Stellar discovery excites students

Feb 03, 2011 By Sue Ann Heatherly
Basics of a Pulsar. Credit: Bill Saxton, NRAO/AUI/NSF

In the constellation of Ophiuchus, above the disk of our Milky Way Galaxy, there lurks a stellar corpse spinning 30 times per second -- an exotic star known as a radio pulsar. This object was unknown until it was discovered last week by three high school students. These students are part of the Pulsar Search Collaboratory (PSC) project, run by the National Radio Astronomy Observatory (NRAO) in Green Bank, WV, and West Virginia University (WVU).

The , which may be a rare kind of neutron star called a recycled pulsar, was discovered independently by Virginia students Alexander Snider and Casey Thompson, on January 20, and a day later by Kentucky student Hannah Mabry. "Every day, I told myself, 'I have to find a pulsar. I better find a pulsar before this class ends,'" said Mabry.

When she actually made the discovery, she could barely contain her excitement. "I started screaming and jumping up and down."

Thompson was similarly expressive. "After three years of searching, I hadn't found a single thing," he said, "but when I did, I threw my hands up in the air and said, 'Yes!'."

Snider said, "It actually feels really neat to be the first person to ever see something like that. It's an uplifting feeling."

As part of the PSC, the students analyze real data from NRAO's Robert C. Byrd Green Bank Telescope (GBT) to find pulsars. The students' teachers -- Debra Edwards of Sherando High School, Leah Lorton of James River High School, and Jennifer Carter of Rowan County Senior High School -- all introduced the PSC in their classes, and interested students formed teams to continue the work.

Even before the discovery, Mabry simply enjoyed the search. "It just feels like you're actually doing something," she said. "It's a good feeling."

Once the pulsar candidate was reported to NRAO, Project Director Rachel Rosen took a look and agreed with the young scientists. A followup observing session was scheduled on the GBT. Snider and Mabry traveled to West Virginia to assist in the follow-up observations, and Thompson joined online.

"Observing with the students is very exciting. It gives the students a chance to learn about radio telescopes and pulsar observing in a very hands-on way, and it is extra fun when we find a pulsar," said Rosen.

Snider, on the other hand, said, "I got very, very nervous. I expected when I went there that I would just be watching other people do things, and then I actually go to sit down at the controls. I definitely didn't want to mess something up."

Everything went well, and the observations confirmed that the students had found an exotic pulsar. "I learned more in the two hours in the control room than I would have in school the whole day," Mabry said.

Pulsars are spinning that sling lighthouse beams of radio waves or light 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 -- as much as a supertanker.

The object that the students discovered is in a special class of pulsar that spins very fast - in this case, about 30 times per second, comparable to the speed of a kitchen blender.

"The big question we need to answer first is whether this is a young pulsar or a recycled pulsar," said Maura McLaughlin, an astronomer at WVU. "A pulsar spinning that fast is very interesting as it could be newly born or it could be a very old, recycled pulsar."

A recycled pulsar is one that was once in a binary system. Material from the companion star is deposited onto the pulsar, causing it to speed up, or be recycled. Mystery remains, however, about whether this pulsar has ever had a companion star.

If it did, "it may be that this pulsar had a massive companion that exploded in a supernova, disrupting its orbit," McLaughlin said. Astronomers and students will work together in the coming months to find answers to these questions.

The PSC is a joint project of the and West Virginia University, funded by a grant from the National Science Foundation. The PSC, led by NRAO Education Officer Sue Ann Heatherly and Project Director Rachel Rosen, 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.

Some 300 hours of observing data were reserved for analysis by student teams. Thompson, Snider, and Mabry have been working with about 170 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. The students' collective judgment sifts the pulsars from the noise.

All three students had analyzed thousands of data plots before coming upon this one. Casey Thompson, who has been with the PSC for three years, has analyzed more than 30,000 plots.

"Sometimes I just stop and think about the fact that I'm looking at data from space," Thompson said. "It's really special to me."

In addition to this discovery, two other astronomical objects have been discovered by students. In 2009, Shay Bloxton of Summersville, WV, discovered a pulsar that spins once every four seconds, and Lucas Bolyard of Clarksburg, WV, discovered a rapidly rotating radio transient, which astronomers believe is a pulsar that emits radio waves in bursts.

Those involved in the PSC hope that being a part of astronomy will give students an appreciation for science. Maybe the project will even produce some of the next generation of astronomers. Snider, surely, has been inspired.

"The PSC changed my career path," confessed Thompson. "I'm going to study astrophysics."

Snider is pleased with the idea of contributing to scientific knowledge. "I hope that astronomers at Green Bank and around the world can learn something from the discovery," he said.

Mabry is simply awed. "We've actually been able to experience something," she said.

Explore further: Thermonuclear X-ray bursts on neutron stars set speed record

add to favorites email to friend print save as pdf

Related Stories

Astronomers discover fastest-spinning pulsar

Jan 12, 2006

A team of astronomers led by McGill University graduate student Jason Hessels has discovered the fastest-spinning neutron star, or pulsar, ever found. The 20-mile-diameter superdense pulsar, which at 716 revolutions ...

New technique improves estimates of pulsar ages

Jun 09, 2009

Astronomers at the University of California, Santa Cruz, have developed a new technique to determine the ages of millisecond pulsars, the fastest-spinning stars in the universe.

A Neutron Star Spins Toward Intergalactic Space

Feb 10, 2006

The Milky Way's fastest observed pulsar is speeding out of the galaxy at more than 670 miles a second, propelled largely by a kick it received at its birth 2.5 million years ago.

Recommended for you

How can we find tiny particles in exoplanet atmospheres?

11 hours ago

It may seem like magic, but astronomers have worked out a scheme that will allow them to detect and measure particles ten times smaller than the width of a human hair, even at many light-years distance.  ...

Spitzer telescope witnesses asteroid smashup

Aug 28, 2014

(Phys.org) —NASA's Spitzer Space Telescope has spotted an eruption of dust around a young star, possibly the result of a smashup between large asteroids. This type of collision can eventually lead to the ...

Witnessing the early growth of a giant

Aug 27, 2014

Astronomers have uncovered for the first time the earliest stages of a massive galaxy forming in the young Universe. The discovery was made possible through combining observations from the NASA/ESA Hubble ...

User comments : 17

Adjust slider to filter visible comments by rank

Display comments: newest first

Quantum_Conundrum
1 / 5 (15) Feb 03, 2011
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 -- as much as a supertanker.


Except when you do the math, this theory doesn't work, because the amount of energy needed to explode the star is more than any normal fusion process or electron capture process can make. Only an anti-matter annihilation can release enough energy to cause a supernova.

the neutron star is NOT a by-product of the explosion. The Neutron star's gravity causes the explosion by starting a chain reaction by colliding protons to make ANTI-neutrons, which then decay into anti-protons and positrons, which annihilate.
Quantum_Conundrum
1.3 / 5 (14) Feb 03, 2011
Normal fusion doesn't make enough power to do much more than burp the gases off the surface of a star, even if all the matter fused instantaneously.

When the core collapses, the remaining "ordinary matter" above it falls into the void and is smashed onto the surface of the neutron star as the remaining protos in the hydrogen and helium "outer layers" of the star collide with one another, making anti-neutrons. This causes a stellar mass anti-matter annihilation in a shell of collapsing matter immediately surrounding the neutron star, which in turn blows off the outer 1/3 to 1/2 of the star, leaving behind about 1/3 to 1/4 of the original mass as the Neutron star which started it all...

If you do not believe this, integrate the gravitational acceleration formula and plug in a stellar mass or two for the big "M", and neutron star radii for "r". No matter how much you try or lie, you cannot overcome that much gravitation through a fusion-based explosion.
TopherTO
5 / 5 (9) Feb 03, 2011
QC you found another issue with their math?

Everytime I read an article on PhysOrg you are ranting about numbers not adding up. I guess there is a massive conspiracy to spread cosmological lies...

Or we are in need of a global recall on faulty calculators.
omatumr
1.1 / 5 (8) Feb 03, 2011
Congratulations!

Keep looking! You may find proto-planetary debris orbiting that pulsar.

At least, that seems to be how planets formed here in the solar system ["Nuclear Systematics: Part IV. Neutron-capture cross sections and solar abundance", Journal of Radioanalytical and Nuclear Chemistry, vol. 266, No. 2 (2005) 159–163].

With kind regards,
Oliver K. Manuel
Nik_2213
3.5 / 5 (2) Feb 03, 2011
Uh, perhaps the collapse / accretion is not spherically symmetric ?? Stars do rotate and, IIRC, most stars rotate much faster than our Sun...
Kumelys
4.8 / 5 (8) Feb 03, 2011
QC your math is 'stellar' in some aspects. Fusion has so little to do with super novas... There are not only fusion caused repulsion and gravitation in star, there is also hydrostatic pressure, convection currents and many other interesting things going in there. I would advice you to read some serious books on subject (serious, I mean, let's say textbooks for astronomy undergraduates or something, start with Carroll 'Fundamental Astrophysics', great start) and brag that their math is wrong and only you are right after that.
technicalengeneering
4.5 / 5 (8) Feb 04, 2011
@ QC

ANTI-NEUTRONS.... Now where doesn't that add up?
omatumr
1 / 5 (7) Feb 04, 2011
No matter how much you try or lie, you cannot overcome that much gravitation through a fusion-based explosion.


Neutron repulsion is the key.

youtube.com/watch?v=sXNyLYSiPO0

With kind regards,
Oliver K. Manuel
Quantum_Conundrum
1 / 5 (4) Feb 04, 2011
@ QC

ANTI-NEUTRONS.... Now where doesn't that add up?


Google it, moron. You know nothing.

A = GM/r^2

The acceleration gravity on the "surface" of the "core" of a 1M star is around 6.67km/s.

In a 10M Star, the acceleration due to gravity on the surface of the core as it collapses to a neutron star is in the trillions m/s^2.

Absolutely nothing other than anti-matter annihilation can even remotely break even with this, nevermind overcome it.

You can compute the amount of "work" required to explode the shell of matter away from the neutron star at Ve, by integrating the above from A to B where A is radius of the neutron star, and B is radius of the shell at any given time. This is the average of the graviataional acceleration along a curve at escape velocity. If you then multiply this number by the mass displaced and the distance displaced, you get "work".

By E = MC^2 you find it takes about 1/3rd of the initial mass of the star being annihilated to do this.
Quantum_Conundrum
1 / 5 (3) Feb 04, 2011
Since I know you're too lazy.

Anti-neutron:

wikipedia.org/wiki/Antineutron

You can also check the main Physforums site where I proved this is what happened to the "missing mass" in the Crab Nebula using this logic. I calculated to within less than 25% margin of error that the mass energy of this "missing mass" is EXACTLY the amount of energy needed to cause the observed explosion, and this conversion of mass to kinetic energy could only have been accomplished through anti-matter annihilation.

Additionally, in the calculation, I even neglected the fact that the cloud continues to expand with speed greater than escape velocity, so by the time you factor that "excess" energy above the curve, I'm positive all of the missing mass will be there in the form of the kinetic energy.
Quantum_Conundrum
1 / 5 (4) Feb 04, 2011
The acceleration due to gravity on the surface of the Crab Pulsar is between:

947,664,071,429m/s^2 and 1.35 TRILLION m/s^2.

This means that just to break even to explode away, you'd need a FORCE of around 1 trillion Newtons per kilogram mass in the shell that exploded away. In order to obtain escape velocity you need to EXCEED this force for an amount of time sufficient to obtain escape velocity.

By the way, escape velocity of the crab pulsar is 0.648c...

This exceeds the maximum theoretical velocity of an ideal fusion rocket in assymptotically flat space- time.

Translation:

Not a chance in HELL of a fusion explosion or anything else other than anti-matter annihilation overcoming the gravitational acceleration by enough to achieve escape velocity...it simply isn't possible...

Since we can clearly see the nebula exists and expands greater than Ve, then "something" overcame this.

Only the complete conversion of the "missing mass" to kinetic energy can do this.
Thrasymachus
4 / 5 (4) Feb 04, 2011
QC, you're fudging your math too much there. You're assuming the smallest possible radius for any neutron star and the largest possible mass. Neutronium is compressible, which means its density is not a constant, and you can't calculate the gravitational binding energy from it alone. In fact, it only requires about 18% of our sun's mass being converted to energy. Given that we're starting with stars several times more massive than our sun, converting that much mass into energy through fusion alone is more than feasible.
Skeptic_Heretic
5 / 5 (2) Feb 04, 2011
QC, I have two problems here.

First, the gravitational acceleration is ever increasing in intensity. Your energy figures of off by an exponential degree because of this.

Second, once neutronium forms the energy in the reaction increases as the matter is squashed so fast that a lot of the various nuclear binding energies are released creating exactly what you're demanding above, fusion explosions.
Quantum_Conundrum
1 / 5 (3) Feb 04, 2011
QC, I have two problems here.

First, the gravitational acceleration is ever increasing in intensity. Your energy figures of off by an exponential degree because of this.


For the purpose of that calculation, it evens out, because outer shells of the expanding nebula are influenced by the gravity of the inner shells.

Second, once neutronium...


fusion explosions are not enough. You missed the point.

Fusion explosions only convert at most a few percent of the rest mass to energy. For example, the first phase of the proton-proton chain only converts 0.7% of rest mass to other forms of energy.

So if the entire 11M mass had fused instanly from hydrogen to helium, it would only be 1.378E46 joules.

This would be enough energy in flat space time to move the ~5M cloud to it's current velocity, but not in the presence of gravity.
Skeptic_Heretic
not rated yet Feb 05, 2011
fusion explosions are not enough. You missed the point.

Fusion explosions only convert at most a few percent of the rest mass to energy. For example, the first phase of the proton-proton chain only converts 0.7% of rest mass to other forms of energy.

So if the entire 11M mass had fused instanly from hydrogen to helium, it would only be 1.378E46 joules.
No, I think you're missing the point. We're not fusing from H2 to He. We're fusing from H2 to Neutronium. The majority of the rest mass is preserved but you're releasing (potentially) ALL the nuclear binding energy.
Quantum_Conundrum
1 / 5 (1) Feb 05, 2011
Only about 2M got made into neutronium.

The 5M cloud is still ordinary matter: Hydrogen,helium, oxygen, calcium, carbon, lithiusm, etc, with traces of heavy metals.
Resonance
3 / 5 (2) Feb 05, 2011
QC and omatumr are really the same person...