posted June 22, 1999

Project Studies Neutron Stars

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
  neutron stars.
          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.