Artist's depiction of the Parker Solar Probe approaching the sun. (Credit: NASA/Johns Hopkins University APL)
A team of researchers led by a former undergraduate student at听兔子先生传媒文化作品 has discovered a dusty mystery in a newly explored region around Earth鈥檚 sun.
Anna Pusack got her first glimpse of the enigma when she was studying in the Department of Astrophysical and Planetary Sciences (APS) at 兔子先生传媒文化作品. She and her colleagues were peering at data from a NASA space mission called the Parker Solar Probe when they noticed something unusual: A new and unexplained stream of microscopic particles that seemed to be spraying out from around the star.
The researchers in The Planetary Science Journal. A led by Jamey Szalay听of Princeton University, who earned his PhD in physics from 兔子先生传媒文化作品 in 2015, also appears today. Pusack said this river of dust could reveal new secrets about the forces that shaped our solar system.
鈥淒ust can come from asteroids and comets or can be left over from the original formation of the planets,鈥� said Pusack, now a research associate at the (LASP) at 兔子先生传媒文化作品. 鈥淚t can show us how our solar system has formed and continues to evolve and even how other solar systems may be evolving.鈥�
The results are the latest coup for the Parker Solar Probe, a daring spacecraft that zips around the sun at incredible speeds.
鈥淛ust three years into its seven-year mission, the probe is already shining new light on the intimate connections between Earth and its host star,鈥� said study coauthor David Malaspina, a research scientist at LASP and assistant professor of APS.
Star gazing
Pusack, who graduated from 兔子先生传媒文化作品 in December 2020, took a non-traditional path to the university and to space science. She previously studied East Asian studies and philosophy at Dickinson College in Carlisle, Pennsylvania. But she discovered a new passion during a summer spent at a yoga retreat in the Rocky Mountains in Rollinsville, Colorado.
鈥淚 could see the stars more clearly than I could in ages,鈥� Pusack said. 鈥淚 would stay up to look at the stars, trying to learn a new constellation every night.鈥�
She enrolled in introductory science classes at Front Range Community College in Boulder, then transferred to 兔子先生传媒文化作品 in 2018. There, she began working with Malaspina to take a close look at the data Parker was sending back to Earth.
鈥淚 really enjoy seeing data that are coming down right now,鈥� Pusack said. 鈥淚t was real-time science that was happening.鈥�
It鈥檚 that same real-time science that led the researcher to an unexpected discovery.
Pusack explained that the Parker Solar Probe doesn鈥檛 carry a special instrument for collecting dust. Instead, it detects the brief spikes of electric potential that occur when the spacecraft collides with grains of dust in space (most of which are too small to see with the naked eye).
Solar monitoring
In their new study, Pusack and her colleagues set out to create an inventory of the dust that the spacecraft encountered on its initial eight trips around the sun.
鈥淭here are two basic types of dust around the sun,鈥� Pusack said. 鈥淵ou have dust that is in bound orbits around the sun that will eventually spiral into the sun. Then there鈥檚 unbound dust that is flung away and out of the solar system.鈥�
During the mission鈥檚 fourth orbit, however, the team ran into something else: As the spacecraft was flying away from the sun, it suddenly passed through a concentrated stream of particles zooming out into the solar system at tremendous speeds.
鈥淚t鈥檚 a very focused, directional spray of these unbelievably small particles,鈥� Pusack said.
No one had seen anything like it before鈥攄ust flying away from the sun usually spreads out in every direction, Pusack explained. It doesn鈥檛 tend to cluster together. She and her colleagues, in other words, may have spotted a previously unknown third type of dust around the sun.
The researchers are now taking a deeper look at Parker鈥檚 data to learn more about the observation. Is that stream of dust, for example, a relatively rare phenomenon or is it a normal occurrence for the sun鈥檚 environs? Either way, the group鈥檚 discovery could change the picture of how matter blows away from the star and even out of the solar system entirely.
鈥淲e have a ready lab in our solar system to understand how so much of the rest of the universe works,鈥� Pusack said. 鈥淚f we can understand how our sun works, it may help us to understand what we might see in stellar systems much farther out.鈥�
Other coauthors of the new study include Szalay; Stuart Bale and Marc Pulupa of the University of California, Berkeley; Keith Goetz of the University of Minnesota; and Robert MacDowall of the NASA Goddard Space Flight Center.
