Astronomers observe subpulse drifting and nulling of pulsar PSR J0026–1955

https://phys.org/news/2023-07-astronomers-subpulse-drifting-nulling-pulsar.html

by wglb • 3 years ago

20 14 3 years ago

phys.org

coolspot• 3 years ago

Likely LED lamps inside the pulsar are near their service age.

Just replace the whole thing.

dmvdoug5• 3 years ago

Discovered in 2018, PSR J0026–1955 is a Galactic pulsar with a spin period of approximately 1.306 seconds and dispersion measure of 20.81 pc/cm3. It has a spin-down luminosity of 23 nonillion erg/s, surface magnetic field strength of 770 billion Gauss, and its characteristic age is estimated to be some 47 million years.

Fascinating.

I have no idea what any of those words mean.

imchillyb• 3 years ago

My take as a layman: The pulsar blinks. The blinks are tied to spin, the form of the electromagnetic beam, and its electromagnetic cloud. The measurements are of the beam, its time, its output in luminosity and the uh.. force of the electromagnetic beam? Also, it's not that old.

dmbche• 3 years ago

I'll keeo looking, but for starters, Earths magnetic field is between 0.25-0.65 gauss - for scale. I think the spin period means it revolves fully in 1.03 second while earth takes 24h.

Edit: I'm sorry - 1.03 second between every pulse, and the pulsar has two jets coming out at the poles, so double that for a rotation.

For fhe spin down luminosity - from my understanding, we measure the amount of energy it exerts per rotation by how slower it turns by every rotation, which is represented as luminosity for a mysterious reason to me but I imagine it's because it's very small? An erg being 100 nJ.

For the last figure, it represent the electrons between us and the pulsar per area (if you think about it as a laser, the amount of electrons pushed by the laser)

Here is an example

"Example

The binary pulsar PSR J0437-4715 has had its parallax distance determined from pulsar timing to be 156 pc. The dispersion of 2.643 pc cm-3 means that the mean electron density between the Earth and the pulsar is:

ne = DM/D = 2.643/156 = 0.017 electrons/cm3"

From https://astronomy.swin.edu.au/cosmos/p/pulsar+dispersion+mea...

dmvdoug5• 3 years ago

I thought spin down had something to do with pseudo-angular momentum of, like, electrons, but after Googling I see it definitely means spin down as the opposite of, like, spinning up an engine or a Docker container. Which is exactly what you said. Which is exactly why I didn’t try to guess what these things meant, because I had no idea. :)

dandelany• 3 years ago

If I may take a layman stab:

Spin period: how long does it take the pulsar to fully rotate once, ie. how often does it “flash”?

Dispersion measure: from our perspective, how much is the flash “smeared” across time and frequency vs. just being a narrow-band sharp pulse? This is a function of how much stuff (electrons) exists between us and the pulsar.

Spin-down luminosity: how much of the pulsar’s kinetic energy is being lost as electromagnetic radiation? Pulsars spin more slowly over time due to this, so how hard are the brakes being pressed?

Surface magnetic field strength: what it says on the tin, how strong is the magnetic field on the surface of the pulsar? Refrigerator magnets are 10-100 gauss, a powerful MRI might be 30,000 gauss.

Characteristic age: estimated age of the pulsar calculated by assuming a very fast initial spin & applying the known spin-down rate to see how long it would take to slow down to its current rate. Makes some “spherical cow” assumptions but should be a good rough estimate of its age.

spiffistan• 3 years ago

That's one of the most jargon-dense sentences I've ever read

DontchaKnowit• 3 years ago

Try reading a modern AI/machuine learning paper

dmvdoug5• 3 years ago

I know! The first time I read it I was like oh OK and then I reread it and I was like yup I don’t understand any of it.

Arrath• 3 years ago

Unsurprisingly, that magnetic field is well beyond the strength required to tear apart our squishy bodies.

"Fields in excess of 10^9 Gauss, however, would be instantly lethal. Such fields strongly distort atoms, compressing atomic electron clouds into cigar shapes, with the long axis aligned with the field, thus rendering the chemistry of life impossible. A magnetar within 1000 kilometers would thus kill you via pure static magnetism -- if it didn't already get you with X-rays, gamma rays, high energy particles, extreme gravity, bursts and flares..."

https://physics.stackexchange.com/questions/119999/is-it-pos...

Astronomers observe subpulse drifting and nulling of pulsar PSR J0026–1955

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