A Hope College professor's on-going study of neutron stars with NASA has received support through a Cottrell College Science Award from Research Corporation.
Dr. Peter Gonthier, associate professor of
physics, is studying how neutron stars produce gamma
radiation, seeking to find a model that explains why the
stars behave as they do. It's highly theoretical research,
but also the sort of how-the-universe-works question that
Gonthier finds compelling.
"NASA has a vested interest in high-energy
phenomena, and this is just one class of objects that
exhibits this set of characteristics that we somehow need to
explain in order to understand the universe we live in," he
said. "The challenge is to develop the theory that applies
to these environments."
Gonthier noted that neutron stars have about one-
and-a-half times the mass of earth's sun, while being
typically only 12 miles in diameter. He is part of a
research team studying a class of neutron star known as
pulsars, which emit a beam of gamma radiation that comes
into view from earth as the star rotates, much as a
lighthouse beam comes into and out of view.
By clocking the amount of time that passes between
the beam's appearances, scientists can measure how quickly
any given star is spinning. Pulsars might complete a
rotation as seldom as once every five seconds, or as often
as 1,000 times per second.
Scientists have learned that the stars slow down
as time passes, as they draw the energy for their beams from
their spinning energy, according to Gonthier.
Gonthier's work focuses on the role of the stars'
magnetic fields in the process. Since these strong field
environments cannot be reproduced on earth, researchers have
to rely on theory to describe phenomena near the surface of
He is focusing on a recently discovered type of
pulsar known as a magnetar. Magnetars have magnetic fields
that are 100 to 400 times stronger than is typical for
pulsars. "We're discussing perhaps the most intense
magnetic fields in the universe," he said.
Gonthier is conducting his research in
collaboration with Dr. Alice K. Harding at NASA's Goddard
Space Flight Center near Washington, D.C. He and Harding
have worked together since 1992, and he has been pursuing
his current research project since 1997. He anticipates
that their current project will require at least another
His activities this summer include working with
Harding and her team at the center for seven weeks. He is
accompanied by two student researchers: Michelle Ouellette,
a 1999 Hope graduate from Milford, and Rachel Costello, a
junior at the College of Wooster who is from Greensburg, Pa.
Research Corporation is a foundation for the
advancement of science. The Cottrell College Science
Program supports basic research in chemistry, physics and
astronomy at public and private, predominantly undergraduate
colleges. The $30,347 award that Gonthier received is
underwriting travel expenses and summer research stipends.
Support for the students' participation this
summer has also come from the Michigan Space Grant
Consortium, of which Hope is a member, and the National
Science Foundation's "Research Experiences for
Undergraduates" program. Through the funding from the
consortium, Ouellette is modelling the observability of the
gamma ray pulsars. Her research relates to NASA's work on a
gamma ray detector telescope that Gonthier said should be in
use in about five years.