APOD: Supernova Cannon Expels Pulsar J0002 (2022 Oct 02)

[APOD Robot]

Supernova Cannon Expels Pulsar J0002

Explanation: What could shoot out a neutron star like a cannon ball? A supernova. About 10,000 years ago, the supernova that created the nebular remnant CTB 1 not only destroyed a massive star but blasted its newly formed neutron star core -- a pulsar -- out into the Milky Way Galaxy. The pulsar, spinning 8.7 times a second, was discovered using downloadable software Einstein@Home searching through data taken by NASA's orbiting Fermi Gamma-Ray Observatory. Traveling over 1,000 kilometers per second, the pulsar PSR J0002+6216 (J0002 for short) has already left the supernova remnant CTB 1, and is even fast enough to leave our Galaxy. Pictured, the trail of the pulsar is visible extending to the lower left of the supernova remnant. The featured image is a combination of radio images from the VLA and DRAO radio observatories, as well as data archived from NASA's orbiting IRAS infrared observatory. It is well known that supernovas can act as cannons, and even that pulsars can act as cannonballs -- what is not known is how supernovas do it.

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[Ann]

What an amazing image!

I hope I'm allowed to say it, but I am somehow reminded of a sperm fertilizing an egg. Of course, it is the other way round here - the "egg" is empty, except for huge amounts of radiation (which doesn't make it empty, certainly not from a general relativity or quantum mechanics point of view, as Sabine Hossenfelder would say) and the "sperm" is "cannonballing" its way out of it.

Remarkable. As sister Monica Joan of Call the Midwife said, when handyman Fred Buckle had fixed an old telescope for her and she could see the Double Cluster of Perseus.

Remarkable indeed! Both the Double Cluster of Perseus and the supernova pulsar cannonball leaving its egg-shaped shell!

Ann

[ErikTheWise]

No problem. All that is needed is to violate Conservation of Momentum. And yes, that's sarcasm.

[Chris Peterson]

No problem. All that is needed is to violate Conservation of Momentum. And yes, that's sarcasm.

Well, yes, that would work. But it's not hard to see momentum conserved in situations like this. The mass of the remnant is much greater, so its motion is much slower (and harder to detect). I think that lack of understanding here is in why some supernovas are so highly asymmetric in the way the explode. That an asymmetric explosion can lead to this outcome is not hard to understand.

[orin stepanek]

What an amazing image!

I hope I'm allowed to say it, but I am somehow reminded of a sperm fertilizing an egg. Of course, it is the other way round here - the "egg" is empty, except for huge amounts of radiation (which doesn't make it empty, certainly not from a general relativity or quantum mechanics point of view, as Sabine Hossenfelder would say) and the "sperm" is "cannonballing" its way out of it.

Remarkable. As sister Monica Joan of Call the Midwife said, when handyman Fred Buckle had fixed an old telescope for her and she could see the Double Cluster of Perseus.

Remarkable indeed! Both the Double Cluster of Perseus and the supernova pulsar cannonball leaving its egg-shaped shell!

Ann

Maybe that's not an egg Ann! Maybe it's headed there!

Reminds me of Star wars planet destroyer!

Kitty over looking new spaces!

[VictorBorun]

No problem. All that is needed is to violate Conservation of Momentum. And yes, that's sarcasm.

Well, yes, that would work. But it's not hard to see momentum conserved in situations like this. The mass of the remnant is much greater, so its motion is much slower (and harder to detect). I think that lack of understanding here is in why some supernovas are so highly asymmetric in the way the explode. That an asymmetric explosion can lead to this outcome is not hard to understand.

there are 2 poles of the maximum brightness of the shell of the SNR, one directly under the 1000 km/s cannonball pulsar neutron star.
So there is a symmetry to the SN explosion.
There may be even a second cannonball, twice the mass and 500 km/s the speed, aproaching the other pole of the shell from inside and going to become visible soon. If so, the third mass may well stay in the center of the shell.
By the way, do we know any candidate remnant dwarf stars near the center of the shell?

Now if you want to wonder at a complex conservation of an impact momentum, look at Dimorphous' ejecta in radiowaves:

The impact momentum's direction is 5 o'clock, the bisector of the two longest jets

Could the SN in this APOD be caused by an impact with a cannonball, I wonder

[Chris Peterson]

No problem. All that is needed is to violate Conservation of Momentum. And yes, that's sarcasm.

Well, yes, that would work. But it's not hard to see momentum conserved in situations like this. The mass of the remnant is much greater, so its motion is much slower (and harder to detect). I think that lack of understanding here is in why some supernovas are so highly asymmetric in the way the explode. That an asymmetric explosion can lead to this outcome is not hard to understand.

there are 2 poles of the maximum brightness of the shell of the SNR, one directly under the 1000 km/s cannonball pulsar neutron star.
So there is a symmetry to the SN explosion.
There may be even a second cannonball, twice the mass and 500 km/s the speed, aproaching the other pole of the shell from inside and going to become visible soon. If so, the third mass may well stay in the center of the shell.
By the way, do we know any candidate remnant dwarf stars near the center of the shell?

Now if you want to wonder at a complex conservation of an impact momentum, look at Dimorphous' ejecta in radiowaves:

The impact momentum's direction is 5 o'clock, the bisector of the two longest jets

There are two issues- non-spherical symmetry and any completely non-symmetric expansion. I think both are observed to exist. Which this is isn't entirely clear (you may well be right that there is a polar symmetry here, as we see with many supernovas). There are several examples of ejected progenitors; I don't know of any examples of polar pairs of them, however.

[heehaw]

There are background stars, of course. There seems to be one just ahead of the jet (the neutron star). Or is it a star? could it be somehow part of the ejection? Oh, and it just occurs to me to ask, is the speed of ejection (and distance of the system from us) such that photos years from now might resolve that by detecting the motion? The whole picture is utterly fascinating. At Space Telescope there'll be a talk soon ... by the discoverer of pulsars! Seems like a million years ago that happened.

[Astronymus]

That's one heck of a mass accelerator...

[johnnydeep]

Well, yes, that would work. But it's not hard to see momentum conserved in situations like this. The mass of the remnant is much greater, so its motion is much slower (and harder to detect). I think that lack of understanding here is in why some supernovas are so highly asymmetric in the way the explode. That an asymmetric explosion can lead to this outcome is not hard to understand.

there are 2 poles of the maximum brightness of the shell of the SNR, one directly under the 1000 km/s cannonball pulsar neutron star.
So there is a symmetry to the SN explosion.
There may be even a second cannonball, twice the mass and 500 km/s the speed, aproaching the other pole of the shell from inside and going to become visible soon. If so, the third mass may well stay in the center of the shell.
By the way, do we know any candidate remnant dwarf stars near the center of the shell?

Now if you want to wonder at a complex conservation of an impact momentum, look at Dimorphous' ejecta in radiowaves:

The impact momentum's direction is 5 o'clock, the bisector of the two longest jets

There are two issues- non-spherical symmetry and any completely non-symmetric expansion. I think both are observed to exist. Which this is isn't entirely clear (you may well be right that there is a polar symmetry here, as we see with many supernovas). There are several examples of ejected progenitors; I don't know of any examples of polar pairs of them, however.

The other problem is that a supernova only produces one neutron star or pulsar. At least, I can't image (or explain how!) two being created!

[Chris Peterson]

there are 2 poles of the maximum brightness of the shell of the SNR, one directly under the 1000 km/s cannonball pulsar neutron star.
So there is a symmetry to the SN explosion.
There may be even a second cannonball, twice the mass and 500 km/s the speed, aproaching the other pole of the shell from inside and going to become visible soon. If so, the third mass may well stay in the center of the shell.
By the way, do we know any candidate remnant dwarf stars near the center of the shell?

Now if you want to wonder at a complex conservation of an impact momentum, look at Dimorphous' ejecta in radiowaves:

The impact momentum's direction is 5 o'clock, the bisector of the two longest jets

There are two issues- non-spherical symmetry and any completely non-symmetric expansion. I think both are observed to exist. Which this is isn't entirely clear (you may well be right that there is a polar symmetry here, as we see with many supernovas). There are several examples of ejected progenitors; I don't know of any examples of polar pairs of them, however.

The other problem is that a supernova only produces one neutron star or pulsar. At least, I can't image (or explain how!) two being created!

Agreed... although many if not most such systems are binary, so a companion could conceivably be ejected in some direction. And there could be cases where that companion was a neutron star.

[johnnydeep]

There are two issues- non-spherical symmetry and any completely non-symmetric expansion. I think both are observed to exist. Which this is isn't entirely clear (you may well be right that there is a polar symmetry here, as we see with many supernovas). There are several examples of ejected progenitors; I don't know of any examples of polar pairs of them, however.

The other problem is that a supernova only produces one neutron star or pulsar. At least, I can't image (or explain how!) two being created!

Agreed... although many if not most such systems are binary, so a companion could conceivably be ejected in some direction. And there could be cases where that companion was a neutron star.

Ah, yes - I forgot about the possibility of a companion. Perhaps the SN ejected the pulsar into it and sent it caroming off - cosmic billiards writ large! Though I suppose if they actually collided, they would almost certainly merge.

[VictorBorun]

if they actually collided, they would almost certainly merge

not if the impactor went at 1000 km/s, much faster than the escape velocity of a star.

A neutron star has an escape velocity about c/2 = 150,000 km/s and can merge with another neutron star (creating a kilonova).
A white dwarf has an escape velocity about 5000 km/s and can merge with a 1000 km/s cannon ball neutron star.

But our Sun has an escape velocity of just 615 km/s and so would not merge with a 1000 km/s cannon ball neutron star. If hit by such, much of our Sun will get thrown about

[VictorBorun]

many if not most such systems are binary, so a companion could conceivably be ejected in some direction. And there could be cases where that companion was a neutron star.

does a binary make for a kicked out cannonball star?

I can see how a triple system does it. Let there be, say,
a 1 sun mass star/dwarf/neutron star,
a 10 suns mass star/black hole, and
a 30 suns mass star/black hole.

Now the interaction is likely to let the 10-sunner sink to a low orbit and the 1-sunner soar to a higher orbit while preserving the total spin.
For the 10-sunner to stop the 1-sunner must accelerate to 10 times faster speed; it can well become a cannonball object, can it not?

[heehaw]

I still would like to know if photos years from now will show changes. I hope so, of course.

[Chris Peterson]

I still would like to know if photos years from now will show changes. I hope so, of course.

Well, you can do a back of the envelope calculation. If we take the distance as around 3 kpc, and assume the motion is radial at 1000 km/s, that translates to about a milliarcsecond per year change in position. That's about what we could measure instrumentally, but not enough over decades or even centuries to look significantly different in an image at a scale like this. (The actual motion is probably less, since the direction is probably not purely radial to our line of sight.)

[jamjam]

Well the mechanism wasn't known back in 2019 when this first appeared, but recently it’s been proposed https://phys.org/news/2022-08-neutrino ... lsars.html that neutrino emission which is asymmetrical because such emission can violate parity causes the pulsars to jet off, and I’d bet that's right.

[Rauf]

So what is supernova plural form?? Is it supernovas or supernovae??

[Ann]

So what is supernova plural form?? Is it supernovas or supernovae??

Chris will tell you it is supernovas. He has convinced me, too.

Ann

[Chris Peterson]

So what is supernova plural form?? Is it supernovas or supernovae??

Chris will tell you it is supernovas. He has convinced me, too. :wink:

I would say that in English, being a descriptive, not prescriptive language, the plural form is determined by usage. And both forms here are common and widely used. Where there is a form that follows normal English convention alongside a historical Latin form, I generally prefer the former.

[johnnydeep]

Well the mechanism wasn't known back in 2019 when this first appeared, but recently it’s been proposed https://phys.org/news/2022-08-neutrino ... lsars.html that neutrino emission which is asymmetrical because such emission can violate parity causes the pulsars to jet off, and I’d bet that's right.

Wow! That's pretty cool. From the link:

It has been shown that Cooper pairs of neutrons that have been formed by neutron binding also undergo gyrator motion in the superfluid region of neutron stars. Based on calculations, the researchers discovered that these left- and right-handed neutrinos, which are emitted by neutron Cooper pairs, have high energies.

Furthermore, left-handed neutrinos and right-handed neutrinos emit in the same direction due to their non-conservation of parity. As a result of the conservation of momentum, when a neutron star emits a neutrino stream along its rotation axis, the neutron star itself acquires a recoil velocity in the forward direction along its rotation axis.

So, I wonder how long this "neutrino beam rocket" can fire, and if there is any upper limit (other than c of course) to how fast it can propel the neutron star.

[johnnydeep]

if they actually collided, they would almost certainly merge

not if the impactor went at 1000 km/s, much faster than the escape velocity of a star.

A neutron star has an escape velocity about c/2 = 150,000 km/s and can merge with another neutron star (creating a kilonova).
A white dwarf has an escape velocity about 5000 km/s and can merge with a 1000 km/s cannon ball neutron star.

But our Sun has an escape velocity of just 615 km/s and so would not merge with a 1000 km/s cannon ball neutron star. If hit by such, much of our Sun will get thrown about

Yes, a neutron star colliding with the Sun at 1000 km/s would certainly wreck havoc. But I would think that a direct hit would still cause a merger. 1000 km/s is not even double the 615 km/s escape velocity of the Sun. I suspect the neutron star would oscillate around the core of the Sun until it finally sank to the center.

[Chris Peterson]

if they actually collided, they would almost certainly merge

not if the impactor went at 1000 km/s, much faster than the escape velocity of a star.

A neutron star has an escape velocity about c/2 = 150,000 km/s and can merge with another neutron star (creating a kilonova).
A white dwarf has an escape velocity about 5000 km/s and can merge with a 1000 km/s cannon ball neutron star.

But our Sun has an escape velocity of just 615 km/s and so would not merge with a 1000 km/s cannon ball neutron star. If hit by such, much of our Sun will get thrown about

Yes, a neutron star colliding with the Sun at 1000 km/s would certainly wreck havoc. But I would think that a direct hit would still cause a merger. 1000 km/s is not even double the 615 km/s escape velocity of the Sun. I suspect the neutron star would oscillate around the core of the Sun until it finally sank to the center.

A neutron star colliding with the Sun at 1000 km/s would continue on its way with an altered path. It would shred the Sun and probably capture some of its material, but the two bodies (or remnants) would not be in closed orbits around each other, and most of the Sun's material would be left behind.

[johnnydeep]

not if the impactor went at 1000 km/s, much faster than the escape velocity of a star.

A neutron star has an escape velocity about c/2 = 150,000 km/s and can merge with another neutron star (creating a kilonova).
A white dwarf has an escape velocity about 5000 km/s and can merge with a 1000 km/s cannon ball neutron star.

But our Sun has an escape velocity of just 615 km/s and so would not merge with a 1000 km/s cannon ball neutron star. If hit by such, much of our Sun will get thrown about

Yes, a neutron star colliding with the Sun at 1000 km/s would certainly wreck havoc. But I would think that a direct hit would still cause a merger. 1000 km/s is not even double the 615 km/s escape velocity of the Sun. I suspect the neutron star would oscillate around the core of the Sun until it finally sank to the center.

A neutron star colliding with the Sun at 1000 km/s would continue on its way with an altered path. It would shred the Sun and probably capture some of its material, but the two bodies (or remnants) would not be in closed orbits around each other, and most of the Sun's material would be left behind.

That's hard to believe, but I'll take your word for it. I guess given the vast density, size, (and mass difference of up to 2x), it would be like a bullet passing through two bullet's of mass spread evenly through a 70000 cm (700 km) radius sphere. Any idea how much the neutron star's speed would be reduced? The Sun is about 700,000 km in radius, so the neutron star would spend 1400 seconds (23 minutes) passing though and within the Sun's gravity well.

[Rauf]

So what is supernova plural form?? Is it supernovas or supernovae??

Chris will tell you it is supernovas. He has convinced me, too.

I would say that in English, being a descriptive, not prescriptive language, the plural form is determined by usage. And both forms here are common and widely used. Where there is a form that follows normal English convention alongside a historical Latin form, I generally prefer the former.

Oh I see, I guess the same goes for nebulas and nebulae then! I prefer the former as well in both.