High schoolers' discovery of millisecond pulsar may help astronomers detect elusive gravitational waves
The teen-agers are at it again.
And that’s a good thing, as five high school students working with the Pulsar Search Collaboratory – a joint project of West Virginia University and the National Radio Astronomy Observatory in Green Bank – have discovered a new star that spins as fast as a Formula 1 race car’s engine. This discovery may someday help astronomers detect ripples in spacetime known as gravitational waves.
The special star, called a millisecond pulsar, was discovered independently on Jan. 17 by Jessica Pal of Rowan County High School in Kentucky and Emily Phan of George C. Marshall High School in Virginia. It was then confirmed by Max Sterling of Langley High School and Sydney Dydiw of Trinity High School, both in Virginia, and Anne Agee of Fort Hill High School in Maryland.
As part of the Collaboratory, students analyze real data from NRAO’s Robert C. Byrd Green Bank Telescope to find pulsars. Their teachers introduced the PSC to their classes and interested students formed teams to continue the work.
“When you discover a pulsar, you feel like you’re walking on air!” Pal said. “It is the best experience you can ever have. You feel awesome and you become ‘famous.’ You get to meet astronomers and talk to them about your experience. I still can’t believe I found a pulsar. It is wonderful to know that there is something out there in space that you discovered.”
Once the pulsar candidate was reported to NRAO, a follow-up observing session was scheduled and observations on Jan. 24 showed that the signals were astronomical in nature and the pulsar was confirmed.
Pulsars are spinning neutron stars that sling “lighthouse beams” of radio waves around as they spin. A neutron star is what is left after a massive star explodes at the end of its “normal” life. With no nuclear fuel left to produce energy to offset the stellar remnant’s weight, its material is compressed to extreme densities. The pressure squeezes together most of its protons and electrons to form neutrons; hence, the name “neutron star.” One tablespoon of material from a pulsar would weigh 10 million tons.
The object that the students discovered is in a special class of pulsar that spins very fast – in this case, about 324 times per second. Millisecond pulsars, the fastest-spinning pulsars, are highly stable and keep time more accurately than atomic clocks.
There are still many things that we do not understand about these stars, however.
“Despite having known about millisecond pulsars for almost thirty years, they are so difficult to find that our knowledge of these objects is still in its infancy,” said Duncan Lorimer, WVU’s Woodburn Professor of Physics.
One thing we do know, however, is that because of their stability, these pulsars may someday allow astronomers to detect gravitational waves.
“Gravitational waves are ripples in the fabric of spacetime predicted by Einstein’s theory of General Relativity,” says Maura McLaughlin, associate professor of physics, “We have very good proof for their existence but, despite Einstein’s prediction back in the early 1900s, they have never been detected.”
Millisecond pulsars, however, could hold the key to that discovery. Like buoys bobbing on the ocean, the light travel times between pulsars can be perturbed by gravitational waves.
“Gravitational waves are invisible,” says McLaughlin. “But by timing pulsars distributed across the sky, we may be able to detect very small changes in pulse arrival times due to the influence of these waves.”
Millisecond pulsars are generally older pulsars that have been “spun up” by stealing mass from companion stars, but much is left to discover about their formation.
“This latest discovery will help us understand the genesis of millisecond pulsars. It’s a very exciting time to be finding pulsars!” Lorimer said.
The PSC, a joint project of NRAO and WVU, is funded by a grant from the National Science Foundation. The PSC includes training for teachers and student leaders, and provides parcels of data from the GBT to student teams. The project involves teachers and students in helping astronomers analyze data from the GBT, a giant, 17-million-pound telescope.
Approximately 300 hours of the observing data were reserved for analysis by student teams. These students have been working with about 500 other students across the country. The responsibility for the work, and for the discoveries, is theirs. They are trained by astronomers and by their teachers to distinguish between pulsars and noise.
In addition to this discovery, five other astronomical objects, including four pulsars, have been discovered by students. This is the first millisecond pulsar.
Those involved in the PSC hope that being a part of astronomy will give students a greater awareness of and appreciation for scientific research.
It already has for Agee, who says she is considering astronomy as a career. “The Pulsar Search Collaboratory has opened my eyes to how fun astronomy can be!” she said.
The PSC will continue through the 2012-2013 school year. Teachers interested in participating in the program can learn more at http://www.gb.nrao.edu/epo/psc.shtml. The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.
CONTACT: Rebecca Herod, Eberly College of Arts and Sciences
304.293.7405, ext. 5251; Rebecca.Herod@mail.wvu.edu.
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