French Leads NSF-Funded Study of Asteroids
Chair and Professor of Physics Linda French
Sept. 7, 2012
BLOOMINGTON, Ill. – Adding to the body of knowledge regarding the formation and evolution
of our solar system will be the focus of a National Science Foundation (NSF)-funded
study led by Illinois Wesleyan University Chair and Professor of Physics Linda M.
French and involving astronomers from Georgia State University, Lowell Observatory
in Arizona, and the Center for Solar System Studies in California.
The three-year award, totaling $256,451, is entitled "RUI: Photometric Survey of Jovian
Trojans." The project involves a systematic study of Trojan asteroids, a large group
of more than 5,000 objects sharing Jupiter's orbit around the sun. "RUI" is an acronym
for "Research at Undergraduate Institutions," NSF's RUI activity supports research
at predominantly undergraduate institutions.The grant will allow two Illinois Wesleyan
students and a Georgia State University graduate student to travel to observatories
in Arizona and Chile, plan observations and learn observing techniques, and present
their findings in national conferences and in peer-reviewed journals. As principal
investigator, French estimates it will take her two months each summer to complete
French and her colleagues in the physics department have long been committed to involving
undergraduate students in research. "Being on site, planning and carrying out observations,
and then reducing and analyzing data, are totally different experiences to sitting
in the classroom," she said. "Students learn how the doing of science really works. This can be both extremely exciting and intensely frustrating."
In astronomy, a Trojan is a minor planet or moon that shares an orbit with a planet
or larger moon. "Trojans, in general, look a lot like the bare nuclei of comets when
the comets are too far away from the sun to have a tail," explained French. "Comets
live much further out in the solar system than planets and normal asteroids." One
model involving the Jovian Trojans suggests that in the early days of the solar system,
a barrage of comets impacted the inner solar system. "At least some of the Jovian
Trojans might be relics of those comets, and some might have formed closer to where
they are today," she said. A systematic study of the compositional classes of Trojans,
therefore, can help determine whether or not all Trojans originated in the same place,
The Jovian Trojans, due to their location at Jupiter's two stable Lagrange points,
may provide clues about the history and evolution of the solar system, French explained.
Lagrangian points lie 60 degrees ahead of and behind the planet in its orbit.
During the three-year photometric study, researchers will obtain 1) a complete set
of broadband 4-color (BVRI) for 150 objects that can be used to distinguish the two
main spectral classes of objects found among the Trojans; and 2) a bias-corrected
set of rotation data for up to 100 objects. "We will search for trends in rotation
period with size and compositional class, and compare our results with those for objects
that could be related, such as main-belt asteroids and large outer-belt asteroids,"
"Considerable research has been conducted on individual Trojans, but through our project,
we'd like to be able to say whether small Trojans rotate faster or slower than big
ones, and whether asteroids of a certain color (which indicates composition) rotate
faster or slower than ones of a different color," French added.
She added that the name "Trojans" as applied to these heavenly bodies was derived
by accident. "The first one discovered was named Achilles, after the Greek hero of
the Trojan War," French explained. "The second was named after his comrade Patroclus,
and the third after the Trojan hero Hektor. The group of asteroids preceding Jupiter
is named after Greeks, and the group that follows is named after Trojans. By now,
however, thousands have been discovered, way too many to find names in the Iliad and the Aeneid."
Contact: Kim Hill, (309) 556-3960