Smallest speed jump of pulsar caused by billions of superfluid vortices

Apr 17, 2014
Artist’s impression of a pulsar. Pulsars are rotating neutron stars -- remnants of massive stars that end their lives in supernova explosions. They act like cosmic lighthouses whose beams sweep through the universe. Credit: NASA

A team of astronomers, including Danai Antonopoulou and Anna Watts from the University of Amsterdam, has discovered that sudden speed jumps in the rotational velocity of pulsars have a minimum size, and that they are caused not by the unpinning and displacement of just one sub-surface superfluid vortex, but by billions. This result is important to our understanding of the behavior of matter under extreme conditions, and has been published this week in the journal Monthly Notices of the Royal Astronomical Society.

Pulsars are rotating neutron stars - remnants of massive stars that end their lives in supernova explosions. They act like cosmic lighthouses whose beams sweep through the Universe. Their rotational velocity decreases in time, but can suddenly increase in rare events called glitches. These glitches are caused by the unpinning and displacement of vortices that connect the crust with the mixture of particles containing superfluid neutrons beneath the crust.

The team of astronomers discovered that the glitches of the Crab Pulsar always involve a decrease in the rotational period of at least 0.055 nanoseconds. The Crab Pulsar was one of the first pulsars to be discovered and has been observed almost daily with the 42-ft Telescope at the Jodrell Bank Observatory over the last 29 years. The huge amount of data makes this object the best choice to study glitches.

The smallest is likely to be caused by the unpinning and movement of billions of vortices. "Surprisingly, no one tried to determine a lower limit to glitch size before. Many assumed that the smallest glitch would be caused by a single vortex unpinning. The smallest glitch is clearly much larger than we expected", says Danai Antonopoulou from the University of Amsterdam (UvA).

"Astronomers would of course like to know whether the smallest glitches of other pulsars are also caused by billions of vortices. The next step is to sift through the data of other pulsars and to continue observing", says first author Cristobal Espinoza (IA-PUC, Chile). Antonopoulou's supervisor Anna Watts (UvA) adds: "By comparing the observations with theoretical predictions we learn about the behavior of matter in these exotic objects. The precise cause of glitches is still a mystery to us, and this result offers a new challenge to theorists."

Explore further: Former missile-tracking telescope helps reveal fate of baby pulsar

More information: "Neutron star glitches have a substantial minimum size," C. M. Espinoza, D. Antonopoulou, B. W. Stappers, A. Watts, A. G. Lyne, Monthly Notices of the Royal Astronomical Society, MNRAS (2014) 440 (3): 2755 dx.doi.org/10.1093/mnras/stu395, preprint: arxiv.org/abs/1402.7219

add to favorites email to friend print save as pdf

Related Stories

A glitch in pulsar J1718-3718

Jun 29, 2011

Pulsars are noted as being some of the universe’s best clocks. Their highly magnetized nature gives rise to beams of high energy radiation that sweep out across the universe. If these beams pass Earth, ...

A pulsar with a tremendous hiccup

Jul 24, 2012

(Phys.org) -- Pulsars are superlative cosmic beacons. These compact neutron stars rotate about their axes many times per second, emitting radio waves and gamma radiation into space.  Using ingenious data ...

Triple millisecond pulsar laboratory challenges theory

Jan 06, 2014

(Phys.org) —Millisecond pulsars are old neutron stars, which rotate several hundred times per second. They are often found in binary systems and their existence can be explained by mass transfer from a ...

Recommended for you

Image: NGC 6872 in the constellation of Pavo

3 hours ago

This picture, taken by the NASA/ESA Hubble Space Telescope's Wide Field Planetary Camera 2 (WFPC2), shows a galaxy known as NGC 6872 in the constellation of Pavo (The Peacock). Its unusual shape is caused ...

Measuring the proper motion of a galaxy

4 hours ago

The motion of a star relative to us can be determined by measuring two quantities, radial motion and proper motion. Radial motion is the motion of a star along our line of sight. That is, motion directly ...

Gravitational waves according to Planck

21 hours ago

Scientists of the Planck collaboration, and in particular the Trieste team, have conducted a series of in-depth checks on the discovery recently publicized by the Antarctic Observatory, which announced last ...

Infant solar system shows signs of windy weather

21 hours ago

Astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) have observed what may be the first-ever signs of windy weather around a T Tauri star, an infant analog of our own Sun. This may help ...

Finding hints of gravitational waves in the stars

Sep 22, 2014

Scientists have shown how gravitational waves—invisible ripples in the fabric of space and time that propagate through the universe—might be "seen" by looking at the stars. The new model proposes that ...

How gamma ray telescopes work

Sep 22, 2014

Yesterday I talked about the detection of gamma ray bursts, intense blasts of gamma rays that occasionally appear in distant galaxies. Gamma ray bursts were only detected when gamma ray satellites were put ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

cantdrive85
1.8 / 5 (5) Apr 17, 2014
The only glitch here is the theory...