth Object Observations Program through grants NNX13AQ46G, 80NSSC18K1098, and 80NSSC19K0523.